Progressive aggregation of protein Tau into oligomers and fibrils correlates with cognitive decline and synaptic dysfunction, leading to neurodegeneration in vulnerable brain regions in Alzheimers disease. The unmet need of effective therapy for Alzheimers disease, combined with problematic pharmacological approaches, led the field to explore immunotherapy, first against amyloid peptides and recently against protein Tau. Here we adapted the liposome-based amyloid vaccine that proved safe and efficacious, and incorporated a synthetic phosphorylated peptide to mimic the important phospho-epitope of protein Tau at residues pS396/pS404. We demonstrate that the liposome-based vaccine elicited, rapidly and robustly, specific antisera in wild-type mice and in Tau.P301L mice. Long-term vaccination proved to be safe, because it improved the clinical condition and reduced indices of tauopathy in the brain of the Tau.P301L mice, while no signs of neuro-inflammation or other adverse neurological effects were
The incorporation of poly(ethylene glycol) (PEG)-conjugated lipids in lipid-based carriers substantially prolongs the circulation lifetime of liposomes. However, the mechanism(s) by which PEG-lipids achieve this have not been fully elucidated. It is believed that PEG-lipids mediate steric stabilization, ultimately reducing surface-surface interactions including the aggregation of liposomes and/or adsorption of plasma proteins. The purpose of the studies described here was to compare the effects of PEG-lipid incorporation in liposomes on protein binding, liposome-liposome aggregation and pharmacokinetics in mice. Cholesterol-free liposomes were chosen because of their increasing importance as liposomal delivery systems and their marked sensitivity to protein binding and aggregation. Specifically, liposomes containing various molecular weight PEG-lipids at a variety of molar proportions were analyzed for in vivo clearance, aggregation state (size exclusion chromatography, quasi-elastic light ...
Comparison of liposome-based transfection reagents hr...Transfection of mammalian cell lines is enhanced by the use oflipos...Our lab has recently been interested in the transient transfection of ...The cell line used for many of our experiments is the human adrenalcar...,Transfection,of,Green,Fluorescent,Protein,into,Human,Adrenalcarcinoma,Cells,biological,advanced biology technology,biology laboratory technology,biology device technology,latest biology technology
Quantum dots (QDs) and silica nanoparticles (SNs) are new classes of fluorescent probes that overcome the limitations encountered by organic fluorophores in bioassay and biological imaging applications. We encapsulated QDs and SNs into liposomes by the reverse-phase evaporation method. Nanoparticle-loaded liposomes were separated from unencapsulated nanoparticles by size exclusion chromatography and their characteristics were investigated. Dual-color, two-photon fluorescence correlation spectroscopy was used to measure the number of nanoparticles inside each liposome. Results indicated that nanoparticle-loaded liposomes were formed and separated from unencapsulated nanoparticles by using Sepharose gel. As expected, fluorescence self-quenching of nanoparticles inside liposomes was not observed. When a 0.8 mM solution of 50 nm QDs was used for liposome preparation, each liposome encapsulated an average of three QDs. However, we could not measure the number of SNs inside each liposome due to the spectral
A promising strategy to improve the immunogenic potential of DNA vaccines is the formulation of plasmid DNA (pDNA) with cationic liposomes. In this respect, particle size may be of crucial importance. This study aimed at the evaluation of high-pressure extrusion as a method for sizing cationic liposomes after entrapment of pDNA. This is a well-known sizing method for liposomes, but so far, it has not been applied for liposomes that are already loaded with pDNA. Liposomes composed of egg PC, DOTAP, and DOPE with entrapped pDNA were prepared by the dehydration-rehydration method and subjected to various extrusion cycles, comparing different membrane pore sizes and extrusion frequencies. At optimized extrusion conditions, liposome diameter (Zave) and polydispersity index (PDI) were reduced from 560 nm and 0.56 to 150 nm and 0.14 respectively, and 35% of the pDNA was retained. Importantly, gel electrophoresis and transfection experiments with pDNA extracted from these extruded liposomes demonstrated ...
