Tissue Engineering: 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.Tissue Scaffolds: 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.Biocompatible Materials: Synthetic or natural materials, other than DRUGS, that are used to replace or repair any body TISSUES or bodily function.Protein Engineering: Procedures by which protein structure and function are changed or created in vitro by altering existing or synthesizing new structural genes that direct the synthesis of proteins with sought-after properties. Such procedures may include the design of MOLECULAR MODELS of proteins using COMPUTER GRAPHICS or other molecular modeling techniques; site-specific mutagenesis (MUTAGENESIS, SITE-SPECIFIC) of existing genes; and DIRECTED MOLECULAR EVOLUTION techniques to create new genes.Biomedical Engineering: Application of principles and practices of engineering science to biomedical research and health care.Genetic Engineering: Directed modification of the gene complement of a living organism by such techniques as altering the DNA, substituting genetic material by means of a virus, transplanting whole nuclei, transplanting cell hybrids, etc.Hydrogels: 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)Porosity: 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.Bioartificial Organs: Artificial organs that are composites of biomaterials and cells. The biomaterial can act as a membrane (container) as in BIOARTIFICIAL LIVER or a scaffold as in bioartificial skin.Materials Testing: 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.Regenerative Medicine: A field of medicine concerned with developing and using strategies aimed at repair or replacement of damaged, diseased, or metabolically deficient organs, tissues, and cells via TISSUE ENGINEERING; CELL TRANSPLANTATION; and ARTIFICIAL ORGANS and BIOARTIFICIAL ORGANS and tissues.Polyesters: 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.Nanofibers: 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.Guided Tissue Regeneration: Procedures for enhancing and directing tissue repair and renewal processes, such as BONE REGENERATION; NERVE REGENERATION; etc. They involve surgically implanting growth conducive tracks or conduits (TISSUE SCAFFOLDING) at the damaged site to stimulate and control the location of cell repopulation. The tracks or conduits are made from synthetic and/or natural materials and may include support cells and induction factors for CELL GROWTH PROCESSES; or CELL MIGRATION.Bone Regeneration: Renewal or repair of lost bone tissue. It excludes BONY CALLUS formed after BONE FRACTURES but not yet replaced by hard bone.Biomimetic Materials: Materials fabricated by BIOMIMETICS techniques, i.e., based on natural processes found in biological systems.Hydrogel: A network of cross-linked hydrophilic macromolecules used in biomedical applications.Metabolic Engineering: Methods and techniques used to genetically modify cells' biosynthetic product output and develop conditions for growing the cells as BIOREACTORS.Bioreactors: Tools or devices for generating products using the synthetic or chemical conversion capacity of a biological system. They can be classical fermentors, cell culture perfusion systems, or enzyme bioreactors. For production of proteins or enzymes, recombinant microorganisms such as bacteria, mammalian cells, or insect or plant cells are usually chosen.Polymers: Compounds formed by the joining of smaller, usually repeating, units linked by covalent bonds. These compounds often form large macromolecules (e.g., BIOPOLYMERS; PLASTICS).Decanoates: Salts and esters of the 10-carbon monocarboxylic acid-decanoic acid.Absorbable 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.Mesenchymal Stromal Cells: 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.Cell Culture Techniques: Methods for maintaining or growing CELLS in vitro.Bioengineering: The application of engineering principles and methods to living organisms or biological systems.Polyglycolic Acid: A biocompatible polymer used as a surgical suture material.Osteogenesis: The process of bone formation. Histogenesis of bone including ossification.Microscopy, Electron, Scanning: 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.Silk: A continuous protein fiber consisting primarily of FIBROINS. It is synthesized by a variety of INSECTS and ARACHNIDS.Elastomers: A generic term for all substances having the properties of stretching