A network of cross-linked hydrophilic macromolecules used in biomedical applications.
Water swollen, rigid, 3-dimensional network of cross-linked, hydrophilic macromolecules, 20-95% water. They are used in paints, printing inks, foodstuffs, pharmaceuticals, and cosmetics. (Grant & Hackh's Chemical Dictionary, 5th ed)
Synthetic or natural materials, other than DRUGS, that are used to replace or repair any body TISSUES or bodily function.
Soft, supple contact lenses made of plastic polymers which interact readily with water molecules. Many types are available, including continuous and extended-wear versions, which are gas-permeable and easily sterilized.
Polymers of ETHYLENE OXIDE and water, and their ethers. They vary in consistency from liquid to solid depending on the molecular weight indicated by a number following the name. They are used as SURFACTANTS, dispersing agents, solvents, ointment and suppository bases, vehicles, and tablet excipients. Some specific groups are NONOXYNOLS, OCTOXYNOLS, and POLOXAMERS.
Generating tissue in vitro for clinical applications, such as replacing wounded tissues or impaired organs. The use of TISSUE SCAFFOLDING enables the generation of complex multi-layered tissues and tissue structures.
Cell growth support structures composed of BIOCOMPATIBLE MATERIALS. They are specially designed solid support matrices for cell attachment in TISSUE ENGINEERING and GUIDED TISSUE REGENERATION uses.
A polymer prepared from polyvinyl acetates by replacement of the acetate groups with hydroxyl groups. It is used as a pharmaceutic aid and ophthalmic lubricant as well as in the manufacture of surface coatings artificial sponges, cosmetics, and other products.
Term used to designate tetrahydroxy aldehydic acids obtained by oxidation of hexose sugars, i.e. glucuronic acid, galacturonic acid, etc. Historically, the name hexuronic acid was originally given to ascorbic acid.
The testing of materials and devices, especially those used for PROSTHESES AND IMPLANTS; SUTURES; TISSUE ADHESIVES; etc., for hardness, strength, durability, safety, efficacy, and biocompatibility.
A sugar acid formed by the oxidation of the C-6 carbon of GLUCOSE. In addition to being a key intermediate metabolite of the uronic acid pathway, glucuronic acid also plays a role in the detoxification of certain drugs and toxins by conjugating with them to form GLUCURONIDES.
A product formed from skin, white connective tissue, or bone COLLAGEN. It is used as a protein food adjuvant, plasma substitute, hemostatic, suspending agent in pharmaceutical preparations, and in the manufacturing of capsules and suppositories.
Salts of alginic acid that are extracted from marine kelp and used to make dental impressions and as absorbent material for surgical dressings.
A broad family of synthetic organosiloxane polymers containing a repeating silicon-oxygen backbone with organic side groups attached via carbon-silicon bonds. Depending on their structure, they are classified as liquids, gels, and elastomers. (From Merck Index, 12th ed)
Hydrophilic contact lenses worn for an extended period or permanently.
Acrylic resins, also known as polymethyl methacrylate (PMMA), are a type of synthetic resin formed from polymerized methyl methacrylate monomers, used in various medical applications such as dental restorations, orthopedic implants, and ophthalmic lenses due to their biocompatibility, durability, and transparency.
A biocompatible, hydrophilic, inert gel that is permeable to tissue fluids. It is used as an embedding medium for microscopy, as a coating for implants and prostheses, for contact lenses, as microspheres in adsorption research, etc.
A nonionic polyoxyethylene-polyoxypropylene block co-polymer with the general formula HO(C2H4O)a(-C3H6O)b(C2H4O)aH. It is available in different grades which vary from liquids to solids. It is used as an emulsifying agent, solubilizing agent, surfactant, and wetting agent for antibiotics. Poloxamer is also used in ointment and suppository bases and as a tablet binder or coater. (Martindale The Extra Pharmacopoeia, 31st ed)
Colorless, odorless crystals that are used extensively in research laboratories for the preparation of polyacrylamide gels for electrophoresis and in organic synthesis, and polymerization. Some of its polymers are used in sewage and wastewater treatment, permanent press fabrics, and as soil conditioning agents.
Microbial, plant, or animal cells which are immobilized by attachment to solid structures, usually a column matrix. A common use of immobilized cells is in biotechnology for the bioconversion of a substrate to a particular product. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
Polymers of organic acids and alcohols, with ester linkages--usually polyethylene terephthalate; can be cured into hard plastic, films or tapes, or fibers which can be woven into fabrics, meshes or velours.
The study of the deformation and flow of matter, usually liquids or fluids, and of the plastic flow of solids. The concept covers consistency, dilatancy, liquefaction, resistance to flow, shearing, thixotrophy, and VISCOSITY.
Lenses designed to be worn on the front surface of the eyeball. (UMDNS, 1999)
Condition of having pores or open spaces. This often refers to bones, bone implants, or bone cements, but can refer to the porous state of any solid substance.
Small uniformly-sized spherical particles, of micrometer dimensions, frequently labeled with radioisotopes or various reagents acting as tags or markers.
Acrylates are a group of synthetic compounds based on acrylic acid, commonly used in various industrial and medical applications such as adhesives, coatings, and dental materials, known to cause allergic reactions and contact dermatitis in sensitive individuals.
Deacetylated CHITIN, a linear polysaccharide of deacetylated beta-1,4-D-glucosamine. It is used in HYDROGEL and to treat WOUNDS.
Dosage forms of a drug that act over a period of time by controlled-release processes or technology.
Numerical expression indicating the measure of stiffness in a material. It is defined by the ratio of stress in a unit area of substance to the resulting deformation (strain). This allows the behavior of a material under load (such as bone) to be calculated.
Acrylic acids or acrylates which are substituted in the C-2 position with a methyl group.
The properties and processes of materials that affect their behavior under force.
Dressings comprised of a self-adhesive matrix to which hydrophilic absorbent particles are embedded. The particles consist of CELLULOSE derivatives; calcium ALGINATES; PECTINS; or GELS. The utility is based on providing a moist environment for WOUND HEALING.
A natural high-viscosity mucopolysaccharide with alternating beta (1-3) glucuronide and beta (1-4) glucosaminidic bonds. It is found in the UMBILICAL CORD, in VITREOUS BODY and in SYNOVIAL FLUID. A high urinary level is found in PROGERIA.
Methods for maintaining or growing CELLS in vitro.
Submicron-sized fibers with diameters typically between 50 and 500 nanometers. The very small dimension of these fibers can generate a high surface area to volume ratio, which makes them potential candidates for various biomedical and other applications.
Systems for the delivery of drugs to target sites of pharmacological actions. Technologies employed include those concerning drug preparation, route of administration, site targeting, metabolism, and toxicity.
Materials fabricated by BIOMIMETICS techniques, i.e., based on natural processes found in biological systems.
Sterile solutions used to clean and disinfect contact lenses.
Introduction of substances into the body using a needle and syringe.
Forms to which substances are incorporated to improve the delivery and the effectiveness of drugs. Drug carriers are used in drug-delivery systems such as the controlled-release technology to prolong in vivo drug actions, decrease drug metabolism, and reduce drug toxicity. Carriers are also used in designs to increase the effectiveness of drug delivery to the target sites of pharmacological actions. Liposomes, albumin microspheres, soluble synthetic polymers, DNA complexes, protein-drug conjugates, and carrier erythrocytes among others have been employed as biodegradable drug carriers.
Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY.
Compounds formed by the joining of smaller, usually repeating, units linked by covalent bonds. These compounds often form large macromolecules (e.g., BIOPOLYMERS; PLASTICS).
Polymers of silicone that are formed by crosslinking and treatment with amorphous silica to increase strength. They have properties similar to vulcanized natural rubber, in that they stretch under tension, retract rapidly, and fully recover to their original dimensions upon release. They are used in the encapsulation of surgical membranes and implants.
Implants constructed of materials designed to be absorbed by the body without producing an immune response. They are usually composed of plastics and are frequently used in orthopedics and orthodontics.
Bone-marrow-derived, non-hematopoietic cells that support HEMATOPOETIC STEM CELLS. They have also been isolated from other organs and tissues such as UMBILICAL CORD BLOOD, umbilical vein subendothelium, and WHARTON JELLY. These cells are considered to be a source of multipotent stem cells because they include subpopulations of mesenchymal stem cells.
Reagents with two reactive groups, usually at opposite ends of the molecule, that are capable of reacting with and thereby forming bridges between side chains of amino acids in proteins; the locations of naturally reactive areas within proteins can thereby be identified; may also be used for other macromolecules, like glycoproteins, nucleic acids, or other.
The resistance that a gaseous or liquid system offers to flow when it is subjected to shear stress. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
The sodium salt of BENZOIC ACID. It is used as an antifungal preservative in pharmaceutical preparations and foods. It may also be used as a test for liver function.
Substances used to cause adherence of tissue to tissue or tissue to non-tissue surfaces, as for prostheses.
Process by which unwanted microbial, plant or animal materials or organisms accumulate on man-made surfaces.
An interdisciplinary field in materials science, ENGINEERING, and BIOLOGY, studying the use of biological principles for synthesis or fabrication of BIOMIMETIC MATERIALS.
Relating to the size of solids.
Artificial substitutes for body parts and materials inserted into organisms during experimental studies.
Material used for wrapping or binding any part of the body.
The span of viability of a cell characterized by the capacity to perform certain functions such as metabolism, growth, reproduction, some form of responsiveness, and adaptability.
Characteristics or attributes of the outer boundaries of objects, including molecules.
Biological activities and functions of the SKIN.
A group of glucose polymers made by certain bacteria. Dextrans are used therapeutically as plasma volume expanders and anticoagulants. They are also commonly used in biological experimentation and in industry for a wide variety of purposes.
Poly-2-methylpropenoic acids. Used in the manufacture of methacrylate resins and plastics in the form of pellets and granules, as absorbent for biological materials and as filters; also as biological membranes and as hydrogens. Synonyms: methylacrylate polymer; poly(methylacrylate); acrylic acid methyl ester polymer.
A technique for maintaining or growing TISSUE in vitro, usually by DIFFUSION, perifusion, or PERFUSION. The tissue is cultured directly after removal from the host without being dispersed for cell culture.