TY - JOUR. T1 - Liposomal drug delivery system. AU - Maruyama, Kazuo. AU - Kennel, Stephen. AU - Huang, Leaf. PY - 1990/8/1. Y1 - 1990/8/1. N2 - We have recently described an immunoliposome targeting system which involves the use of monoclonal antibodies specific for the pulmonary endothelial cells. We have employed the antibodies, 34A and 201B, which bind to a surface glycoprotein, gp112, which is specifically expressed in high concentrations in the capillary endothelial cells of the mouse lung. Intravenously injected immunoliposomes (34A- or 201B-liposomes) to the mice gain direct access and bind efficiently to the lung. Approximately 50% of the injected dose was accumulated in the lung for 34A-liposomes which contained an average of 935 antibody molecules per liposome. Lung accumulation of 34A-liposomes is completely blocked by a preinjection of free antibody 34A, indicating that the immunoliposome accumulation at the target site is immunospecific. The level of lung accumulation increases ...
Another new technology to increase the accumulation of liposomes at the target site is immunoliposomes. Immunoglobulins, especially those of the IgG class, are attached to the surface of the liposomes. They act as ligands-molecules that connect to a site on a receptor protein-capable of recognizing and binding to tissue at sites of interest. However, most immunoliposomes are still eliminated by the liver before they can deliver significant results. One way to meet this challenge is to use stealth liposome technology: Coat the immunoliposomes with PEG to create long-circulating liposomes. Currently, one immunoliposome formulation is in clinical trials, a PEGylated DXR formulated to recognize gastric, colon, and breast cancer cells ...
The invention discloses a formula of a liposome preparation containing compound amino acids and a preparation method thereof; a raw material mass ratio of the liposome preparation is determined; the preparation method comprises the following steps: (1) weighing soybean phosphatide and cholesterol, adding water, heating and stirring to prepare an oil phase; (2) weighing cysteine hydrochloride and tryptophan, adding process water for dissolution, orderly adding some or all of valine, isoleucine, leucine, lysine acetate, methionine, phenylalanine, threonine, arginine, glycine, and praline; then orderly adding one or more than one of auxiliary materials of vitamin A, vitamin C, vitamin E, and vitamin K, and a film forming material, finally adding potassium sorbate or ethylparaben, stirring toprepare a water phase; (3) mixing the oil phase and the water phase, shearing by a high-speed shearing machine to obtain the liposome preparation. The invention initiates the technology for preparingliposome ...
Soft nanogels are submicron-sized hydrophilic structures engineered from biocompatible polymers possessing the characteristics of nanoparticles as well as hydrogels, with a wide array of potential applications in biotechnology and biomedicine, namely, drug and protein delivery. In this work, nanogels were obtained using the physical self-assembly technique or layer-by-layer which is based on electrostatic interactions. Liposomal vesicles were coated with alternating layers of hyaluronic acid and chitosan yielding a more viscous hydrogel formulation that previously reported core-shell nanoparticulate suspension, via simply modifying the physico-chemical characteristics of the system. Structural features, size, surface charge, stability and swelling characteristics of the nanogel were studied using scanning electron microscopy and dynamic light scattering. With a specific cranio-maxillofacial application in mind, the hydrogel was loaded with recombinant human (rh) bone morphogenetic protein-7, also
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Computer-assisted motion analyses (CASA) and flow cytometry were used to evaluate stallion spermatozoa prior to and after cryopreservation. Spermatozoa were pretreated with: (1) Hepes-buffered medium (SHB); (2) phosphatidylserine (PS) liposomes; or (3) liposomes composed of both PS and cholesterol (PSCH) prior to dilution in either SHB or skim milk-egg yolk extender (SMEY). After cooling to 5 degrees C in SHB, PS and PSCH pretreatment (23%). Spermatozoal motion parameters were higher for spermatozoa diluted in SMEY than dilution in SHB. In Experiment 2, motion parameters were compared for spermatozoa pretreated with PSCH liposomes and cryopreserved in either SMEY or a high salt-skim milk-egg yolk extender (CO). Spermatozoal motion characteristics were similar for all spermatozoal treatments after cooling at 5 degrees C. After cryopreservation, PSCH liposome-treated samples had higher percentages of motile spermatozoa than untreated samples regardless of freezing extender. Samples frozen in CO medium had
The study of different strategies to improve the stability and bioavailability of bioactive components has increased in the last decades. One of the mechanisms that has acquired great relevance is to formulate using liposomal vesicles. Liposomes are structures that enhance the absorption, stability and transport of active compounds, which is reflected by an increase in the bioactivity of the encapsulated molecules. The guarana extract has proven to be rich in methylxanthines and phenolic compounds. These metabolites are associatedto a wide variety of pharmacological properties, and exert a stimulating effect. For this reason, it has become popular in nutritional products. In this workit was characterized physicochemically a nutritional product based on guarana, vitamins and folic acid. In this product the active components were encapsulated in liposomal vesicles, which were analyzed to know their structure, size (diameter) and membrane thickness. Results and analysis indicate that liposomes are ...