under tension, high tensile strength, retracting rapidly, and recovering their original dimensions fully. They are generally POLYMERS.Chitosan: Deacetylated CHITIN, a linear polysaccharide of deacetylated beta-1,4-D-glucosamine. It is used in HYDROGEL and to treat WOUNDS.Microtechnology: Manufacturing technology for making microscopic devices in the micrometer range (typically 1-100 micrometers), such as integrated circuits or MEMS. The process usually involves replication and parallel fabrication of hundreds or millions of identical structures using various thin film deposition techniques and carried out in environmentally-controlled clean rooms.Compressive Strength: The maximum compression a material can withstand without failure. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed, p427)Regeneration: The physiological renewal, repair, or replacement of tissue.Extracellular Matrix: A meshwork-like substance found within the extracellular space and in association with the basement membrane of the cell surface. It promotes cellular proliferation and provides a supporting structure to which cells or cell lysates in culture dishes adhere.Chondrogenesis: The formation of cartilage. This process is directed by CHONDROCYTES which continually divide and lay down matrix during development. It is sometimes a precursor to OSTEOGENESIS.Mechanical Phenomena: The properties and processes of materials that affect their behavior under force.Nanostructures: Materials which have structured components with at least one dimension in the range of 1 to 100 nanometers. These include NANOCOMPOSITES; NANOPARTICLES; NANOTUBES; and NANOWIRES.Implants, Experimental: Artificial substitutes for body parts and materials inserted into organisms during experimental studies.Cartilage: A non-vascular form of connective tissue composed of CHONDROCYTES embedded in a matrix that includes CHONDROITIN SULFATE and various types of FIBRILLAR COLLAGEN. There are three major types: HYALINE CARTILAGE; FIBROCARTILAGE; and ELASTIC CARTILAGE.Biomimetics: An interdisciplinary field in materials science, ENGINEERING, and BIOLOGY, studying the use of biological principles for synthesis or fabrication of BIOMIMETIC MATERIALS.Calcium Phosphates: Calcium salts of phosphoric acid. These compounds are frequently used as calcium supplements.Hexuronic Acids: 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.Chondrocytes: Polymorphic cells that form cartilage.Tensile Strength: The maximum stress a material subjected to a stretching load can withstand without tearing. (McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed, p2001)Glucuronic Acid: 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.Alginates: Salts of alginic acid that are extracted from marine kelp and used to make dental impressions and as absorbent material for surgical dressings.Bone Substitutes: Synthetic or natural materials for the replacement of bones or bone tissue. They include hard tissue replacement polymers, natural coral, hydroxyapatite, beta-tricalcium phosphate, and various other biomaterials. The bone substitutes as inert materials can be incorporated into surrounding tissue or gradually replaced by original tissue.Bone and Bones: A specialized CONNECTIVE TISSUE that is the main constituent of the SKELETON. The principle cellular component of bone is comprised of OSTEOBLASTS; OSTEOCYTES; and OSTEOCLASTS, while FIBRILLAR COLLAGENS and hydroxyapatite crystals form the BONE MATRIX.Cell Differentiation: Progressive restriction of the developmental potential and increasing specialization of function that leads to the formation of specialized cells, tissues, and organs.Gelatin: 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.Stem Cells: Relatively undifferentiated cells that retain the ability to divide and proliferate throughout postnatal life to provide progenitor cells that can differentiate into specialized cells.