Lysozyme sorption in hydrogel contact lenses. (1/453)

PURPOSE: To examine the processes involved in formation of protein deposits on hydrogel contact lenses. METHODS: The adsorption and/or penetration of lysozyme on or into three types of contact lenses, etafilcon A, vifilcon A, and tefilcon, were investigated in vitro using a radiolabel-tracer technique, x-ray photoelectron spectroscopy, and laser scanning confocal microscopy. RESULTS: Binding of lysozyme to high-water-content, ionic contact lenses (etafilcon A and vifilcon A) was dominated by a penetration process. The extent of this penetration was a function of charge density of the lenses, so that there was a higher degree of penetration of lysozyme in etafilcon A than in vifilcon A lenses. In contrast, the binding of lysozyme to tefilcon lenses was a surface adsorption process. The adsorption and desorption kinetics showed similar trends to those found in human serum albumin (HSA) adsorption on lens surfaces. However, the extent of lysozyme adsorption on tefilcon is much higher than HSA adsorption, probably because of the self-association of lysozyme on the tefilcon lens surface. Furthermore, either penetration or adsorption of lysozyme involved reversible and irreversible processes and were both time dependent. CONCLUSIONS: Binding of lysozyme to hydrogel lenses involves surface adsorption or matrix penetration. These processes may be reversible or irreversible. The properties of the lens materials, such as charge density (ionicity) and porosity (water content) of the lenses, determine the type and rates of these processes.  (+info)

Sympathetic swelling response of the control eye to soft lenses in the other eye. (2/453)

PURPOSE: To compare central corneal swelling and light scatter after 8 hours of sleep in eyes wearing high- and low-Dk hydrogel lenses and to the contralateral control eyes. METHODS: Twenty neophyte subjects wore a Lotrafilcon A (Dk, 140; Ciba Vision, Duluth GA) silicone hydrogel lens and an Etafilcon A (Dk, 18; Acuvue; Vistakon, Jacksonville, FL) 58% water content hydrogel lens of similar center thickness in random order in the right eye only, for overnight 8-hour periods. The contralateral nonwearing left eyes served as controls. Central corneal thickness was measured using an optical pachometer and light scatter using a Van den Berg stray-light meter before lens insertion, after lens removal on waking, and every 20 minutes for the next 3 hours. RESULTS: Central corneal swelling induced by the Etafilcon A lens on eye opening was significantly higher than with the Lotrafilcon A lens (8.66%+/-2.84% versus 2.71%+/-1.91%; P<0.00001). Light scatter induced by the Etafilcon A lens on eye opening was significantly higher than with the Lotrafilcon A lens (46.09+/-5.62 versus 42.78+/-6.07 Van den Berg units, P = 0.0078). The swelling of the control eyes paired with the Etafilcon A lens-wearing eyes was also slightly but significantly higher than that of the control eyes paired with the Lotrafilcon A lens-wearing eyes (2.34%+/-1.26% versus 1.44%+/-0.91%; P = 0.0002). Light-scatter measurements were not significantly different between control sets of eyes but showed the same trend. CONCLUSIONS: In neophyte subjects, corneal swelling of the contralateral control eyes appears to be influenced by the swelling of the fellow lens-wearing eyes-that is, the swelling of the contralateral control eye was significantly lower when there was less swelling of the fellow eye wearing the high-Dk lens. Although there was no statistically significant difference in light-scatter measurements between the control sets of eyes, a trend similar to the corneal swelling results was observed, which could be used to support the suggestion that this may be a sympathetic physiological response rather than an unusual sampling coincidence.  (+info)

Orally administered, insulin-loaded amidated pectin hydrogel beads sustain plasma concentrations of insulin in streptozotocin-diabetic rats. (3/453)

We report successful oral administration of insulin entrapped in amidated pectin hydrogel beads in streptozotocin (STZ)-diabetic rats, with a concomitant reduction in plasma glucose concentration. The pectin-insulin (PI) beads were prepared by the gelation of humilin-pectin solutions in the presence of calcium. Separate groups of STZ-diabetic rats were orally administered two PI beads (30 micrograms insulin) once or twice daily or three beads (46 micrograms) once daily for 2 weeks. Control non-diabetic and STZ-diabetic rats were orally administered pectin hydrogel drug-free beads. By comparison with control non-diabetic rats, untreated STZ-diabetic rats exhibited significantly low plasma insulin concentration (0.32+/-0. 03 ng/ml, n=6, compared with 2.60+/-0.44 ng/ml in controls, n=6) and increased plasma glucose concentrations (25.84+/-1.44 mmol/l compared with 10.72+/- 0.52 mmol/l in controls). Administration of two PI beads twice daily (60 micrograms active insulin) or three beads (46 micrograms) once a day to STZ-diabetic rats increased plasma insulin concentrations (0.89+/-0.09 ng/ml and 1.85+/- 0.26 ng/ml, respectively), with a concomitant reduction in plasma glucose concentration (15.45+/-1.63 mmol/l and 10.56+/-0.26 mmol/l, respectively). However, a single dose of PI beads (30 micrograms) did not affect plasma insulin concentrations, although plasma glucose concentrations (17.82+/-2.98 mmol/l) were significantly reduced compared with those in untreated STZ-diabetic rats. Pharmacokinetic parameters in STZ-diabetic rats show that the orally administered PI beads (30 micrograms insulin) were more effective in sustaining plasma insulin concentrations than was s.c. insulin (30 micrograms). The data from this study suggest that this insulin-loaded amidated pectin hydrogel bead formulation not only produces sustained release of insulin, but may also reduce plasma glucose concentration in diabetes mellitus.  (+info)

Biomechanical and histological evaluation of hydrogel implants in articular cartilage. (4/453)

We evaluated the mechanical behavior of the repaired surfaces of defective articular cartilage in the intercondylar region of the rat femur after a hydrogel graft implant. The results were compared to those for the adjacent normal articular cartilage and for control surfaces where the defects remained empty. Hydrogel synthesized by blending poly(2-hydroxyethyl methacrylate) and poly(methyl methacrylate-co-acrylic acid) was implanted in male Wistar rats. The animals were divided into five groups with postoperative follow-up periods of 3, 5, 8, 12 and 16 weeks. Indentation tests were performed on the neoformed surfaces in the knee joint (with or without a hydrogel implant) and on adjacent articular cartilage in order to assess the mechanical properties of the newly formed surface. Kruskal-Wallis analysis indicated that the mechanical behavior of the neoformed surfaces was significantly different from that of normal cartilage. Histological analysis of the repaired defects showed that the hydrogel implant filled the defect with no signs of inflammation as it was well anchored to the surrounding tissues, resulting in a newly formed articular surface. In the case of empty control defects, osseous tissue grew inside the defects and fibrous tissue formed on the articular surface of the defects. The repaired surface of the hydrogel implant was more compliant than normal articular cartilage throughout the 16 weeks following the operation, whereas the fibrous tissue that formed postoperatively over the empty defect was stiffer than normal articular cartilage after 5 weeks. This stiffness started to decrease 16 weeks after the operation, probably due to tissue degeneration. Thus, from the biomechanical and histological point of view, the hydrogel implant improved the articular surface repair.  (+info)

Evaluation of properties microcrystalline chitosan as a drug carrier. Part 1. In vitro release of diclofenac from mictocrystalline chitosan hydrogel. (5/453)

The influence of microcrystalline chitosan hydrogel, alone (MCCh) as well as in combination with methylcellulose (MC) or Carbopol (CP), on the release of diclofenac free acid (DA) and its salt (DS) was studied in vitro. Commercial Olfen gel (Mepha Ltd., Switzerland) was applied as a reference preparation. The influence of hydrophilizing agents (1,2-propylene glycol and glycerol) and methycellulose hydrogel on the rheological properties of the vehicle and on the release of drug from modified MCCh hydrogel was studied. The quantity of the released substance was determined by UV-spectroscopy. The results confirmed that release was dependent on the chemical character of the drug and on the type of vehicle. The process of diclofenac release from MCCh hydrogels as well as from Carbopol hydrogels runs in two phases. The first phase is characterised by rapid release whereas in the second phase the release is much slower. The most suitable basis for diclofenac is microcrystalline chitosan hydrogel with addition glycerol, 1,2-propylene glycol, and methylcellulose hydrogel.  (+info)

Improvement of transdermal permeation of captopril by iontophoresis. (6/453)

AIM: The feasibility of iontophoresis on the transdermal delivery of captopril was studied. METHODS: Iontophoresis was employed for enhancing transdermal transport of captopril through rat skin in vitro and in vivo. RESULTS: It was demonstrated that the iontophoresis-induced flux of captopril was affected by various factors such as pH, ionic concentration, and the concentration of captopril in donor compartments as well as the applied electric current intensity. Electric current could induce several-fold increase in captopril flux with hydrogel. Skin permeation study in vivo in rats demonstrated that iontophoresis could effectively promote the transdermal transport of captopril without significant skin irritation. Captopril concentration in plasma reached plateau (approximately 0.9 microgram/mL) at 1 h after current application and was maintained at the same level during the experiment. On the contrary, captopril could not be detected in plasma when the current was not applied. No obvious skin irritation was observed after 9-h continuous iontophoresis. CONCLUSION: Transdermal delivery of captopril can be effectively improved by iontopophoresis.  (+info)

Imaging of hydrogel episcleral buckle fragmentation as a late complication after retinal reattachment surgery. (7/453)

Hydrogel encircling bands were introduced in the early 1980s as a product that was superior to bands composed of silicone rubber or silicone sponge for the surgical treatment of retinal detachment. Late complications consisting of orbital swelling and diplopia requiring band removal began to be reported in the early 1990s. Pathologic studies of these expanded fragments of hydrogel material after removal showed in vivo hydrolysis with foreign body reaction and dystrophic calcification. We report the imaging findings in five patients in whom this late complication developed. Hydrogel fragmentation has a characteristic imaging appearance consisting of a circumferential orbital mass associated with rim enhancement. This appearance should prompt inquiries regarding previous scleral buckle procedures with hydrogel bands. Familiarity with this appearance will avoid misinterpretation and unwarranted biopsy before band removal.  (+info)

Cell traction forces on soft biomaterials. I. Microrheology of type I collagen gels. (8/453)

A laser-trap microrheometry technique was used to determine the local shear moduli of Type I collagen gels. Embedded 2.1 microm polystyrene latex particles were displaced 10-100 nm using a near-infrared laser trap with a trap constant of 0.0001 N/m. The trap was oscillated transversely +/- 200 nm using a refractive glass plate mounted on a galvanometric scanner. The displacement of the microspheres was in phase with the movement of the laser trap at frequencies less than 1 rad/s, indicating that at least locally, the gels behaved as elastic media. The local shear modulus was measured at various positions throughout the gel, and, for gels at 2.3 mg/mL and 37 degrees C, values ranged from G = 3 to 80 Pa. The average shear modulus G = 55 Pa, which compares well with measurements from parallel plate rheometry.  (+info)

A hydrogel is a biomaterial that is composed of a three-dimensional network of crosslinked polymers, which are able to absorb and retain a significant amount of water or biological fluids while maintaining their structure. Hydrogels are similar to natural tissues in their water content, making them suitable for various medical applications such as contact lenses, wound dressings, drug delivery systems, tissue engineering, and regenerative medicine.

Hydrogels can be synthesized from a variety of materials, including synthetic polymers like polyethylene glycol (PEG) or natural polymers like collagen, hyaluronic acid, or chitosan. The properties of hydrogels, such as their mechanical strength, degradation rate, and biocompatibility, can be tailored to specific applications by adjusting the type and degree of crosslinking, the molecular weight of the polymers, and the addition of functional groups or drugs.

Hydrogels have shown great potential in medical research and clinical practice due to their ability to mimic the natural environment of cells and tissues, provide sustained drug release, and promote tissue regeneration.

Hydrogels are defined in the medical and biomedical fields as cross-linked, hydrophilic polymer networks that have the ability to swell and retain a significant amount of water or biological fluids while maintaining their structure. They can be synthesized from natural, synthetic, or hybrid polymers.

Hydrogels are known for their biocompatibility, high water content, and soft consistency, which resemble natural tissues, making them suitable for various medical applications such as contact lenses, drug delivery systems, tissue engineering, wound dressing, and biosensors. The physical and chemical properties of hydrogels can be tailored to specific uses by adjusting the polymer composition, cross-linking density, and network structure.

Biocompatible materials are non-toxic and non-reacting substances that can be used in medical devices, tissue engineering, and drug delivery systems without causing harm or adverse reactions to living tissues or organs. These materials are designed to mimic the properties of natural tissues and are able to integrate with biological systems without being rejected by the body's immune system.

Biocompatible materials can be made from a variety of substances, including metals, ceramics, polymers, and composites. The specific properties of these materials, such as their mechanical strength, flexibility, and biodegradability, are carefully selected to meet the requirements of their intended medical application.