Title:Comparison of Physicochemical Properties of Generic Doxorubicin HCl Liposome Injection with the Reference Listed Drug. VOLUME: 18 ISSUE: 4. Author(s):Kuntal Maiti *, Subhas Bhowmick, Pankaj Jain, Murlidhar Zope, Keyur Doshi and Thennati Rajamannar. Affiliation:Sun Pharma Advanced Research Company Ltd., Mumbai, Sun Pharmaceutical Industries Ltd. Mumbai, Sun Pharma Advanced Research Company Ltd., Mumbai, Sun Pharma Advanced Research Company Ltd., Mumbai, Sun Pharma Advanced Research Company Ltd., Mumbai, Sun Pharmaceutical Industries Ltd. Mumbai. Keywords:Doxorubicin hydrochloride, liposome, sterically stable, generic, physicochemical equivalence, cancer.. Abstract:Background: Liposomal doxorubicin is widely used for treating ovarian cancer and Kaposis sarcoma. Encapsulation of doxorubicin in highly complex polyethylene glycol-coated (stealth) liposomes prolongs residence time and avoids the systemic toxicity associated with administration of the free drug. Small variations in ...
In addition, we find binding of charged nanoparticles to the outer surface of phospholipid liposomes produces particle-stabilized liposomes that repel one another and do not fuse. Subsequently, the volume fraction can be raised as high as ∼50%, reversibly, still without fusion. In studies of liposome longevity, we verify the stability of particle-stabilized liposome suspensions with volume fraction up to 16% for up to 50 days, the longest period investigated. In contrast to the stabilized liposomes, the volume fraction of the same liposomes without nanoparticles is typically less than ∼2% with a longevity of 4∼5 days. Fluorescent dyes are encapsulated within the particle-stabilized liposomes, without leakage. Although these particle-stabilized liposomes are stable against fusion, ∼75% of the outer liposome surface remains unoccupied, which is still biofunctionalizable tested with ligand-receptor binding. This work not only provides a robust nanoparticle-liposome complex system which ...
Coating of liposomes with polyethylene glycol (PEG) has proven to prolong the circulation time of liposomes in the blood stream. PEG prevents the binding of opsonins and subsequent uptake of the liposomes by mononuclear phagocytic system (MPS). The reduction in clearance of PEGylated liposomes from the circulation improve the bioavailability of the liposomes in the blood and increase the chance of liposomes being accumulated in tumor tissue by the enhanced permeability and retention effect (EPR). The aim of this study was therefore to investigate the incorporation and retention ability of PEGylated liposome formulations of the anticancer agent Camptothecin (CPT), and further try to develop an immunoliposomal formulation of CPT targeting the EGFR receptors on the surface of colorectal cancer cells. The results from the incorporation and retention studies showed that the formulation consisting of 79 % egg phosphatidylcholine (EPC), 20 % 1,2-di-oleyl-3- trimethylammonium-propane (DOTAP) and 1 % PEG ...