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Surface Properties: Characteristics or attributes of the outer boundaries of objects, including molecules.Fibroins: Fibrous proteins secreted by INSECTS and SPIDERS. Generally, the term refers to silkworm fibroin secreted by the silk gland cells of SILKWORMS, Bombyx mori. Spider fibroins are called spidroins or dragline silk fibroins.Durapatite: The mineral component of bones and teeth; it has been used therapeutically as a prosthetic aid and in the prevention and treatment of osteoporosis.Dental Pulp: A richly vascularized and innervated connective tissue of mesodermal origin, contained in the central cavity of a tooth and delimited by the dentin, and having formative, nutritive, sensory, and protective functions. (Jablonski, Dictionary of Dentistry, 1992)Nanocomposites: Nanometer-scale composite structures composed of organic molecules intimately incorporated with inorganic molecules. (Glossary of Biotechnology and Nanobiotechology Terms, 4th ed)Lactic Acid: A normal intermediate in the fermentation (oxidation, metabolism) of sugar. The concentrated form is used internally to prevent gastrointestinal fermentation. (From Stedman, 26th ed)Cell Engineering: Methods and techniques used to modify or select cells and develop conditions for growing cells for biosynthetic production of molecules (METABOLIC ENGINEERING), for generation of tissue structures and organs in vitro (TISSUE ENGINEERING), or for other BIOENGINEERING research objectives.Cell Proliferation: All of the processes involved in increasing CELL NUMBER including CELL DIVISION.Elastic Modulus: 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.Collagen: A polypeptide substance comprising about one third of the total protein in mammalian organisms. It is the main constituent of SKIN; CONNECTIVE TISSUE; and the organic substance of bones (BONE AND BONES) and teeth (TOOTH).Polyurethanes: A group of thermoplastic or thermosetting polymers containing polyisocyanate. They are used as ELASTOMERS, as coatings, as fibers and as foams.Skin, Artificial: Synthetic material used for the treatment of burns and other conditions involving large-scale loss of skin. It often consists of an outer (epidermal) layer of silicone and an inner (dermal) layer of collagen and chondroitin 6-sulfate. The dermal layer elicits new growth and vascular invasion and the outer layer is later removed and replaced by a graft.Gels: Colloids with a solid continuous phase and liquid as the dispersed phase; gels may be unstable when, due to temperature or other cause, the solid phase liquefies; the resulting colloid is called a sol.Cell Shape: The quality of surface form or outline of CELLS.Periodontal Ligament: The fibrous CONNECTIVE TISSUE surrounding the TOOTH ROOT, separating it from and attaching it to the alveolar bone (ALVEOLAR PROCESS).Nanotechnology: The development and use of techniques to study physical phenomena and construct structures in the nanoscale size range or smaller.Bone Morphogenetic Protein 2: A potent osteoinductive protein that plays a critical role in the differentiation of osteoprogenitor cells into OSTEOBLASTS.Biomechanical Phenomena: The properties, processes, and behavior of biological systems under the action of mechanical forces.Osteoblasts: Bone-forming cells which secrete an EXTRACELLULAR MATRIX. HYDROXYAPATITE crystals are then deposited into the matrix to form bone.Stress, Mechanical: A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area.Fibrocartilage: A type of CARTILAGE whose matrix contains large bundles of COLLAGEN TYPE I. Fibrocartilage is typically found in the INTERVERTEBRAL DISK; PUBIC SYMPHYSIS; TIBIAL MENISCI; and articular disks in synovial JOINTS. (From Ross et. al., Histology, 3rd ed., p132,136)Ceramics: Products made by baking or firing nonmetallic minerals (clay and similar materials). In making dental restorations or parts of restorations the material is fused porcelain. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed & Boucher's Clinical Dental Terminology, 4th ed)Adult Stem Cells: Cells with high proliferative and self renewal capacities derived from adults.Cell Survival: 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.Cell Adhesion: Adherence of cells to surfaces or to other cells.Drug Delivery Systems: 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.Chemical EngineeringGlycosaminoglycans: Heteropolysaccharides which contain an N-acetylated hexosamine in a characteristic repeating disaccharide unit. The repeating structure of each disaccharide involves alternate 1,4- and 1,3-linkages consisting of either N-acetylglucosamine or N-acetylgalactosamine.Heart Valves: Flaps of tissue that prevent regurgitation of BLOOD from the HEART VENTRICLES to the HEART ATRIA or from the PULMONARY ARTERIES or AORTA to the ventricles.Cartilage, Articular: A protective layer of firm, flexible cartilage over the articulating ends of bones. It