Examples of biocompatible materials include titanium used in dental implants and joint replacements, polyethylene used in artificial hips, and hydrogels used in contact lenses and drug delivery systems. The use of biocompatible materials has revolutionized modern medicine by enabling the development of advanced medical technologies that can improve patient outcomes and quality of life.

Hydrophilic contact lenses are a type of contact lens that is designed to absorb and retain water. These lenses are made from materials that have an affinity for water, which helps them to remain moist and comfortable on the eye. The water content of hydrophilic contact lenses can vary, but typically ranges from 30-80% by weight.

Hydrophilic contact lenses are often used to correct refractive errors such as myopia (nearsightedness), hyperopia (farsightedness), and astigmatism. They can be made in a variety of materials, including soft hydrogel and silicone hydrogel.

One advantage of hydrophilic contact lenses is that they tend to be more comfortable to wear than other types of contacts, as they retain moisture and conform closely to the shape of the eye. However, they may also be more prone to deposits and buildup, which can lead to protein accumulation and discomfort over time. Proper care and cleaning are essential to maintain the health of the eyes when wearing hydrophilic contact lenses.

Polyethylene glycols (PEGs) are a family of synthetic, water-soluble polymers with a wide range of molecular weights. They are commonly used in the medical field as excipients in pharmaceutical formulations due to their ability to improve drug solubility, stability, and bioavailability. PEGs can also be used as laxatives to treat constipation or as bowel cleansing agents prior to colonoscopy examinations. Additionally, some PEG-conjugated drugs have been developed for use in targeted cancer therapies.

In a medical context, PEGs are often referred to by their average molecular weight, such as PEG 300, PEG 400, PEG 1500, and so on. Higher molecular weight PEGs tend to be more viscous and have longer-lasting effects in the body.

It's worth noting that while PEGs are generally considered safe for use in medical applications, some people may experience allergic reactions or hypersensitivity to these compounds. Prolonged exposure to high molecular weight PEGs has also been linked to potential adverse effects, such as decreased fertility and developmental toxicity in animal studies. However, more research is needed to fully understand the long-term safety of PEGs in humans.

Tissue engineering is a branch of biomedical engineering that combines the principles of engineering, materials science, and biological sciences to develop functional substitutes for damaged or diseased tissues and organs. It involves the creation of living, three-dimensional structures that can restore, maintain, or improve tissue function. This is typically accomplished through the use of cells, scaffolds (biodegradable matrices), and biologically active molecules. The goal of tissue engineering is to develop biological substitutes that can ultimately restore normal function and structure in damaged tissues or organs.

Tissue scaffolds, also known as bioactive scaffolds or synthetic extracellular matrices, refer to three-dimensional structures that serve as templates for the growth and organization of cells in tissue engineering and regenerative medicine. These scaffolds are designed to mimic the natural extracellular matrix (ECM) found in biological tissues, providing a supportive environment for cell attachment, proliferation, differentiation, and migration.

Tissue scaffolds can be made from various materials, including naturally derived biopolymers (e.g., collagen, alginate, chitosan, hyaluronic acid), synthetic polymers (e.g., polycaprolactone, polylactic acid, poly(lactic-co-glycolic acid)), or a combination of both. The choice of material depends on the specific application and desired properties, such as biocompatibility, biodegradability, mechanical strength, and porosity.

The primary functions of tissue scaffolds include:

1. Cell attachment: Providing surfaces for cells to adhere, spread, and form stable focal adhesions.
2. Mechanical support: Offering a structural framework that maintains the desired shape and mechanical properties of the engineered tissue.
3. Nutrient diffusion: Ensuring adequate transport of nutrients, oxygen, and waste products throughout the scaffold to support cell survival and function.
4. Guided tissue growth: Directing the organization and differentiation of cells through spatial cues and biochemical signals.
5. Biodegradation: Gradually degrading at a rate that matches tissue regeneration, allowing for the replacement of the scaffold with native ECM produced by the cells.

Tissue scaffolds have been used in various applications, such as wound healing, bone and cartilage repair, cardiovascular tissue engineering, and neural tissue regeneration. The design and fabrication of tissue scaffolds are critical aspects of tissue engineering, aiming to create functional substitutes for damaged or diseased tissues and organs.

I'm sorry for any confusion, but "Polyvinyl Alcohol" is not a medical term. It is a chemical compound used in various industrial and commercial applications, including the production of adhesives, paints, and medical devices. Polyvinyl Alcohol is a type of synthetic polymer made from the polymerization of vinyl acetate monomer, followed by alcoholysis to replace the acetate groups with hydroxyl groups.

In a medical context, Polyvinyl Alcohol might be used in certain medical devices or applications, such as contact lenses, eye drops, and drug delivery systems, due to its biocompatibility and resistance to protein absorption. However, it is not a term commonly used to describe a medical condition or treatment.

Hexuronic acids are a type of uronic acid that contains six carbon atoms and is commonly found in various biological tissues and polysaccharides, such as pectins, heparin, and certain glycoproteins. The most common hexuronic acids are glucuronic acid and iduronic acid, which are formed from the oxidation of the corresponding hexoses, glucose and galactose, respectively. Hexuronic acids play important roles in various biological processes, including the detoxification and excretion of xenobiotics, the formation of proteoglycans, and the regulation of cell growth and differentiation.

I'm happy to help! However, I must clarify that "materials testing" is not a medical term per se. It is a term used in various fields, including engineering and materials science, to describe the process of subjecting materials to different tests to evaluate their properties and performance under various conditions.

In the context of medical devices or implants, materials testing may refer to the evaluation of the physical and mechanical properties of materials used in their construction. These tests can include assessments of strength, durability, biocompatibility, and other factors that are critical to ensuring the safety and efficacy of medical devices.

Medical device manufacturers must comply with regulatory standards for materials testing to ensure that their products meet specific requirements for performance, safety, and quality. These standards may vary depending on the type of device, its intended use, and the country or region in which it will be marketed and sold.

Glucuronic acid is a physiological important organic acid, which is a derivative of glucose. It is formed by the oxidation of the primary alcohol group of glucose to form a carboxyl group at the sixth position. Glucuronic acid plays a crucial role in the detoxification process in the body as it conjugates with toxic substances, making them water-soluble and facilitating their excretion through urine or bile. This process is known as glucuronidation. It is also a component of various polysaccharides, such as heparan sulfate and chondroitin sulfate, which are found in the extracellular matrix of connective tissues.

Gelatin is not strictly a medical term, but it is often used in medical contexts. Medically, gelatin is recognized as a protein-rich substance that is derived from collagen, which is found in the skin, bones, and connective tissue of animals. It is commonly used in the production of various medical and pharmaceutical products such as capsules, wound dressings, and drug delivery systems due to its biocompatibility and ability to form gels.

In a broader sense, gelatin is a translucent, colorless, flavorless food ingredient that is derived from collagen through a process called hydrolysis. It is widely used in the food industry as a gelling agent, thickener, stabilizer, and texturizer in various foods such as candies, desserts, marshmallows, and yogurts.

It's worth noting that while gelatin has many uses, it may not be suitable for vegetarians or those with dietary restrictions since it is derived from animal products.

Alginates are a type of polysaccharide derived from brown algae or produced synthetically, which have gelling and thickening properties. In medical context, they are commonly used as a component in wound dressings, dental impressions, and bowel cleansing products. The gels formed by alginates can provide a protective barrier to wounds, help maintain a moist environment, and promote healing. They can also be used to create a mold of the mouth or other body parts in dental and medical applications. In bowel cleansing, sodium alginates are often combined with sodium bicarbonate and water to form a solution that expands and stimulates bowel movements, helping to prepare the colon for procedures such as colonoscopy.

Silicones are not a medical term, but they are commonly used in the medical field, particularly in medical devices and healthcare products. Silicones are synthetic polymers made up of repeating units of siloxane, which is a chain of alternating silicon and oxygen atoms. They can exist in various forms such as oils, gels, rubbers, and resins.

In the medical context, silicones are often used for their unique properties, including:

1. Biocompatibility - Silicones have a low risk of causing an adverse reaction when they come into contact with living tissue.
2. Inertness - They do not react chemically with other substances, making them suitable for use in medical devices that need to remain stable over time.
3. Temperature resistance - Silicones can maintain their flexibility and elasticity even under extreme temperature conditions.
4. Gas permeability - Some silicone materials allow gases like oxygen and water vapor to pass through, which is useful in applications where maintaining a moist environment is essential.
5. Durability - Silicones have excellent resistance to aging, weathering, and environmental factors, ensuring long-lasting performance.

Examples of medical applications for silicones include:

1. Breast implants
2. Contact lenses
3. Catheters
4. Artificial joints and tendons
5. Bandages and wound dressings
6. Drug delivery systems
7. Medical adhesives
8. Infant care products (nipples, pacifiers)

Extended-wear contact lenses are a type of contact lens that is designed to be worn continuously, including during sleep, for an extended period of time. These lenses are typically made from materials that allow more oxygen to reach the eye, reducing the risk of eye irritation and infection compared to traditional overnight wear of non-extended wear lenses.

Extended-wear contact lenses can be worn for up to 30 days or longer, depending on the specific lens material and the individual's tolerance. However, it is important to note that even extended-wear contacts come with some risks, including a higher risk of eye infections and corneal ulcers compared to daily wear lenses. Therefore, it is essential to follow the recommended wearing schedule and replacement schedule provided by an eye care professional, as well as to have regular eye exams to monitor the health of the eyes.

Acrylic resins are a type of synthetic polymer made from methacrylate monomers. They are widely used in various industrial, commercial, and medical applications due to their unique properties such as transparency, durability, resistance to breakage, and ease of coloring or molding. In the medical field, acrylic resins are often used to make dental restorations like false teeth and fillings, medical devices like intraocular lenses, and surgical instruments. They can also be found in orthopedic implants, bone cement, and other medical-grade plastics. Acrylic resins are biocompatible, meaning they do not typically cause adverse reactions when in contact with living tissue. However, they may release small amounts of potentially toxic chemicals over time, so their long-term safety in certain applications is still a subject of ongoing research.

Polyhydroxyethyl Methacrylate (PHEMA) is not a medical term itself, but a chemical compound that is used in various medical and biomedical applications. Therefore, I will provide you with a chemical definition of PHEMA:

Polyhydroxyethyl Methacrylate (PHEMA) is a type of synthetic hydrogel, which is a cross-linked polymer network with the ability to absorb and retain significant amounts of water or biological fluids. It is made by polymerizing the methacrylate monomer, hydroxyethyl methacrylate (HEMA), in the presence of a crosslinking agent. The resulting PHEMA material has excellent biocompatibility, making it suitable for various medical applications such as contact lenses, drug delivery systems, artificial cartilage, and wound dressings.

Poloxamers are a type of triblock copolymer made up of a central hydrophobic chain of polyoxypropylene (poly(propylene oxide)) flanked by two hydrophilic chains of polyoxyethylene (poly(ethylene oxide)). They are amphiphilic molecules, meaning they have both hydrophilic and hydrophobic parts.

Poloxamers are often used in the pharmaceutical industry as drug delivery agents, emulsifiers, solubilizers, and stabilizers. They can form micelles in aqueous solutions above their critical micelle concentration (CMC), with the hydrophobic chains oriented toward the interior of the micelle and the hydrophilic chains on the exterior, interacting with the water molecules. This unique property allows poloxamers to solubilize drugs that are otherwise poorly soluble in water, improving their bioavailability.

Poloxamers have been studied for various medical applications, including as drug carriers for chemotherapy, diagnostic agents, and mucoadhesive materials. Some specific poloxamer compounds have been approved by the FDA for use in pharmaceutical formulations, such as Poloxamer 188 and Poloxamer 407.