There is a great need of improved anticancer drugs and corresponding drug carriers. In particular, liposomal drug carriers with heat-activated release and targeting functions are being developed for combined hyperthermia and chemotherapy treatments of tumors. The aim of this study is to demonstrate the heat-activation of liposome targeting to biotinylated surfaces, in model experiments where streptavidin is used as a pretargeting protein. The design of the heat-activated liposomes is based on liposomes assembled in an asymmetric structure and with a defined phase transition temperature. Asymmetry between the inside and the outside of the liposome membrane was generated through the enzymatic action of phospholipase D, where lipid head groups in the outer membrane leaflet, i.e. exposed to the enzyme, were hydrolyzed. The enzymatically treated and purified liposomes did not bind to streptavidin-modified surfaces. When activation heat was applied, starting from 22 degrees C, binding of the liposomes
This report aims to target already-existing systems that could enable the use of cloaking concepts in order to achieve control of three-dimensional processes, using coated spheres consisting of concentric layers of homogeneous isotropic diffusivity. Various applications already implicate the use of concentric bilayered vesicles, one example being liposomes used for drug delivery [1]. Liposomes are concentric bilayered vesicles in which an aqueous volume containing a water-soluble drug is enclosed by a membranous lipid bilayer composed of natural or synthetic phospholipids. One popular type of liposomes, known as the stealth liposomes [2], are highly stable, long-circulating liposomes whereby polyethylene glycol has been used as the polymeric steric stabilizer [3]. Stealth and other liposomes use the concept of invisibility in order to hide and evade the immunosystem by coupling water-soluble polymers to the lipid heads. Therefore, the polymer part of the molecule is dissolved in the aqueous ...
Specific targeting of liposome-formulated cytotoxic drugs or antigens to receptors expressed selectively on target cells represents an effective strategy for increasing the pharmacological efficacy of the delivered molecules. We have developed a feasible technique to selectively attach antibodies and fragments thereof, but also small-mol-wt ligands such as peptides, carbohydrates, or any molecules that recognize and bind target antigens or receptors to the surface of small unilamellar liposomes. Our concept is based on the site-specific functionalization of the ligands to be attached to the liposomes by thiol groups. These thiol groups can easily be introduced to antibodies or peptides by addition of cysteines, preferably at sites that do not interfere with the receptor binding domains. Optimally, the site-specific modification is introduced at the C-terminal end of the ligand, separated by an inert spacer sequence located between the thiols and the specific part of the ligand. The ...
DescriptionMethicillin Resistant Staphylococcus aureus (MRSA) causes a myriad of infections ranging from mild skin-infection to more serious infections affecting internal organs. A glycopeptide, Vancomycin, remains the last line of defense against MRSA. The aim of this study is to investigate whether liposomal encapsulated Vancomycin had a better antimicrobial action than free Vancomycin in terms of infection-specific targeting and circulation time. For the same, encapsulation efficiency and release kinetics of the liposomes was evaluated along with Minimum Inhibitory Concentrations (MIC) of the liposomal preparations. The liposomes showcased a 12-15% encapsulation efficiency. Sustained release at pH 6.0 as compared to little to no release at pH 7.4 was demonstrated by the pH sensitive liposomes. Also, in acidic pH, an increase in efficacy was observed with a greater decrease in the MIC of the pH responsive liposomes as compared to the lower decrease in MIC of the non pH-responsive liposomes and ...
The liposome, a closed phospholipid bilayered vesicular system, has received considerable attention as a pharmaceutical carrier of great potential over the past 30 years. The ability of liposomes to encapsulate both hydrophilic and hydrophobic drugs, coupled with their biocompatibility and biodegradability, make liposomes attractive vehicles in the field of drug delivery. In addition, great technical advances such as remote drug loading, triggered release liposomes, ligand-targeted liposomes, liposomes containing combinations of drugs, and so on, have led to the widespread use of liposomes in diverse areas as delivery vehicles for anti-cancer, bio-active molecules, diagnostics, and therapeutic agents ...