provides a smooth surface for joint movement, protecting the ends of long bones from wear at points of contact.Dermatologic Surgical Procedures: Operative procedures performed on the SKIN.Biotechnology: Body of knowledge related to the use of organisms, cells or cell-derived constituents for the purpose of developing products which are technically, scientifically and clinically useful. Alteration of biologic function at the molecular level (i.e., GENETIC ENGINEERING) is a central focus; laboratory methods used include TRANSFECTION and CLONING technologies, sequence and structure analysis algorithms, computer databases, and gene and protein structure function analysis and prediction.Alkaline Phosphatase: An enzyme that catalyzes the conversion of an orthophosphoric monoester and water to an alcohol and orthophosphate. EC 18.104.22.168.Cell Transplantation: Transference of cells within an individual, between individuals of the same species, or between individuals of different species.Tissue Culture Techniques: 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.Polyethylene Glycols: 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.Stem Cell Transplantation: The transfer of STEM CELLS from one individual to another within the same species (TRANSPLANTATION, HOMOLOGOUS) or between species (XENOTRANSPLANTATION), or transfer within the same individual (TRANSPLANTATION, AUTOLOGOUS). The source and location of the stem cells determines their potency or pluripotency to differentiate into various cell types.Blood Vessels: Any of the tubular vessels conveying the blood (arteries, arterioles, capillaries, venules, and veins).Polyglactin 910: A polyester used for absorbable sutures & surgical mesh, especially in ophthalmic surgery. 2-Hydroxy-propanoic acid polymer with polymerized hydroxyacetic acid, which forms 3,6-dimethyl-1,4-dioxane-dione polymer with 1,4-dioxane-2,5-dione copolymer of molecular weight about 80,000 daltons.Nanomedicine: The branch of medicine concerned with the application of NANOTECHNOLOGY to the prevention and treatment of disease. It involves the monitoring, repair, construction, and control of human biological systems at the molecular level, using engineered nanodevices and NANOSTRUCTURES. (From Freitas Jr., Nanomedicine, vol 1, 1999).Hyaline Cartilage: A type of CARTILAGE characterized by a homogenous amorphous matrix containing predominately TYPE II COLLAGEN and ground substance. Hyaline cartilage is found in ARTICULAR CARTILAGE; COSTAL CARTILAGE; LARYNGEAL CARTILAGES; and the NASAL SEPTUM.Cells, Immobilized: 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)Umbilical Cord: The flexible rope-like structure that connects a developing FETUS to the PLACENTA in mammals. The cord contains blood vessels which carry oxygen and nutrients from the mother to the fetus and waste products away from the fetus.Blood Vessel Prosthesis: Device constructed of either synthetic or biological material that is used for the repair of injured or diseased blood vessels.Mesenchymal Stem Cell Transplantation: Transfer of MESENCHYMAL STEM CELLS between individuals within the same species (TRANSPLANTATION, HOMOLOGOUS) or transfer within the same individual (TRANSPLANTATION, AUTOLOGOUS).Bioprosthesis: Prosthesis, usually heart valve, composed of biological material and whose durability depends upon the stability of the material after pretreatment, rather than regeneration by host cell ingrowth. Durability is achieved 1, mechanically by the interposition of a cloth, usually polytetrafluoroethylene, between the host and the graft, and 2, chemically by stabilization of the tissue by intermolecular linking, usually with glutaraldehyde, after removal of antigenic components, or the use of reconstituted and restructured biopolymers.Dental Papilla: Mesodermal tissue enclosed in the invaginated portion of the epithelial enamel organ and giving rise to the dentin and pulp.Microspheres: Small uniformly-sized spherical particles, of micrometer dimensions, frequently labeled with radioisotopes or various reagents acting as tags or markers.Periodontium: The structures surrounding and supporting the tooth. Periodontium includes the gum (GINGIVA), the alveolar bone (ALVEOLAR PROCESS), the DENTAL CEMENTUM, and the PERIODONTAL LIGAMENT.Collagen Type II: A fibrillar collagen found predominantly in CARTILAGE and vitreous humor. It consists of three identical alpha1(II) chains.Fibrin: A