In a medical context, poloxamers are not typically used as standalone treatments but rather as components of drug delivery systems or formulations.

Acrylamides are a type of chemical that can form in some foods during high-temperature cooking processes, such as frying, roasting, and baking. They are created when certain amino acids (asparagine) and sugars in the food react together at temperatures above 120°C (248°F). This reaction is known as the Maillard reaction.

Acrylamides have been classified as a probable human carcinogen by the International Agency for Research on Cancer (IARC), based on studies in animals. However, more research is needed to fully understand the potential health risks associated with acrylamide exposure from food.

Public health organizations recommend limiting acrylamide intake by following some cooking practices such as:

* Avoiding overcooking or burning foods
* Soaking potatoes (which are high in asparagine) in water before frying to reduce the formation of acrylamides
* Choosing raw, unprocessed, or minimally processed foods when possible.

"Immobilized cells" is a term used in biotechnology and cell biology to describe situations where living cells are confined or restricted in their movement within a defined space. This can be achieved through various methods such as entrapment within a gel, adsorption onto a surface, or encapsulation within a semi-permeable membrane. The immobilization of cells allows for their repeated use in biochemical reactions, such as fermentation or waste treatment, while also providing stability and ease of separation from the reaction products. Additionally, immobilized cells can be used to study cellular processes and functions under controlled conditions.

I'm sorry for any confusion, but "Polyesters" is not a medical term. It is a term used in materials science and textile industry to describe a type of synthetic fiber made from polymers characterized by the presence of ester groups in their main chain. If you have any questions related to medical terminology or concepts, I'd be happy to help with those instead!

Rheology is not a term that is specific to medicine, but rather it is a term used in the field of physics to describe the flow and deformation of matter. It specifically refers to the study of how materials flow or deform under various stresses or strains. This concept can be applied to various medical fields such as studying the flow properties of blood (hematology), understanding the movement of tissues and organs during surgical procedures, or analyzing the mechanical behavior of biological materials like bones and cartilages.

Contact lenses are thin, curved plastic or silicone hydrogel devices that are placed on the eye to correct vision, replace a missing or damaged cornea, or for cosmetic purposes. They rest on the surface of the eye, called the cornea, and conform to its shape. Contact lenses are designed to float on a thin layer of tears and move with each blink.

There are two main types of contact lenses: soft and rigid gas permeable (RGP). Soft contact lenses are made of flexible hydrophilic (water-absorbing) materials that allow oxygen to pass through the lens to the cornea. RGP lenses are made of harder, more oxygen-permeable materials.

Contact lenses can be used to correct various vision problems, including nearsightedness, farsightedness, astigmatism, and presbyopia. They come in different shapes, sizes, and powers to suit individual needs and preferences. Proper care, handling, and regular check-ups with an eye care professional are essential for maintaining good eye health and preventing complications associated with contact lens wear.

In the context of medical terminology, "porosity" is not a term that is frequently used to describe human tissues or organs. However, in dermatology and cosmetics, porosity refers to the ability of the skin to absorb and retain moisture or topical treatments.

A skin with high porosity has larger pores and can absorb more products, while a skin with low porosity has smaller pores and may have difficulty absorbing products. It is important to note that this definition of porosity is not a medical one but is instead used in the beauty industry.

Microspheres are tiny, spherical particles that range in size from 1 to 1000 micrometers in diameter. They are made of biocompatible and biodegradable materials such as polymers, glass, or ceramics. In medical terms, microspheres have various applications, including drug delivery systems, medical imaging, and tissue engineering.

In drug delivery, microspheres can be used to encapsulate drugs and release them slowly over time, improving the efficacy of the treatment while reducing side effects. They can also be used for targeted drug delivery, where the microspheres are designed to accumulate in specific tissues or organs.

In medical imaging, microspheres can be labeled with radioactive isotopes or magnetic materials and used as contrast agents to enhance the visibility of tissues or organs during imaging procedures such as X-ray, CT, MRI, or PET scans.

In tissue engineering, microspheres can serve as a scaffold for cell growth and differentiation, promoting the regeneration of damaged tissues or organs. Overall, microspheres have great potential in various medical applications due to their unique properties and versatility.

Acrylates are a group of chemical compounds that are derived from acrylic acid. They are commonly used in various industrial and commercial applications, including the production of plastics, resins, paints, and adhesives. In the medical field, acrylates are sometimes used in the formation of dental restorations, such as fillings and dentures, due to their strong bonding properties and durability.

However, it is important to note that some people may have allergic reactions or sensitivities to acrylates, which can cause skin irritation, allergic contact dermatitis, or other adverse effects. Therefore, medical professionals must use caution when working with these materials and ensure that patients are informed of any potential risks associated with their use.

Chitosan is a complex carbohydrate that is derived from the exoskeletons of crustaceans, such as shrimp and crabs. It is made up of chains of N-acetyl-d-glucosamine and d-glucosamine units. Chitosan has been studied for its potential medical and health benefits, including its ability to lower cholesterol levels, promote weight loss, and help control blood sugar levels. It is also used in wound care products due to its antibacterial and absorbent properties. However, more research is needed to confirm these potential benefits and establish recommended dosages and safety guidelines.

I couldn't find a medical definition specifically for "delayed-action preparations." However, in the context of pharmacology, it may refer to medications or treatments that have a delayed onset of action. These are designed to release the active drug slowly over an extended period, which can help to maintain a consistent level of the medication in the body and reduce the frequency of dosing.

Examples of delayed-action preparations include:

1. Extended-release (ER) or controlled-release (CR) formulations: These are designed to release the drug slowly over several hours, reducing the need for frequent dosing. Examples include extended-release tablets and capsules.
2. Transdermal patches: These deliver medication through the skin and can provide a steady rate of drug delivery over several days. Examples include nicotine patches for smoking cessation or fentanyl patches for pain management.
3. Injectable depots: These are long-acting injectable formulations that slowly release the drug into the body over weeks to months. An example is the use of long-acting antipsychotic injections for the treatment of schizophrenia.
4. Implantable devices: These are small, biocompatible devices placed under the skin or within a body cavity that release a steady dose of medication over an extended period. Examples include hormonal implants for birth control or drug-eluting stents used in cardiovascular procedures.

Delayed-action preparations can improve patient compliance and quality of life by reducing dosing frequency, minimizing side effects, and maintaining consistent therapeutic levels.

The Elastic Modulus, also known as Young's modulus, is a measure of the stiffness of a material. It is defined as the ratio of stress (force per unit area) to strain (partial deformation or change in length per unit length) in the elastic range of deformation of a material. In other words, it measures how much a material will deform (change in length or size) when subjected to a given amount of force. A higher elastic modulus indicates that a material is stiffer and less likely to deform, while a lower elastic modulus indicates that a material is more flexible and will deform more easily. The elastic modulus is typically expressed in units of Pascals (Pa) or Gigapascals (GPa).

Methacrylates are a group of chemical compounds that contain the methacrylate functional group, which is a vinyl group (CH2=CH-) with a carbonyl group (C=O) at the β-position. This structure gives them unique chemical and physical properties, such as low viscosity, high reactivity, and resistance to heat and chemicals.

In medical terms, methacrylates are used in various biomedical applications, such as dental restorative materials, bone cements, and drug delivery systems. For example, methacrylate-based resins are commonly used in dentistry for fillings, crowns, and bridges due to their excellent mechanical properties and adhesion to tooth structures.

However, there have been concerns about the potential toxicity of methacrylates, particularly their ability to release monomers that can cause allergic reactions, irritation, or even mutagenic effects in some individuals. Therefore, it is essential to use these materials with caution and follow proper handling and safety protocols.

I'm sorry for any confusion, but "mechanical phenomena" is not a standard medical term. The term "mechanical phenomenon" is more commonly used in the fields of physics and engineering to refer to events or processes that involve physical forces and movements, such as the movement of a lever or the flow of a fluid due to pressure differences.

If you have any questions about a specific medical concept or condition, I would be happy to try to help you with that instead!

Hydrocolloid bandages are a type of dressing used in wound care. They consist of an outer waterproof layer and an inner hydrophilic layer made of materials such as gelatin, pectin, or carboxymethylcellulose. When the bandage comes into contact with moisture from the wound, it forms a gel that helps to maintain a moist environment, which can promote healing.

Hydrocolloid bandages are useful for managing a variety of wound types, including partial-thickness burns, pressure ulcers, and diabetic foot ulcers. They can help to protect the wound from external contaminants, reduce pain and discomfort, and provide sustained release of medications such as analgesics or antibiotics.

One advantage of hydrocolloid bandages is that they can be left in place for several days at a time, which can reduce the frequency of dressing changes and minimize trauma to the wound bed. However, it's important to monitor the wound regularly to ensure that it is healing properly and to check for signs of infection or other complications.

Hyaluronic acid is a glycosaminoglycan, a type of complex carbohydrate, that is naturally found in the human body. It is most abundant in the extracellular matrix of soft connective tissues, including the skin, eyes, and joints. Hyaluronic acid is known for its remarkable capacity to retain water, which helps maintain tissue hydration, lubrication, and elasticity. Its functions include providing structural support, promoting wound healing, and regulating cell growth and differentiation. In the medical field, hyaluronic acid is often used in various forms as a therapeutic agent for conditions like osteoarthritis, dry eye syndrome, and skin rejuvenation.

Cell culture is a technique used in scientific research to grow and maintain cells from plants, animals, or humans in a controlled environment outside of their original organism. This environment typically consists of a sterile container called a cell culture flask or plate, and a nutrient-rich liquid medium that provides the necessary components for the cells' growth and survival, such as amino acids, vitamins, minerals, and hormones.

There are several different types of cell culture techniques used in research, including:

1. Adherent cell culture: In this technique, cells are grown on a flat surface, such as the bottom of a tissue culture dish or flask. The cells attach to the surface and spread out, forming a monolayer that can be observed and manipulated under a microscope.
2. Suspension cell culture: In suspension culture, cells are grown in liquid medium without any attachment to a solid surface. These cells remain suspended in the medium and can be agitated or mixed to ensure even distribution of nutrients.
3. Organoid culture: Organoids are three-dimensional structures that resemble miniature organs and are grown from stem cells or other progenitor cells. They can be used to study organ development, disease processes, and drug responses.
4. Co-culture: In co-culture, two or more different types of cells are grown together in the same culture dish or flask. This technique is used to study cell-cell interactions and communication.
5. Conditioned medium culture: In this technique, cells are grown in a medium that has been conditioned by previous cultures of other cells. The conditioned medium contains factors secreted by the previous cells that can influence the growth and behavior of the new cells.

Cell culture techniques are widely used in biomedical research to study cellular processes, develop drugs, test toxicity, and investigate disease mechanisms. However, it is important to note that cell cultures may not always accurately represent the behavior of cells in a living organism, and results from cell culture experiments should be validated using other methods.

Nanofibers are defined in the medical field as fibrous structures with extremely small diameters, typically measuring between 100 nanometers to 1 micrometer. They can be made from various materials such as polymers, ceramics, or composites and have a high surface area-to-volume ratio, which makes them useful in a variety of biomedical applications. These include tissue engineering, drug delivery, wound healing, and filtration. Nanofibers can be produced using different techniques such as electrospinning, self-assembly, and phase separation.

Drug delivery systems (DDS) refer to techniques or technologies that are designed to improve the administration of a pharmaceutical compound in terms of its efficiency, safety, and efficacy. A DDS can modify the drug release profile, target the drug to specific cells or tissues, protect the drug from degradation, and reduce side effects.