In one method, DNA fragments, of approximately 2-200 bases in length, or deoxynucleotides (single bases), are administered topically to the epidermis, either in a liposome preparation or in another appropriate vehicle, such as propylene glycol, in a quantity sufficient to enhance melanin production. As used herein, "DNA fragments" refers to single-stranded DNA fragments, double-stranded DNA fragments, a mixture of both single-and double-stranded DNA fragments, or deoxynucleotides. "Deoxynucleotides" refers to either a single type of deoxynucleotide or a mixture of different deoxynucleotides. The DNA fragments or deoxynucleotides can come from any appropriate source. For example, salmon sperm DNA can be dissolved in water, and then the mixture can be autoclaved to fragment the DNA. The fragments can additionally be UV-irradiated. The liposome preparation can be comprised of any liposomes which penetrate the stratum corneum and fuse with the cell membrane, resulting in delivery of the contents of ...
There are about 20 publications about liposomal formulations of Cyclosporin A (CyA) in the pharmaceutical and preclinical literature. Liposomal formulations were developed in order to reduce the nephrotoxicity of CyA and to increase pharmacological effects. However, conflicting results have been published as to the therapeutic properties of these formulations. This is also true for the change in pharmacokinetics and organ distribution of the liposomally encapsulated CyA as compared to conventionally formulated CyA. Using biophysical methods, it could be shown that CyA is not tightly entrapped in liposomal membranes, despite its high lipophilicity. CyA shows retardation only at high lipid concentrations in blood, following a massive injection of liposomes.This effect may diminish nephrotoxicity, as could be demonstrated by in vitro studies using a model tubule system. The results of these studies can be used to predict the formulation behavior in vivo and to optimize liposomal formulations. When ...
Elixinols new rapidly dissolving Hemp Oil Liposomes are the latest enhancements to cannabinoid delivery. Now you can receive cannabinoids into the body faster, deeper and easier than ever before. With 100% natural fruit and herb extracts, this is a delicious hemp oil supplement you will enjoy taking daily without any bitter taste.Product informationThis 3.5 oz (100 ml) spray pump dispenser bottle of Elixinol™ Liposome contains 1000 mg of cannabidiol extract (CBD hemp oil) with a citrus flavor.How our hemp oil liposomes are madeWe pre-dissolve our CBD hemp oil and embed it into microscopic liposomes. This safe technology allows you to absorb more cannabinoids with the aid of naturally occurring phospholipids. These support cellular health and delivery of cannabidiol and other cannabinoids directly into the cell.The reason that liposomes are so effective is that hemp oil, in its natural form, is a sticky dense oil. As you may know, getting any oil-based substance to pass through a cell wall is a
Read "DNA-Induced Aggregation and Fusion of Phosphatidylcholine Liposomes in the Presence of Multivalent Cations Observed by the Cryo-TEM Technique, The Journal of Membrane Biology" on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.
Much of the work on liposomal drug delivery has focused on cancer treatment because conventionally delivered cancer chemotherapy has been far from satisfactory. Major problems with conventional chemotherapy are the inability of the drug to reach the tumor site at pharmacologically active concentrations, intrinsic as well as acquired cross-resistance to multiple chemotherapeutic agents, and toxicity that contributes to many of the treatment failures.. Doxorubicin encapsulated in long-circulating, PEGylated liposomes has proven to be more effective than the free drug in several tumor models, including murine tumors and human tumor xenografts, regardless of tumor type and site of implantation (27) . In all of the experiments conducted, the liposomal preparation clearly performed better than Free-Dox, and the peak tumor drug levels obtained by liposome delivery were at least 3-fold greater. Notable differences in toxicity between free drug and liposomal drug have also been observed, including ...