protein derived from FIBRINOGEN in the presence of THROMBIN, which forms part of the blood clot.Menisci, Tibial: The interarticular fibrocartilages of the superior surface of the tibia.Tendons: Fibrous bands or cords of CONNECTIVE TISSUE at the ends of SKELETAL MUSCLE FIBERS that serve to attach the MUSCLES to bones and other structures.Guided Tissue Regeneration, Periodontal: Techniques for enhancing and directing cell growth to repopulate specific parts of the PERIODONTIUM that have been damaged by PERIODONTAL DISEASES; TOOTH DISEASES; or TRAUMA, or to correct TOOTH ABNORMALITIES. Repopulation and repair is achieved by guiding the progenitor cells to reproduce in the desired location by blocking contact with surrounding tissue by use of membranes composed of synthetic or natural material that may include growth inducing factors as well.Calcification, Physiologic: Process by which organic tissue becomes hardened by the physiologic deposit of calcium salts.Periosteum: Thin outer membrane that surrounds a bone. It contains CONNECTIVE TISSUE, CAPILLARIES, nerves, and a number of cell types.Equipment Design: Methods of creating machines and devices.Wound Healing: Restoration of integrity to traumatized tissue.Neovascularization, Physiologic: The development of new BLOOD VESSELS during the restoration of BLOOD CIRCULATION during the healing process.Ear Cartilage: Cartilage of the EAR AURICLE and the EXTERNAL EAR CANAL.Prostheses and Implants: Artificial substitutes for body parts, and materials inserted into tissue for functional, cosmetic, or therapeutic purposes. Prostheses can be functional, as in the case of artificial arms and legs, or cosmetic, as in the case of an artificial eye. Implants, all surgically inserted or grafted into the body, tend to be used therapeutically. IMPLANTS, EXPERIMENTAL is available for those used experimentally.Nanoparticles: Nanometer-sized particles that are nanoscale in three dimensions. They include nanocrystaline materials; NANOCAPSULES; METAL NANOPARTICLES; DENDRIMERS, and QUANTUM DOTS. The uses of nanoparticles include DRUG DELIVERY SYSTEMS and cancer targeting and imaging.Dental Cementum: The bonelike rigid connective tissue covering the root of a tooth from the cementoenamel junction to the apex and lining the apex of the root canal, also assisting in tooth support by serving as attachment structures for the periodontal ligament. (Jablonski, Dictionary of Dentistry, 1992)Dimethylpolysiloxanes: Silicone polymers which consist of silicon atoms substituted with methyl groups and linked by oxygen atoms. They comprise a series of biocompatible materials used as liquids, gels or solids; as film for artificial membranes, gels for implants, and liquids for drug vehicles; and as antifoaming agents.Apatites: A group of phosphate minerals that includes ten mineral species and has the general formula X5(YO4)3Z, where X is usually calcium or lead, Y is phosphorus or arsenic, and Z is chlorine, fluorine, or OH-. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Hyaluronic Acid: 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.Musculoskeletal System: The MUSCLES, bones (BONE AND BONES), and CARTILAGE of the body.Embryonic Stem Cells: Cells derived from the BLASTOCYST INNER CELL MASS which forms before implantation in the uterine wall. They retain the ability to divide, proliferate and provide progenitor cells that can differentiate into specialized cells.X-Ray Microtomography: X-RAY COMPUTERIZED TOMOGRAPHY with resolution in the micrometer range.Computer-Aided Design: The use of computers for designing and/or manufacturing of anything, including drugs, surgical procedures, orthotics, and prosthetics.Polypropylenes: Propylene or propene polymers. Thermoplastics that can be extruded into fibers, films or solid forms. They are used as a copolymer in plastics, especially polyethylene. The fibers are used for fabrics, filters and surgical sutures.Collagen Type I: The most common form of fibrillar collagen. It is a major constituent of bone (BONE AND BONES) and SKIN and consists of a heterotrimer of two alpha1(I) and one alpha2(I) chains.Endothelial Cells: Highly specialized EPITHELIAL CELLS that line the HEART; BLOOD VESSELS; and lymph vessels, forming the ENDOTHELIUM. They are polygonal in shape and joined together by TIGHT JUNCTIONS. The tight junctions allow for variable permeability to specific macromolecules that are transported across