The goal of a DDS is to optimize the bioavailability of a drug, which is the amount of the drug that reaches the systemic circulation and is available at the site of action. This can be achieved through various approaches, such as encapsulating the drug in a nanoparticle or attaching it to a biomolecule that targets specific cells or tissues.

Some examples of DDS include:

1. Controlled release systems: These systems are designed to release the drug at a controlled rate over an extended period, reducing the frequency of dosing and improving patient compliance.
2. Targeted delivery systems: These systems use biomolecules such as antibodies or ligands to target the drug to specific cells or tissues, increasing its efficacy and reducing side effects.
3. Nanoparticle-based delivery systems: These systems use nanoparticles made of polymers, lipids, or inorganic materials to encapsulate the drug and protect it from degradation, improve its solubility, and target it to specific cells or tissues.
4. Biodegradable implants: These are small devices that can be implanted under the skin or into body cavities to deliver drugs over an extended period. They can be made of biodegradable materials that gradually break down and release the drug.
5. Inhalation delivery systems: These systems use inhalers or nebulizers to deliver drugs directly to the lungs, bypassing the digestive system and improving bioavailability.

Overall, DDS play a critical role in modern pharmaceutical research and development, enabling the creation of new drugs with improved efficacy, safety, and patient compliance.

Biomimetic materials are synthetic or natural substances that mimic the chemical, physical, and biological properties of living systems or tissues. These materials are designed to interact with cells, tissues, and organs in ways that resemble the body's own structures and processes. They can be used in a variety of medical applications, including tissue engineering, drug delivery, and medical devices.

Biomimetic materials may be composed of polymers, ceramics, metals, or composites, and they can be designed to have specific properties such as mechanical strength, biocompatibility, and degradability. They may also incorporate bioactive molecules, such as growth factors or drugs, to promote healing or prevent infection.

The goal of using biomimetic materials is to create medical solutions that are more effective, safer, and more compatible with the body than traditional synthetic materials. By mimicking the body's own structures and processes, these materials can help to reduce inflammation, promote tissue regeneration, and improve overall patient outcomes.

Contact lens solutions are a type of disinfecting and cleaning solution specifically designed for use with contact lenses. They typically contain a combination of chemicals, such as preservatives, disinfectants, and surfactants, that work together to clean, disinfect, and store contact lenses safely and effectively.

There are several types of contact lens solutions available, including:

1. Multipurpose solution: This type of solution is the most commonly used and can be used for cleaning, rinsing, disinfecting, and storing soft contact lenses. It contains a combination of ingredients that perform all these functions in one step.
2. Hydrogen peroxide solution: This type of solution contains hydrogen peroxide as the main active ingredient, which is a powerful disinfectant. However, it requires a special case called a neutralizer to convert the hydrogen peroxide into water and oxygen before using the lenses.
3. Saline solution: This type of solution is used only for rinsing and storing contact lenses and does not contain any disinfecting or cleaning agents. It is often used in combination with other solutions for a complete contact lens care routine.
4. Daily cleaner: This type of solution is used to remove protein buildup and other deposits from the surface of contact lenses. It should be used in conjunction with a multipurpose or hydrogen peroxide solution as part of a daily cleaning routine.

It's important to follow the manufacturer's instructions carefully when using contact lens solutions to ensure that they are used safely and effectively. Failure to do so could result in eye irritation, infection, or other complications.

An injection is a medical procedure in which a medication, vaccine, or other substance is introduced into the body using a needle and syringe. The substance can be delivered into various parts of the body, including into a vein (intravenous), muscle (intramuscular), under the skin (subcutaneous), or into the spinal canal (intrathecal or spinal).

Injections are commonly used to administer medications that cannot be taken orally, have poor oral bioavailability, need to reach the site of action quickly, or require direct delivery to a specific organ or tissue. They can also be used for diagnostic purposes, such as drawing blood samples (venipuncture) or injecting contrast agents for imaging studies.

Proper technique and sterile conditions are essential when administering injections to prevent infection, pain, and other complications. The choice of injection site depends on the type and volume of the substance being administered, as well as the patient's age, health status, and personal preferences.

A drug carrier, also known as a drug delivery system or vector, is a vehicle that transports a pharmaceutical compound to a specific site in the body. The main purpose of using drug carriers is to improve the efficacy and safety of drugs by enhancing their solubility, stability, bioavailability, and targeted delivery, while minimizing unwanted side effects.

Drug carriers can be made up of various materials, including natural or synthetic polymers, lipids, inorganic nanoparticles, or even cells and viruses. They can encapsulate, adsorb, or conjugate drugs through different mechanisms, such as physical entrapment, electrostatic interaction, or covalent bonding.

Some common types of drug carriers include:

1. Liposomes: spherical vesicles composed of one or more lipid bilayers that can encapsulate hydrophilic and hydrophobic drugs.
2. Polymeric nanoparticles: tiny particles made of biodegradable polymers that can protect drugs from degradation and enhance their accumulation in target tissues.
3. Dendrimers: highly branched macromolecules with a well-defined structure and size that can carry multiple drug molecules and facilitate their release.
4. Micelles: self-assembled structures formed by amphiphilic block copolymers that can solubilize hydrophobic drugs in water.
5. Inorganic nanoparticles: such as gold, silver, or iron oxide nanoparticles, that can be functionalized with drugs and targeting ligands for diagnostic and therapeutic applications.
6. Cell-based carriers: living cells, such as red blood cells, stem cells, or immune cells, that can be loaded with drugs and used to deliver them to specific sites in the body.
7. Viral vectors: modified viruses that can infect cells and introduce genetic material encoding therapeutic proteins or RNA interference molecules.

The choice of drug carrier depends on various factors, such as the physicochemical properties of the drug, the route of administration, the target site, and the desired pharmacokinetics and biodistribution. Therefore, selecting an appropriate drug carrier is crucial for achieving optimal therapeutic outcomes and minimizing side effects.

Scanning electron microscopy (SEM) is a type of electron microscopy that uses a focused beam of electrons to scan the surface of a sample and produce a high-resolution image. In SEM, a beam of electrons is scanned across the surface of a specimen, and secondary electrons are emitted from the sample due to interactions between the electrons and the atoms in the sample. These secondary electrons are then detected by a detector and used to create an image of the sample's surface topography. SEM can provide detailed images of the surface of a wide range of materials, including metals, polymers, ceramics, and biological samples. It is commonly used in materials science, biology, and electronics for the examination and analysis of surfaces at the micro- and nanoscale.

In the context of medical definitions, polymers are large molecules composed of repeating subunits called monomers. These long chains of monomers can have various structures and properties, depending on the type of monomer units and how they are linked together. In medicine, polymers are used in a wide range of applications, including drug delivery systems, medical devices, and tissue engineering scaffolds. Some examples of polymers used in medicine include polyethylene, polypropylene, polystyrene, polyvinyl chloride (PVC), and biodegradable polymers such as polylactic acid (PLA) and polycaprolactone (PCL).

Silicone elastomers are a type of synthetic rubber made from silicone, which is a polymer composed primarily of silicon-oxygen bonds. They are known for their durability, flexibility, and resistance to heat, cold, and moisture. Silicone elastomers can be manufactured in various forms, including liquids, gels, and solids, and they are used in a wide range of medical applications such as:

1. Breast implants: Silicone elastomer shells filled with silicone gel are commonly used for breast augmentation and reconstruction.
2. Contact lenses: Some contact lenses are made from silicone elastomers due to their high oxygen permeability, which allows for better eye health.
3. Catheters: Silicone elastomer catheters are flexible and resistant to kinking, making them suitable for long-term use in various medical procedures.
4. Implantable drug delivery systems: Silicone elastomers can be used as a matrix for controlled release of drugs, allowing for sustained and targeted medication administration.
5. Medical adhesives: Silicone elastomer adhesives are biocompatible and can be used to attach medical devices to the skin or other tissues.
6. Sealants and coatings: Silicone elastomers can be used as sealants and coatings in medical devices to prevent leakage, improve durability, and reduce infection risk.

It is important to note that while silicone elastomers are generally considered safe for medical use, there have been concerns about the potential health risks associated with breast implants, such as capsular contracture, breast pain, and immune system reactions. However, these risks vary depending on the individual's health status and the specific type of silicone elastomer used.

Absorbable implants are medical devices that are designed to be placed inside the body during a surgical procedure, where they provide support, stabilization, or other functions, and then gradually break down and are absorbed by the body over time. These implants are typically made from materials such as polymers, proteins, or ceramics that have been engineered to degrade at a controlled rate, allowing them to be resorbed and eliminated from the body without the need for a second surgical procedure to remove them.

Absorbable implants are often used in orthopedic, dental, and plastic surgery applications, where they can help promote healing and support tissue regeneration. For example, absorbable screws or pins may be used to stabilize fractured bones during the healing process, after which they will gradually dissolve and be absorbed by the body. Similarly, absorbable membranes may be used in dental surgery to help guide the growth of new bone and gum tissue around an implant, and then be resorbed over time.

It's important to note that while absorbable implants offer several advantages over non-absorbable materials, such as reduced risk of infection and improved patient comfort, they may also have some limitations. For example, the mechanical properties of absorbable materials may not be as strong as those of non-absorbable materials, which could affect their performance in certain applications. Additionally, the degradation products of absorbable implants may cause local inflammation or other adverse reactions in some patients. As with any medical device, the use of absorbable implants should be carefully considered and discussed with a qualified healthcare professional.

Mesenchymal Stromal Cells (MSCs) are a type of adult stem cells found in various tissues, including bone marrow, adipose tissue, and umbilical cord blood. They have the ability to differentiate into multiple cell types, such as osteoblasts, chondrocytes, and adipocytes, under specific conditions. MSCs also possess immunomodulatory properties, making them a promising tool in regenerative medicine and therapeutic strategies for various diseases, including autoimmune disorders and tissue injuries. It is important to note that the term "Mesenchymal Stem Cells" has been replaced by "Mesenchymal Stromal Cells" in the scientific community to better reflect their biological characteristics and potential functions.

Cross-linking reagents are chemical agents that are used to create covalent bonds between two or more molecules, creating a network of interconnected molecules known as a cross-linked structure. In the context of medical and biological research, cross-linking reagents are often used to stabilize protein structures, study protein-protein interactions, and develop therapeutic agents.

Cross-linking reagents work by reacting with functional groups on adjacent molecules, such as amino groups (-NH2) or sulfhydryl groups (-SH), to form a covalent bond between them. This can help to stabilize protein structures and prevent them from unfolding or aggregating.

There are many different types of cross-linking reagents, each with its own specificity and reactivity. Some common examples include glutaraldehyde, formaldehyde, disuccinimidyl suberate (DSS), and bis(sulfosuccinimidyl) suberate (BS3). The choice of cross-linking reagent depends on the specific application and the properties of the molecules being cross-linked.

It is important to note that cross-linking reagents can also have unintended effects, such as modifying or disrupting the function of the proteins they are intended to stabilize. Therefore, it is essential to use them carefully and with appropriate controls to ensure accurate and reliable results.

Viscosity is a physical property of a fluid that describes its resistance to flow. In medical terms, viscosity is often discussed in relation to bodily fluids such as blood or synovial fluid (found in joints). The unit of measurement for viscosity is the poise, although it is more commonly expressed in millipascals-second (mPa.s) in SI units. Highly viscous fluids flow more slowly than less viscous fluids. Changes in the viscosity of bodily fluids can have significant implications for health and disease; for example, increased blood viscosity has been associated with cardiovascular diseases, while decreased synovial fluid viscosity can contribute to joint pain and inflammation in conditions like osteoarthritis.