Kawakami, S.; Suzuki, S.; Yamashita, F.; Hashida, M., 2005: Induction of apoptosis in A549 human lung cancer cells by all-trans retinoic acid incorporated in DOTAP/cholesterol liposomes
TY - JOUR. T1 - Direct Comparison of Standard Transmission Electron Microscopy and Cryogenic-TEM in Imaging Nanocrystals Inside Liposomes. AU - Li, Tang. AU - Nowell, Cameron J.. AU - Cipolla, David. AU - Rades, Thomas. AU - Boyd, Ben J.. PY - 2019/4/1. Y1 - 2019/4/1. N2 - The use of electron microscopy techniques in the understanding of shape and size of nanoparticles are commonly applied to drug nanotechnology, but the type of microscopy and suitability for the particles of interest can have a significant impact on the result. The size and shape of the nanoparticles are crucial in clinical applications; however, direct comparison of the results from standard transmission electron microscopy (TEM) and cryo-TEM have rarely been reported. As a useful case for comparison, liposomal drug nanocrystals are studied here. In this study, the effect of thawing temperature on the size and shape of the ciprofloxacin nanocrystals was determined. A quantitative standard TEM assay was developed to allow for ...
A new technique for the quantification of cellular receptor-mediated endocytosis has been developed based on the analysis by flow cytometry of ligand-bearing liposomes containing the fluorochrome carboxyfluorescein. Carboxyfluorescein encapsulated at high concentrations in protein A-bearing liposomes is self-quenched. Binding and internalization of such liposomes by cells via antibodies directed towards membrane surface determinants results in the release of the liposome-encapsulated carboxyfluorescein into the cytoplasm causing an increase in cell-associated fluorescence. This increase can be quantified on a flow cytofluorometer. ...
Consumer information about the medication CYTARABINE LIPOSOME - INJECTION (Depocyt), includes side effects, drug interactions, recommended dosages, and storage information. Read more about the prescription drug CYTARABINE LIPOSOME - INJECTION.
The efficacy of a liposomal formulation for intracerebral delivery of borocaptate (BSH) to brain tumor cells has been investigated using cell culture to study BSH uptake and persistence and using tumor-bearing rats to determine BSH distribution in the brain. During a 16-hr incubation, cellular uptake of BSH solution or BSH liposomal formulation was similar. However, the cellular persistence of BSH greatly increased when BSH was present in liposome. The differences in cellular persistence for BSH solution and BSH-loaded liposomes were significant both in 12-hr and 24-hr incubation experiments (p | 0.05 and p | 0.01, respectively). For the studies involving tumor-bearing rats, BSH level in tumor tissue was significantly higher than that in normal brain tissue at 2 hr and 6 hr after intracerebral injection of BSH-loaded liposomes (p | 0.01). Our study indicated that the liposomal formulation enhanced cellular persistence of BSH in tumor cells and therefore favored the boron accumulation in the cells. With
1. Matsumura Y, Maeda H. A new concept for macromolecular therapeutics in cancer chemotherapy: mechanism of tumoritropic accumulation of proteins and the antitumor agent smancs. Cancer Res. 1986;46:6387-92 2. Maeda H. The enhanced permeability and retention (EPR) effect in tumor vasculature: the key role of tumor-selective macromolecular drug targeting. Adv Enzyme Regul. 2001;41:189-207 3. Maeda H. Macromolecular therapeutics in cancer treatment: the EPR effect and beyond. J Controlled Release. 2012;164:138-44 4. Harrington KJ, Mohammadtaghi S, Uster PS, Glass D, Peters AM, Vile RG. et al. Effective targeting of solid tumors in patients with locally advanced cancers by radiolabeled pegylated liposomes. Clin Cancer Res. 2001;7:243-54 5. Allen C. Why Im holding onto hope for nano in oncology. Mol Pharm. 2016;13:2603-4 6. Minchinton AI, Tannock IF. Drug penetration in solid tumours. Nat Rev Cancer. 2006;6:583-92 7. Tan Q, Saggar JK, Yu M, Wang M, Tannock IF. Mechanisms of drug resistance related ...