the endothelial layer.Cell- and Tissue-Based Therapy: Therapies that involve the TRANSPLANTATION of CELLS or TISSUES developed for the purpose of restoring the function of diseased or dysfunctional cells or tissues.Spectroscopy, Fourier Transform Infrared: A spectroscopic technique in which a range of wavelengths is presented simultaneously with an interferometer and the spectrum is mathematically derived from the pattern thus obtained.Cattle: Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.Intervertebral Disc: Any of the 23 plates of fibrocartilage found between the bodies of adjacent VERTEBRAE.Iridoids: A type of MONOTERPENES, derived from geraniol. They have the general form of cyclopentanopyran, but in some cases, one of the rings is broken as in the case of secoiridoid. They are different from the similarly named iridals (TRITERPENES).Subcutaneous Tissue: Loose connective tissue lying under the DERMIS, which binds SKIN loosely to subjacent tissues. It may contain a pad of ADIPOCYTES, which vary in number according to the area of the body and vary in size according to the nutritional state.Cryogels: Macroporous hydrogels that are produced at subzero temperatures. Cryogels have pores that are produced by growing ice crystals and have been developed with a tissue-like elasticity that is suitable for cell immunization experiments.Models, Biological: Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.Elasticity: Resistance and recovery from distortion of shape.Mechanical Processes: The behaviors of materials under force.Transforming Growth Factor beta3: A TGF-beta subtype that plays role in regulating epithelial-mesenchymal interaction during embryonic development. It is synthesized as a precursor molecule that is cleaved to form mature TGF-beta3 and TGF-beta3 latency-associated peptide. The association of the cleavage products results in the formation a latent protein which must be activated to bind its receptor.Cell Physiological Processes: Cellular functions, mechanisms, and activities.Cross-Linking Reagents: 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.SepharoseSynthetic Biology: A field of biological research combining engineering in the formulation, design, and building (synthesis) of novel biological structures, functions, and systems.Skull: The SKELETON of the HEAD including the FACIAL BONES and the bones enclosing the BRAIN.Rheology: 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.NIH 3T3 Cells: A continuous cell line of high contact-inhibition established from NIH Swiss mouse embryo cultures. The cells are useful for DNA transfection and transformation studies. (From ATCC [Internet]. Virginia: American Type Culture Collection; c2002 [cited 2002 Sept 26]. Available from http://www.atcc.org/)Dentistry: The profession concerned with the teeth, oral cavity, and associated structures, and the diagnosis and treatment of their diseases including prevention and the restoration of defective and missing tissue.Adipose Tissue: Specialized connective tissue composed of fat cells (ADIPOCYTES). It is the site of stored FATS, usually in the form of TRIGLYCERIDES. In mammals, there are two types of adipose tissue, the WHITE FAT and the BROWN FAT. Their relative distributions vary in different species with most adipose tissue being white.Equipment Failure Analysis: The evaluation of incidents involving the loss of function of a device. These evaluations are used for a variety of purposes such as to determine the failure rates, the causes of failures, costs of failures, and the reliability and maintainability of devices.Surgery, Plastic: The branch of surgery concerned with restoration, reconstruction, or improvement of defective, damaged, or missing structures.Polyhydroxyethyl Methacrylate: 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.Adipogenesis: The differentiation of pre-adipocytes into mature ADIPOCYTES.Translational Medical Research: The application of discoveries generated by laboratory research and preclinical studies to the development of clinical trials and studies in humans. A second area of translational research concerns enhancing the adoption of best practices.Aggrecans: Large HYALURONAN-containing proteoglycans found in articular cartilage (CARTILAGE, ARTICULAR). They form into aggregates that provide tissues with the capacity to resist high compressive and tensile forces.Electrochemical Techniques: The utilization of an electrical