Sodium benzoate is a chemical compound with the formula NaC7H5O2. It is a white crystalline powder that is readily soluble in water and alcohol. Sodium benzoate is a preservative commonly added to foods, beverages, and pharmaceuticals to inhibit microbial growth.

In medical terms, sodium benzoate may also be used as a medication to treat certain metabolic disorders such as hyperammonemia, which can occur in conditions like urea cycle disorders or liver disease. In these cases, sodium benzoate acts by binding with excess ammonia in the body and converting it into a compound that can be excreted through the kidneys.

It is important to note that people with a rare genetic disorder called benzoic aciduria should avoid foods or medications containing sodium benzoate, as they are unable to metabolize this compound properly.

Tissue adhesives, also known as surgical glues or tissue sealants, are medical devices used to approximate and hold together tissues or wounds in place of traditional sutures or staples. They work by creating a bond between the tissue surfaces, helping to promote healing and reduce the risk of infection. Tissue adhesives can be synthetic or biologically derived and are often used in various surgical procedures, including ophthalmic, dermatological, and pediatric surgeries. Some common types of tissue adhesives include cyanoacrylate-based glues, fibrin sealants, and collagen-based sealants.

Biofouling is the accumulation of microorganisms, algae, plants, and animals on wet surfaces, such as the hulls of ships, pier pilings, and buoys. This growth can have negative impacts on the performance and efficiency of equipment and infrastructure, leading to increased maintenance costs and potential environmental damage. In the medical field, biofouling can also refer to the undesirable accumulation of microorganisms or biomolecules on medical devices, which can lead to infection or device failure.

Biomimetics, also known as biomimicry, is the process of mimicking or taking inspiration from nature and biological systems to design materials, structures, or processes that solve human problems. It involves studying the models, systems, and elements of nature and then applying the knowledge gained to create new technologies and solutions.

In a medical context, biomimetics can be used to develop new therapies, medical devices, and diagnostic tools. For example, researchers might look to the structure of a spider's web to design a better surgical mesh or take inspiration from the way a gecko sticks to surfaces to create a new type of adhesive bandage.

Biomimetics is an interdisciplinary field that draws on knowledge from biology, chemistry, physics, engineering, and materials science. It has the potential to lead to innovative solutions in healthcare, sustainability, energy, transportation, and other areas.

In the context of medical and health sciences, particle size generally refers to the diameter or dimension of particles, which can be in the form of solid particles, droplets, or aerosols. These particles may include airborne pollutants, pharmaceutical drugs, or medical devices such as nanoparticles used in drug delivery systems.

Particle size is an important factor to consider in various medical applications because it can affect the behavior and interactions of particles with biological systems. For example, smaller particle sizes can lead to greater absorption and distribution throughout the body, while larger particle sizes may be filtered out by the body's natural defense mechanisms. Therefore, understanding particle size and its implications is crucial for optimizing the safety and efficacy of medical treatments and interventions.

Experimental implants refer to medical devices that are not yet approved by regulatory authorities for general use in medical practice. These are typically being tested in clinical trials to evaluate their safety and efficacy. The purpose of experimental implants is to determine whether they can be used as a viable treatment option for various medical conditions. They may include, but are not limited to, devices such as artificial joints, heart valves, or spinal cord stimulators that are still in the developmental or testing stage. Participation in clinical trials involving experimental implants is voluntary and usually requires informed consent from the patient.

A bandage is a medical dressing or covering applied to a wound, injury, or sore with the intention of promoting healing or preventing infection. Bandages can be made of a variety of materials such as gauze, cotton, elastic, or adhesive tape and come in different sizes and shapes to accommodate various body parts. They can also have additional features like fasteners, non-slip surfaces, or transparent windows for monitoring the condition of the wound.

Bandages serve several purposes, including:

1. Absorbing drainage or exudate from the wound
2. Protecting the wound from external contaminants and bacteria
3. Securing other medical devices such as catheters or splints in place
4. Reducing swelling or promoting immobilization of the affected area
5. Providing compression to control bleeding or prevent fluid accumulation
6. Relieving pain by reducing pressure on sensitive nerves or structures.

Proper application and care of bandages are essential for effective wound healing and prevention of complications such as infection or delayed recovery.

Cell survival refers to the ability of a cell to continue living and functioning normally, despite being exposed to potentially harmful conditions or treatments. This can include exposure to toxins, radiation, chemotherapeutic drugs, or other stressors that can damage cells or interfere with their normal processes.

In scientific research, measures of cell survival are often used to evaluate the effectiveness of various therapies or treatments. For example, researchers may expose cells to a particular drug or treatment and then measure the percentage of cells that survive to assess its potential therapeutic value. Similarly, in toxicology studies, measures of cell survival can help to determine the safety of various chemicals or substances.

It's important to note that cell survival is not the same as cell proliferation, which refers to the ability of cells to divide and multiply. While some treatments may promote cell survival, they may also inhibit cell proliferation, making them useful for treating diseases such as cancer. Conversely, other treatments may be designed to specifically target and kill cancer cells, even if it means sacrificing some healthy cells in the process.

Surface properties in the context of medical science refer to the characteristics and features of the outermost layer or surface of a biological material or structure, such as cells, tissues, organs, or medical devices. These properties can include physical attributes like roughness, smoothness, hydrophobicity or hydrophilicity, and electrical conductivity, as well as chemical properties like charge, reactivity, and composition.

In the field of biomaterials science, understanding surface properties is crucial for designing medical implants, devices, and drug delivery systems that can interact safely and effectively with biological tissues and fluids. Surface modifications, such as coatings or chemical treatments, can be used to alter surface properties and enhance biocompatibility, improve lubricity, reduce fouling, or promote specific cellular responses like adhesion, proliferation, or differentiation.

Similarly, in the field of cell biology, understanding surface properties is essential for studying cell-cell interactions, cell signaling, and cell behavior. Cells can sense and respond to changes in their environment, including variations in surface properties, which can influence cell shape, motility, and function. Therefore, characterizing and manipulating surface properties can provide valuable insights into the mechanisms of cellular processes and offer new strategies for developing therapies and treatments for various diseases.

Skin physiological processes refer to the functions and changes that occur in the skin, which are necessary for its maintenance, repair, and regulation of body homeostasis. These processes include:

1. Barrier Function: The skin forms a physical barrier that protects the body from external factors such as microorganisms, chemicals, and UV radiation. It also helps to prevent water loss from the body.
2. Temperature Regulation: The skin plays a crucial role in regulating body temperature through sweat production and blood flow.
3. Immunological Function: The skin contains immune cells that help to protect the body against infection and disease.
4. Vitamin D Synthesis: The skin is able to synthesize vitamin D when exposed to sunlight.
5. Sensory Perception: The skin contains nerve endings that allow for the perception of touch, pressure, temperature, and pain.
6. Wound Healing: When the skin is injured, a complex series of physiological processes are initiated to repair the damage and restore the barrier function.
7. Excretion: The skin helps to eliminate waste products through sweat.
8. Hydration: The skin maintains hydration by regulating water loss and absorbing moisture from the environment.
9. Pigmentation: The production of melanin in the skin provides protection against UV radiation and determines skin color.
10. Growth and Differentiation: The skin constantly renews itself through a process of cell growth and differentiation, where stem cells in the basal layer divide and differentiate into mature skin cells that migrate to the surface and are eventually shed.

Dextrans are a type of complex glucose polymers that are formed by the action of certain bacteria on sucrose. They are branched polysaccharides consisting of linear chains of α-1,6 linked D-glucopyranosyl units with occasional α-1,3 branches.

Dextrans have a wide range of applications in medicine and industry. In medicine, dextrans are used as plasma substitutes, volume expanders, and anticoagulants. They are also used as carriers for drugs and diagnostic agents, and in the manufacture of immunoadsorbents for the removal of toxins and pathogens from blood.

Dextrans can be derived from various bacterial sources, but the most common commercial source is Leuconostoc mesenteroides B-512(F) or L. dextranicum. The molecular weight of dextrans can vary widely, ranging from a few thousand to several million Daltons, depending on the method of preparation and purification.

Dextrans are generally biocompatible and non-toxic, but they can cause allergic reactions in some individuals. Therefore, their use as medical products requires careful monitoring and testing for safety and efficacy.

Polymethacrylic acids are not typically referred to as a medical term, but rather as a chemical one. They are a type of synthetic polymer made up of repeating units of methacrylic acid (MAA). These polymers have various applications in different industries, including the medical field.

In medicine, polymethacrylates are often used in the formulation of controlled-release drug delivery systems, such as beads or microspheres, due to their ability to swell and shrink in response to changes in pH or temperature. This property allows for the gradual release of drugs encapsulated within these polymers over an extended period.

Polymethacrylates are also used in dental applications, such as in the production of artificial teeth and dentures, due to their durability and resistance to wear. Additionally, they can be found in some surgical sealants and adhesives.

While polymethacrylic acids themselves may not have a specific medical definition, their various forms and applications in medical devices and drug delivery systems contribute significantly to the field of medicine.

Tissue culture techniques refer to the methods used to maintain and grow cells, tissues or organs from multicellular organisms in an artificial environment outside of the living body, called an in vitro culture. These techniques are widely used in various fields such as biology, medicine, and agriculture for research, diagnostics, and therapeutic purposes.

The basic components of tissue culture include a sterile growth medium that contains nutrients, growth factors, and other essential components to support the growth of cells or tissues. The growth medium is often supplemented with antibiotics to prevent contamination by microorganisms. The cells or tissues are cultured in specialized containers called culture vessels, which can be plates, flasks, or dishes, depending on the type and scale of the culture.

There are several types of tissue culture techniques, including:

1. Monolayer Culture: In this technique, cells are grown as a single layer on a flat surface, allowing for easy observation and manipulation of individual cells.
2. Organoid Culture: This method involves growing three-dimensional structures that resemble the organization and function of an organ in vivo.
3. Co-culture: In co-culture, two or more cell types are grown together to study their interactions and communication.
4. Explant Culture: In this technique, small pieces of tissue are cultured to maintain the original structure and organization of the cells within the tissue.
5. Primary Culture: This refers to the initial culture of cells directly isolated from a living organism. These cells can be further subcultured to generate immortalized cell lines.

Tissue culture techniques have numerous applications, such as studying cell behavior, drug development and testing, gene therapy, tissue engineering, and regenerative medicine.