We present a novel thylakoid based bio-solar cell capable of generating a photoelectric current of 0.7 µA/cm2. We have introduced an electro conductive polymer, PEDOT-S, to the thylakoid membrane. PEDOT-S intervenes in the photosynthesis, captures electrons from the electron transport chain and transfers them directly across the thylakoid membrane, thus generating a current. The incorporation of the electro conductive polymer into the thylakoid membrane is therefore vital for the function of the bio-solar cell. A liposomal model system based on liposomes formed by oleic acid was used to develop and study the incorporation of PEDOT-S to fatty acid membranes. The liposomes allow for a more controllable and easily manipulated system compared to the thylakoid membrane. In the model system, PEDOT-S could successfully be incorporated to the membrane, and the developed methods were applied to the real system of thylakoid membranes. We found that a bio-compatible electrolyte and redox couple was ...
Colloidal and interfacial phenomena lie at the core of drug formulation, drug delivery, as well as drug binding and action at diseased sites, e.g., in cancer therapy. We review a class of liposome-based drug-delivery systems whose design and functional properties are intimately controlled by the stability of sub-micron structures, lipid-bilayer interfaces, and interfacially activated enzymes that can be exploited to target and deliver drugs. Moreover these drugs can themselves be special lipid molecules in the form of lipid prodrugs that both form the liposomal carrier as well as the substrate for endogenously upregulated lipases that turn the prodrugs into potent drugs precisely at the diseased site. ...
Proteins and polysaccharide components were colocalized through a liposomal delivery system. LEPS liposomal carriers were composed of DOPC/DOPG/DOGS-NTA-Ni/cholesterol/DSPE-PEG2000 at a molar ratio of 3:3:1:4:0.1 to a total lipid mass of 500 μg. After dissolving lipids in chloroform, the solution was sonicated for 1 min using a Branson 450D Sonifier (at 20% amplitude using a tapered tip) and then evaporated using a rotary evaporator to form a film. Lipids were then rehydrated with phosphate-buffered saline (PBS) containing the polysaccharide antigens to form liposomes, which were then passed 10 to 12 times through a handheld extruder (Avanti Polar Lipids) with a pore size of 200 nm. On ice, the background liposome solution was passed twice through a filter with 50-nm pore size and replaced each time with PBS. Next, proteins were incubated with liposomes for 30 min at 4°C with surface attachment mediated via polyhistidine tag-Ni chelation. CRM197 was included in the LEPS formulations used for ...
The influence of vitamin D3 and its metabolites calcifediol (25(OH)D) and calcitriol on immune regulation and inflammation is well described, and raises the question of potential benefit against bacterial infections. In the current study, 25(OH)D was encapsulated in liposomes to enable aerosolisation, and tested for the ability to prevent pulmonary infection by Pseudomonas aeruginosa. Prepared 25(OH)D-loaded liposomes were nanosized and monodisperse, with a negative surface charge and a 25(OH)D entrapment efficiency of approximately 23%. Jet nebulisation of liposomes was seen to yield an aerosol suitable for tracheo-bronchial deposition. Interestingly, 25(OH)D in either liposomes or ethanolic solution had no effect on the release of the proinflammatory cytokine KC from Pseudomonas-infected murine epithelial cells (LA-4); treatment of infected, human bronchial 16-HBE cells with 25(OH)D liposomes however resulted in a significant reduction in bacterial survival. Together with the importance of ...