current to measure, analyze, or alter chemicals or chemical reactions in solution, cells, or tissues.Temporomandibular Joint: An articulation between the condyle of the mandible and the articular tubercle of the temporal bone.Myocytes, Smooth Muscle: Non-striated, elongated, spindle-shaped cells found lining the digestive tract, uterus, and blood vessels. They are derived from specialized myoblasts (MYOBLASTS, SMOOTH MUSCLE).Fibrillar Collagens: A family of structurally related collagens that form the characteristic collagen fibril bundles seen in CONNECTIVE TISSUE.Fumarates: Compounds based on fumaric acid.Iridoid Glycosides: A subclass of iridoid compounds that include a glycoside moiety, usually found at the C-1 position.Acrylamides: 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.Nerve Expansion: Procedures that stimulate nerve elongation over a period of time. They are used in repairing nerve tissue.Rats, Nude: A mutant strain of Rattus norvegicus without a thymus and with depressed or absent T-cell function. This strain of rats may have a small amount of hair at times, but then lose it.Tissue Transplantation: Transference of tissue within an individual, between individuals of the same species, or between individuals of different species.Fibroblasts: Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.Nanotubes: Nanometer-sized tubes composed of various substances including carbon (CARBON NANOTUBES), boron nitride, or nickel vanadate.Intercellular Signaling Peptides and Proteins: Regulatory proteins and peptides that are signaling molecules involved in the process of PARACRINE COMMUNICATION. They are generally considered factors that are expressed by one cell and are responded to by receptors on another nearby cell. They are distinguished from HORMONES in that their actions are local rather than distal.Reconstructive Surgical Procedures: Procedures used to reconstruct, restore, or improve defective, damaged, or missing structures.Coated Materials, Biocompatible: Biocompatible materials usually used in dental and bone implants that enhance biologic fixation, thereby increasing the bond strength between the coated material and bone, and minimize possible biological effects that may result from the implant itself.Dental Sac: Dense fibrous layer formed from mesodermal tissue that surrounds the epithelial enamel organ. The cells eventually migrate to the external surface of the newly formed root dentin and give rise to the cementoblasts that deposit cementum on the developing root, fibroblasts of the developing periodontal ligament, and osteoblasts of the developing alveolar bone.Bone Marrow Cells: Cells contained in the bone marrow including fat cells (see ADIPOCYTES); STROMAL CELLS; MEGAKARYOCYTES; and the immediate precursors of most blood cells.Cell SeparationStromal Cells: Connective tissue cells of an organ found in the loose connective tissue. These are most often associated with the uterine mucosa and the ovary as well as the hematopoietic system and elsewhere.Mechanotransduction, Cellular: The process by which cells convert mechanical stimuli into a chemical response. It can occur in both cells specialized for sensing mechanical cues such as MECHANORECEPTORS, and in parenchymal cells whose primary function is not mechanosensory.Information Literacy: The ability to recognize when information is needed and to locate, evaluate, and use the needed information effectively.Freeze Drying: Method of tissue preparation in which the tissue specimen is frozen and then dehydrated at low temperature in a high vacuum. This method is also used for dehydrating pharmaceutical and food products.Human Umbilical Vein Endothelial Cells: Endothelial cells that line venous vessels of the UMBILICAL CORD.Nerve Tissue: Differentiated tissue of the central nervous system composed of NERVE CELLS, fibers, DENDRITES, and specialized supporting cells.Microfluidic Analytical Techniques: Methods utilizing the principles of MICROFLUIDICS for sample handling, reagent mixing, and separation and detection of specific components in fluids.Intervertebral Disc Degeneration: Degenerative changes in the INTERVERTEBRAL DISC due to aging or structural damage, especially to the vertebral end-plates.Tooth: One of a set of bone-like structures in the mouth used for biting and chewing.Extracellular Matrix Proteins: Macromolecular organic compounds that contain carbon, hydrogen, oxygen, nitrogen, and