... physical hydrogels and chemical hydrogels. Chemical hydrogels have covalent cross-linking bonds, whereas physical hydrogels ... Hydrogels generated in this manner are sometimes called 'permanent' hydrogels. Hydrogels are prepared using a variety of ... The term 'hydrogel' was coined in 1894. The crosslinks which bond the polymers of a hydrogel fall under two general categories ... Gelatin hydrogels are formed by temperature change. A water solution of gelatin forms an hydrogel at temperatures below 37-35 ° ...
Impregnated hydrogel dressings are dry dressings (e.g. gauzes) saturated with an amorphous hydrogel. Sprayable hydrogel ... "Hydrogels: Sheets". Wound Source. "Hydrogels: Amorphous". Wound Source. "Hydrogels: Impregnated". Wound Source. He, Jacqueline ... Self-assembling designer peptide hydrogels are another type of synthetic hydrogel in development. Natural hydrogel dressings ... The efficacy of hydrogel dressings has been assessed on various wound types. There is some evidence to suggest that hydrogels ...
For example, a hydrogel based on gum tragacanth increases the water content of clay soil by up to 5.35% and of sandy loam by up ... these may be mitigated with hydrogels. Hydrogels are hydrophilic crosslinked polymers that form three-dimensional molecular ... Hydrogels of different kinds could be useful in agriculture, reducing drought stress in plants, making better use of irrigation ... Hydrogels developed for this purpose include polymers of oligooxyethylene methacrylate, linked by ionic and covalent bonds to a ...
Although only being able to produce short hydrogel fibers, production of hydrogel fiber by polymerizing the hydrogel network ... Hydrogel fiber is a hydrogel made into a fibrous state, where its width is significantly smaller than its length. The ... Hydrogel fiber can be used to fabricate scaffolds for cell growth and drug release. Stimuli-responsive hydrogel fibers can be ... But the production of hydrogel fiber can be challenging as the hydrogel is crosslinked and can not be shaped into a fibrous ...
... is the hydrogel viscosity Typical Rf-PEG hydrogel diffusivities for 2 nm quantum dots are on the order of 10−16 m2/s, so ... Hydrogel encapsulation of the QDs opens up a new range of applications, such as: Biosensors Enzymes and other bio-active ... The formation of hydrogels is a phenomenon observed in superabsorbent polymers, or "slush powders," in which the polymer, often ... It has been observed that a stable hydrogel can only be formed with PEG backbones weighing between six and ten thousand Daltons ...
... are not to be confused with nanogel, a nanoparticle composed of a hydrogel. The synthesis of ... The responsiveness of hydrogels is a result of their molecular structure and polymer networks. Hydrogel nanoparticles have a ... Hydrogels are controlled drug delivery agents that can be engineered to have desired properties. Specifically, hydrogels can be ... The stimulus-sensitivity of hydrogels allow for a responsive release system where the hydrogels can be designed to deliver the ...
... are a specialized type of polymer hydrogel. A hydrogel is a macromolecular polymer gel constructed of a ... hydrogels Polyethylene glycol(PEG) polymers are synthetic materials that can be crosslinked to form hydrogels. PEG hydrogels ... Self-healing hydrogels encompass a wide range of applications. With a high biocompatibility, hydrogels are useful for a number ... A hybrid of these two polymer types allows for the creation of hydrogels with novel properties. An example of a hybrid hydrogel ...
These fibers can be used to create a hydrogel, which is a type of material that is made up of a network of cross-linked polymer ... Hydrogel from wood-based nanofibrillated cellulose (NFC) is used as a matrix for 3D cell culture, providing a three-dimensional ... NFC hydrogel in 3D cell culture offers a platform for various biomedical applications. Different cell lines and cell types have ... GrowDex is NFC hydrogel for 3D cell culture commercialized by UPM, Finland. NFC fiber network structure and dimensions in ...
Hydrogel size and type are the two main properties considered in designing hydrogels when seeking the optimal delivery route ... Since traditional hydrogels were able to encapsulate and carry materials, research into drug-loaded hydrogels began to expand ... Dubbed as "smart hydrogels" or "stimuli-responsive hydrogels", these gels are able to dynamically respond to external or ... Physical hydrogels contain reversible matrices of hydrogen and non-covalent bonds, while chemical hydrogels are composed of ...
2015). Photonic hydrogel sensors. Biotechnology advances. 34. 10.1016/j.biotechadv.2015.10.005. Ranft, Annekathrin & ... "Download citation of Photonic hydrogel sensors". ResearchGate. Retrieved 2020-05-25. "Download citation of 1D photonic defect ... "Photonic hydrogel sensors". Biotechnology Advances. Trends in In Vitro Diagnostics and Mobile Healthcare. 34 (3): 250-271. doi: ...
Chatterji, Prabha R. (5 August 1990). "Interpenetrating hydrogel networks. I. The gelatin-polyacrylamide system". Journal of ...
Van Vliet, Krystyn J. (2006). "3.032 Mechanical Behavior of Materials" Cacopardo, Ludovica (Jan 2019). "Engineering hydrogel ...
Hydrogel is a porous material that can hold a large amount of water while maintaining its shape. The application of hydrogel ... The significant reaction involved the synthesis of a hydrogel. ... "Application of Riboflavin Photochemical Properties in Hydrogel ... "Hydrogel properties and applications". Journal of Materials Chemistry B. 7 (10): 1523-1525. doi:10.1039/C9TB90023C. ISSN 2050- ...
Abad, "PVP-Carrageenan Hydrogel Dressing." 2008. De Guzman, "Radiation-Sterilized Honey Alginate Wound Dressing for Exudating ... Between 2001 and 2005, a polyvinylpyrrolidone carrageenan hydrogel dressing for burns and wounds was developed by the PNRI as ... Abad, Lucille V. "PVP-Carrageenan Hydrogel Dressing." PNRI, July 2008. Retrieved July 10, 2017. Abad, Lucille V. "Radiation ...
erratum) M. L. Oyen (5 December 2013). "Mechanical characterisation of hydrogel materials". International Materials Reviews. 59 ...
She created polymer hydrogel beads that are responsive to enzymes. She is working with the Medical Research Scotland to create ... Ulijn, Rein V.; McConnell, Gail; Thornton, Paul D. (2005). "Enzyme responsive polymer hydrogel beads". Chemical Communications ...
"Editorial - Should Silicone Hydrogels be Placed in a Separate FDA Soft Contact Lens Category?". www.siliconehydrogels.org. ... Newer soft lens materials include silicone-hydrogels to provide more oxygen to your eye while you wear your lenses. The first ... "The FDA has created the 4 Lens groups of hydrogels Materials to clarify categories of similar polymers for investigating ... There are three generations of silicone hydrogel contact lens materials: "About Contact Lenses - clma.net". clma.net. Contact ...
Jung S, Kim BK, Lee S, Yoon S, Im H, Kim SK (2018). "Multiplexed on-chip real-time PCR using hydrogel spot array for microRNA ... Hydrogel fibers provide an intriguing option for biocompatible material for drug delivery and bioprinting of materials that can ... Sun, F.; Zhang, W.-B.; Mahdavi, A.; Arnold, F. H.; Tirrell, D. A. (2014-07-21). "Synthesis of bioactive protein hydrogels by ... The synthesis of gel particles also known as hydrogels, microgels, and nanogels, has been an area of interest for researchers ...
... also aids synthesis of nanocomposite hydrogels. These gels are made of water-swellable nano-scale clay ( ... Haraguchi, K. (2008). "Nanocomposite hydrogels". Current Opinion in Solid State and Materials Science. 11 (3-4): 47-54. Bibcode ... Haraguchi, K.; Takehisa T. (2002). "Nanocomposite hydrogels: a unique organic-inorganic network structure with extraordinary ...
... continuing to offer peptide-based hydrogels amongst other biomaterials. The hydrogels can be used to improve the quality of ... The synthetic peptide hydrogels were so successful that she set up the spin-out company PeptiGelDesign, a group which worked to ... Miller was awarded a small grant from the University of Manchester to develop the synthesis of peptide-based hydrogels. ... Yan, Hui; Saiani, Alberto; Gough, Julie E.; Miller, Aline F. (1 October 2006). "Thermoreversible Protein Hydrogel as Cell ...
Stimuli-responsive gels (hydrogels, when the swelling agent is an aqueous solution) are a special kind of swellable polymer ... Richter, A.; Paschew, G.; Klatt, S.; Lienig, J.; Arndt, K.-F.; Adler, H.-J. (2008). "Review on Hydrogel-based pH Sensors and ... Gerlach, G.; Arndt, K.-F. (2009). Hydrogel Sensors and Actuators (First ed.). Berlin: Springer. ISBN 978-3-540-75644-6. Bar- ... To avoid the electrolysis of water hydrogel-based microfluidic devices are mainly based on temperature-responsive polymers with ...
... is classified as a hydrogel. Gelatin is nearly tasteless and odorless with a colorless or slightly yellow appearance. ... Biotechnology: Gelatin is also used in synthesizing hydrogels for tissue engineering applications. Gelatin is also used as a ... "Sequentially-crosslinked bioactive hydrogels as nano-patterned substrates with customizable stiffness and degradation for ...
Dumville JC, Stubbs N, Keogh SJ, Walker RM, Liu Z (February 2015). Dumville JC (ed.). "Hydrogel dressings for treating pressure ... Evidence supporting the use of alginate dressings, foam dressings, and hydrogel dressings. and the benefits of these dressings ...
He is known for creating and developing the technologies of hydrogel-tissue chemistry (e.g., CLARITY, STARmap) and optogenetics ... Viviana Gradinaru; Jennifer Treweek; Kristin Overton; Karl Deisseroth (2018). "Hydrogel-tissue chemistry: principles and ... A key feature of HTC is that the hydrogel-tissue hybrid "becomes the substrate for future chemical and optical interrogation ... "for his discoveries in optogenetics and hydrogel-tissue chemistry, as well as his research into the neural circuit basis of ...
At its simplest, a bioreactor space will be created between tissue layers through the use of hydrogel injections to create a ... Aberle T, Franke K, Rist E, Benz K, Schlosshauer B (2014). "Cell-Type Specific Four-Component Hydrogel". PLOS ONE. 9 (1): ... Zhu, Junmin (June 2010). "Bioactive modification of poly(ethylene glycol) hydrogels for tissue engineering". Biomaterials. 31 ( ... Tuning the Mechanical Properties of Chondroitin Sulfate Hydrogels by Copolymerization with Oligo (ethylene glycol) Diacrylates ...
Cochrane Wounds Group) (August 2022). "Hydrogel dressings for venous leg ulcers". The Cochrane Database of Systematic Reviews. ...
"Modular Integration of Hydrogel Neural Interfaces". ACS Central Science. 7 (9): 1516-1523. doi:10.26434/chemrxiv.14541432. PMC ... even more advanced neural interfaces that can be highly customized and include materials such as photoresists and hydrogels. ...
Due to this it is used widely in wound care products, including glycerin based hydrogel sheets for burns and other wound care. ... Stout, Edward I.; McKessor, Angie (February 2012). "Glycerin-Based Hydrogel for Infection Control". Advances in Wound Care. 1 ( ...
Li J, Li X, Ni X, Wang X, Li H, Leong KW (August 2006). "Self-assembled supramolecular hydrogels formed by biodegradable PEO- ... Lu HD, Charati MB, Kim IL, Burdick JA (March 2012). "Injectable shear-thinning hydrogels engineered with a self-assembling Dock ... Deng W, Yamaguchi H, Takashima Y, Harada A (2007-07-02). "A chemical-responsive supramolecular hydrogel from modified ... Appel EA, del Barrio J, Loh XJ, Scherman OA (September 2012). "Supramolecular polymeric hydrogels". Chemical Society Reviews. ...
Hydrogels have a high water content, with some hydrogels containing up to 90% water. Active drugs and other substances ... Hydrogels are biocompatible. They also swell to a greater volume than organogels when in contact with water and other natural ... Hydrogels can be used as drug delivery vehicles, for transdermal application, ophthalmic drug delivery, cancer treatment or for ... Examples of hydrogels include aluminum oxide gels, and bentonite magma. Drugs administered through topical application can act ...
Cosmetics Database Rating for Vitamasques Revive Hydrogel Patches. ...
Researchers have developed a hydrogel that has the potential to treat rheumatoid arthritis by absorbing the excess fluid that ... The hydrogel consists of polyacrylamide - a water-soluble acrylamide polymer - and a new cross-linking agent called NOCCL. ... Targeting nitric oxide with a hydrogel. With this in mind, Kim and colleagues sought to develop a new rheumatoid arthritis ... The result is a hydrogel that responds to nitric oxide once the transient gas has left circulation and bound to other molecules ...
... physical hydrogels and chemical hydrogels. Chemical hydrogels have covalent cross-linking bonds, whereas physical hydrogels ... Hydrogels generated in this manner are sometimes called permanent hydrogels. Hydrogels are prepared using a variety of ... The term hydrogel was coined in 1894. The crosslinks which bond the polymers of a hydrogel fall under two general categories ... Gelatin hydrogels are formed by temperature change. A water solution of gelatin forms an hydrogel at temperatures below 37-35 ° ...
... the combination of stem cells and stem cell derivatives with hydrogel is an attractive research topic in hydrogel preparation ... Among these, hydrogels are widely used as wound care materials due to their good biocompatibility, moisturizing effect, ... Advances of hydrogel combined with stem cells in promoting chronic wound healing.. ... Advances of hydrogel combined with stem cells in promoting chronic wound healing. ...
The antimicrobial hydrogel developed by IBM Research and IBN is comprised of more than 90 percent water, making it easy to ... The synthetic hydrogel is the biodegradable, biocompatible and non-toxic, and its ability to form spontaneously when heated to ... So, how these antimicrobial hydrogels work?. "We were driven to develop a more effective therapy against superbugs due to the ... Tags: biocompatible, degradable, hydrogel, IBM Research, institute of bioengineering and nanotechnology, medicine, ...
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Discover the difference that silicone hydrogel contact lenses can make for your eye health and comfort. Learn more about the ... Silicone Hydrogel: Whats the Difference? Silicone hydrogel contact lenses are named after the material used to make them. ... Benefits of Silicone Hydrogel Lenses The main benefit of silicone hydrogel lenses is that they satisfy both oxygen permeability ... Choosing a Silicone Hydrogel Different types of silicone hydrogel materials are used in the manufacture of lenses to suit ...
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Research has uncovered disparities in the clinical outcomes between Caucasian and minority patients with PNETs, particularly Black patients. Black patients with PNETs are more likely to present with metastatic disease, are less likely to undergo curative surgery, and have a 20% worse overall survival than white patients. However, Black patients who have their tumors resected have the same overall survival as white patients. Dr. Rose and his colleagues are working to determine which epigenetic mutation is driving early tumor metastasis in Black patients.. ...
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The hematuria catheters are a hydrogel coated latex catheter with nylon coils. They are available with different tip ... The hematuria catheters are a hydrogel coated latex catheter with nylon coils. They are available with different tip ... The hematuria catheters are a hydrogel coated latex catheter with nylon coils. They are available with different tip ...
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Hydrogel Systems for Gas Channeling and Leakage Control in CO2 EOR and Storage in Hydrocarbon Reservoirs Xin Wen, Yang Zhao, ... This paper reviewed the research progress and existing problems of four kinds of hydrogels and looked forward to the future ...
After allowing dry hydrogel granules to expand freely in distilled water for 24 hours, hydrogel granules expanded 317 and 372 ... Air space in pine bark + sand was reduced with all hydrogel additions. The dry weigh, of hydrogel cubes recovered from both ... Hydrogel cubes placed in direct contact with the pressure plate released ≈95% of their water at pressures ≤ 1.5 MPa. ... Conversely, recovered hydrogel cubes from substrates watered to drainage (-10% excess) for 6 weeks absorbed 25 to 55 times ...
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Drug-loaded low methoxy pectin solution was added to calcium chloride solution to form hydrogels. The drug-loaded pectin-based ... hydrogels were dehydrated in acetonitrile-water and subsequently dried using either supercritical carbon dioxide (scCO2) or ...
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  • 8,9 3D printing of nanocellulose hydrogels is being used in biomedical applications to support living cell growth for tissue engineering, implants, and cardiovascular devices. (cdc.gov)
  • Alginate hydrogels are formed by ionic interactions between alginate and double-charged cations. (wikipedia.org)
  • Responsive Hydrogel Colloids: Structure, Interactions, Phase Behaviour and Equilibrium and Non-equilibrium Transitions of Microgel Dispersions. (lu.se)
  • In hydrogels the porous permeable solid is a water insoluble three dimensional network of natural or synthetic polymers and a fluid, having absorbed a large amount of water or biological fluids. (wikipedia.org)
  • The crosslinks which bond the polymers of a hydrogel fall under two general categories: physical hydrogels and chemical hydrogels. (wikipedia.org)
  • Hydrogels are prepared using a variety of polymeric materials, which can be divided broadly into two categories according to their origin: natural or synthetic polymers. (wikipedia.org)
  • Analogous to how zipper teeth link together, the short segments on the new polymers also interlock, thickening the water-based solution into re-moldable and compliant hydrogels. (robaid.com)
  • The therapies, developed in collaboration with the University of Animal and Fishery Sciences, Kolkata, include three hydrogel formulations that are blends of silk fibroin and other polymers. (enewstime.in)
  • Advances of hydrogel combined with stem cells in promoting chronic wound healing. (iasp-pain.org)
  • In this, the solution is frozen for a few hours, then thawed at room temperature, and the cycle is repeated until a strong and stable hydrogel is formed. (wikipedia.org)
  • The team paired those hydrogel systems, stable from about 39 degrees to 104 degrees Fahrenheit, with the antibiotic ciprofloxacin, which itself doesn't require refrigeration. (fiercepharma.com)
  • citation needed] Chemical hydrogels can result in strong reversible or irreversible gels due to the covalent bonding. (wikipedia.org)
  • Researchers from IBM and the Institute of Bioengineering and Nanotechnology (IBN), Singapore, revealed an antimicrobial hydrogel that can break through diseased biofilms and deal with drug-resistant bacteria upon contact. (robaid.com)
  • When compared to capabilities of modern-day antibiotics and hydrogels, this new technology carries immense potential", said James Hedrick, Advanced Organic Materials Scientist, IBM Research, "This new technology is appearing at a crucial time as traditional chemical and biological techniques for dealing with drug-resistant bacteria and infectious diseases are increasingly problematic. (robaid.com)
  • However, unlike most antibiotics and hydrogels, which target the internal machinery of bacteria to prevent replication, this hydrogel destroys the bacteria by membrane disruption. (robaid.com)
  • In cell cultures, the drug-infused hydrogels managed to wipe out the bacteria Pseudomonas aeruginosa and Staphylococcus aureus-the two major culprits behind swimmer's ear-at doses 100 times lower than those used in most ear drops, the team said. (fiercepharma.com)
  • Many hydrogels are synthetic, but some are derived from nature. (wikipedia.org)
  • Whereas natural hydrogels are usually non-toxic, and often provides other advantages for medical use, such as biocompatibility, biodegradability, antibiotic/antifungal effect and improve regeneration of nearby tissue, their stability and strength is usually much lower than synthetic hydrogels. (wikipedia.org)
  • There are also synthetic hydrogels than can be used for medical applications, such as polyethylene glycol (PEG), polyacrylate, and polyvinylpyrrolidone (PVP). (wikipedia.org)
  • The synthetic hydrogel is the biodegradable, biocompatible and non-toxic, and its ability to form spontaneously when heated to body temperature makes it ideal for combat against health hazards. (robaid.com)
  • Description: The PETITFEE Artichoke Soothing Hydrogel Eye Mask are hydrogel eye patches formulated with Artichoke extract providing an instant cooling effect and soothing irritated skin. (koreanskincare.be)
  • Among these, hydrogels are widely used as wound care materials due to their good biocompatibility, moisturizing effect, adhesion, and ductility. (iasp-pain.org)
  • These bioinks are shear thinning, resist cell sedimentation, improve viability of multiple cell types, and enhance mechanical stability in hydrogels derived from them. (lu.se)
  • The team recently reported the details of their novel hydrogel in the journal Advanced Materials . (medicalnewstoday.com)
  • researchers have now created a hydrogel that could absorb the excess joint fluid that arises with disease, as well as deliver medications to affected joints. (medicalnewstoday.com)
  • The researchers now plan to test a nano-sized form of the hydrogel in mouse models of rheumatoid arthritis. (medicalnewstoday.com)
  • Out of the three formulations, one is an injectable hydrogel, which can be injected in a minimally invasive manner directly into the meniscus site to expedite the healing of smaller injuries, the researchers said. (enewstime.in)
  • Silicone hydrogels generally improve comfort and allow for longer wear, so check with a professional to make sure the lenses are right for you. (lurube.com)
  • Physical separation of healthy tissue and target volumes in prostate radiotherapy through the insertion of hydrogel can improve patient toxicity rates. (bvsalud.org)
  • Most oligopeptide hydrogels have a β-sheet structure, and assemble to form fibers, although α-helical peptides have also been reported. (wikipedia.org)
  • Drug-loaded low methoxy pectin solution was added to calcium chloride solution to form hydrogels. (ssrn.com)
  • In this method, photoinitiators, compounds that cleave from the absorption of photons, are added to the precursor solution which will become the hydrogel. (wikipedia.org)
  • Silicone hydrogel contact lenses are named after the material used to make them. (lurube.com)
  • Silicone hydrogels are the most recently developed material and are aimed at increasing oxygen transmission rate (increased comfort, longer wear and benefit eye health), wettability (improved comfort), and clinical performance of lenses. (lurube.com)
  • The plan was calculated with the hydrogel segmented and material assignment set to water , and the resultant dose compared to corresponding measurement doses. (bvsalud.org)
  • More importantly, the combination of stem cells and stem cell derivatives with hydrogel is an attractive research topic in hydrogel preparation that offers great potential in chronic wound treatment. (iasp-pain.org)
  • The antimicrobial hydrogel developed by IBM Research and IBN is comprised of more than 90 percent water, making it easy to handle and apply to surfaces. (robaid.com)
  • This paper reviewed the research progress and existing problems of four kinds of hydrogels and looked forward to the future development of the CO2 consistency control gel systems. (energy-proceedings.org)
  • The properties of a hydrogel are highly dependent on the type and quantity of its crosslinks, making photopolymerization a popular choice for fine-tuning hydrogels. (wikipedia.org)
  • Decrease quantity for Kendall Hydrogel Dressing, ½ oz. (katymedsolutions.com)
  • Led by Monica Serban, Ph.D., the team developed two separate hydrogel delivery systems and tested them in a cell and mouse study published in the journal ACS Biomaterials Science & Engineering. (fiercepharma.com)
  • This review will illustrate the development and application of advanced stem cell therapy-based hydrogels in chronic wound healing, especially in diabetic wounds and burns. (iasp-pain.org)
  • Chemical hydrogels that contain reversible covalent cross-linking bonds such as hydrogels of thiomers being cross-linked via disulfide bonds are non-toxic and are used in numerous medicinal products. (wikipedia.org)
  • The result is a hydrogel that responds to nitric oxide once the transient gas has left circulation and bound to other molecules. (medicalnewstoday.com)
  • The hydrogel consists of polyacrylamide - a water-soluble acrylamide polymer - and a new cross-linking agent called NOCCL. (medicalnewstoday.com)
  • The main benefit of silicone hydrogel lenses is that they satisfy both oxygen permeability and water content. (lurube.com)
  • The drug-loaded pectin-based hydrogels were dehydrated in acetonitrile-water and subsequently dried using either supercritical carbon dioxide (scCO2) or freeze-drying. (ssrn.com)
  • Radiological evaluation of an iodised hydrogel for prostate radiotherapy applications. (bvsalud.org)
  • Let's take a look at what silicone hydrogels are and how they can make a difference. (lurube.com)
  • There are several generations and varieties of silicone hydrogels used to make contact lenses today. (lurube.com)
  • When Glamour Base er en ansigtsmaske som anvendes før påføring af make-up for at gøre den mere holdbar. (ellos.dk)
  • Hydrogels generated in this manner are sometimes called 'permanent' hydrogels. (wikipedia.org)