usually, sulfur. These macromolecules (proteins) form an intricate meshwork in which cells are embedded to construct tissues. Variations in the relative types of macromolecules and their organization determine the type of extracellular matrix, each adapted to the functional requirements of the tissue. The two main classes of macromolecules that form the extracellular matrix are: glycosaminoglycans, usually linked to proteins (proteoglycans), and fibrous proteins (e.g., COLLAGEN; ELASTIN; FIBRONECTINS; and LAMININ).Particle Size: Relating to the size of solids.Coculture Techniques: A technique of culturing mixed cell types in vitro to allow their synergistic or antagonistic interactions, such as on CELL DIFFERENTIATION or APOPTOSIS. Coculture can be of different types of cells, tissues, or organs from normal or disease states.Polypodiaceae: The fern plant family of the order Polypodiales, class Filicopsida, division Pteridophyta, subkingdom Tracheobionta.Osteopontin: A negatively-charged extracellular matrix protein that plays a role in the regulation of BONE metabolism and a variety of other biological functions. Cell signaling by osteopontin may occur through a cell adhesion sequence that recognizes INTEGRIN ALPHA-V BETA-3.Multipotent Stem Cells: Specialized stem cells that are committed to give rise to cells that have a particular function; examples are MYOBLASTS; MYELOID PROGENITOR CELLS; and skin stem cells. (Stem Cells: A Primer [Internet]. Bethesda (MD): National Institutes of Health (US); 2000 May [cited 2002 Apr 5]. Available from: http://www.nih.gov/news/stemcell/primer.htm)Osteocalcin: Vitamin K-dependent calcium-binding protein synthesized by OSTEOBLASTS and found primarily in BONES. Serum osteocalcin measurements provide a noninvasive specific marker of bone metabolism. The protein contains three residues of the amino acid gamma-carboxyglutamic acid (Gla), which, in the presence of CALCIUM, promotes binding to HYDROXYAPATITE and subsequent accumulation in BONE MATRIX.Microfluidics: The study of fluid channels and chambers of tiny dimensions of tens to hundreds of micrometers and volumes of nanoliters or picoliters. This is of interest in biological MICROCIRCULATION and used in MICROCHEMISTRY and INVESTIGATIVE TECHNIQUES.Awards and PrizesArtificial Organs: Devices intended to replace non-functioning organs. They may be temporary or permanent. Since they are intended always to function as the natural organs they are replacing, they should be differentiated from PROSTHESES AND IMPLANTS and specific types of prostheses which, though also replacements for body parts, are frequently cosmetic (EYE, ARTIFICIAL) as well as functional (ARTIFICIAL LIMBS).Methacrylates: Acrylic acids or acrylates which are substituted in the C-2 position with a methyl group.Liver, Artificial: Devices for simulating the activities of the liver. They often consist of a hybrid between both biological and artificial materials.Nanotubes, Carbon: Nanometer-sized tubes composed mainly of CARBON. Such nanotubes are used as probes for high-resolution structural and chemical imaging of biomolecules with ATOMIC FORCE MICROSCOPY.ElastinSus scrofa: A species of SWINE, in the family Suidae, comprising a number of subspecies including the domestic pig Sus scrofa domestica.Organosilicon Compounds: Organic compounds that contain silicon as an integral part of the molecule.Induced Pluripotent Stem Cells: Cells from adult organisms that have been reprogrammed into a pluripotential state similar to that of EMBRYONIC STEM CELLS.Myocytes, Cardiac: Striated muscle cells found in the heart. They are derived from cardiac myoblasts (MYOBLASTS, CARDIAC).Photochemical Processes: Chemical reactions effected by light.Bone Morphogenetic Proteins: Bone-growth regulatory factors that are members of the transforming growth factor-beta superfamily of proteins. They are synthesized as large precursor molecules which are cleaved by proteolytic enzymes. The active form can consist of a dimer of two identical proteins or a heterodimer of two related bone morphogenetic proteins.Glass: Hard, amorphous, brittle, inorganic, usually transparent, polymerous silicate of basic oxides, usually potassium or sodium. It is used in the form of hard sheets, vessels, tubing, fibers, ceramics, beads, etc.Polymerization: Chemical reaction in which monomeric components are combined to form POLYMERS (e.g., POLYMETHYLMETHACRYLATE).