Giant Unilamellar Vesicles (GUVs) prepared from phospholipids are becoming popular membrane model systems for use in biophysical studies. The quality, size and yield of GUVs depend on the preparation method used to obtain them. In this study, hydrogels consisting of dextran polymers crosslinked by poly(ethyl
PEG altered the pharmacokinetic property of the DSPC/cholesterol liposomal doxorubicin by decreasing the Vss and clearance, and thereby increasing plasma AUC. These results are consistent with the notion that sterically stabilized liposome may reduce the RES uptake and enhance the longevity of liposomal doxorubicin in circulation, but above 3%, the gain in pharmacokinetic advantage was only slight. Compared with conventional liposomes, sterically stabilized liposomes have a 100-fold increase in AUC (3) . However, for the DSPC system used in this study, the AUC of liposomal doxorubicin with 6% PEG-modified lipid was only approximately twice that of liposomal doxorubicin without PEG, regardless of dosage or tumor-bearing status. Daunorubicin liposomes composed of DSPC/cholesterol without PEG also had a similar AUC (20) . The higher transition temperature and homogeneity in fatty acid of DSPC confers the higher stability to this DSPC/cholesterol liposomal system.. The movement of drugs from the ...
The use of liposomes has been crucial for investigations in biomimetic chemical biology as a membrane model and in medicinal chemistry for drug delivery. Liposomes are made of phospholipids whose biophysical characteristics strongly depend on the type of fatty acid moiety, where natural unsaturated lipids always have the double bond geometry in the cis configuration. The influence of lipid double bond configuration had not been considered so far with respect to the competence of liposomes in delivery. We were interested in evaluating possible changes in the molecular properties induced by the conversion of the double bond from cis to trans geometry. Here we report on the effects of the addition of trans-phospholipids supplied in different amounts to other liposome constituents (cholesterol, neutral phospholipids and cationic surfactants), on the size, ζ-potential and stability of liposomal formulations and on their ability to encapsulate two dyes such as rhodamine B and fluorescein. From a
Liposomes are proposed as drug delivery systems and can in principle be designed so as to cohere with specific tissue types or local environments. However, little detail is known about the exact mechanisms for drug delivery and the distributions of drug molecules inside the lipid carrier. In the current work, a coarse-grained (CG) liposome model is developed, consisting of over 2500 lipids, with varying degrees of drug loading. For the drug molecule, we chose hypericin, a natural compound proposed for use in photodynamic therapy, for which a CG model was derived and benchmarked against corresponding atomistic membrane bilayer model simulations. Liposomes with 21-84 hypericin molecules were generated and subjected to 10 microsecond simulations. Distribution of the hypericins, their orientations within the lipid bilayer, and the potential of mean force for transferring a hypericin molecule from the interior aqueous droplet through the liposome bilayer are reported herein.. ...
in Journal of Biological Chemistry (1996), 271(46), 28757-65. A series of natural peptides and mutants, derived from the Alzheimer beta-amyloid peptide, was synthesized, and the potential of these peptides to induce fusion of unilamellar lipid vesicles was ... [more ▼]. A series of natural peptides and mutants, derived from the Alzheimer beta-amyloid peptide, was synthesized, and the potential of these peptides to induce fusion of unilamellar lipid vesicles was investigated. These peptide domains were identified by computer modeling and correspond to respectively the C-terminal (e.g. residues 29-40 and 29-42) and a central domain (13-28) of the beta-amyloid peptide. The C-terminal peptides are predicted to insert in an oblique way into a lipid membrane through their N-terminal end, while the mutants are either parallel or perpendicular to the lipid bilayer. Peptide-induced vesicle fusion was demonstrated by several techniques, including lipid-mixing and core-mixing assays using pyrene-labeled ...
in Journal of Biological Chemistry (1996), 271(46), 28757-65. A series of natural peptides and mutants, derived from the Alzheimer beta-amyloid peptide, was synthesized, and the potential of these peptides to induce fusion of unilamellar lipid vesicles was ... [more ▼]. A series of natural peptides and mutants, derived from the Alzheimer beta-amyloid peptide, was synthesized, and the potential of these peptides to induce fusion of unilamellar lipid vesicles was investigated. These peptide domains were identified by computer modeling and correspond to respectively the C-terminal (e.g. residues 29-40 and 29-42) and a central domain (13-28) of the beta-amyloid peptide. The C-terminal peptides are predicted to insert in an oblique way into a lipid membrane through their N-terminal end, while the mutants are either parallel or perpendicular to the lipid bilayer. Peptide-induced vesicle fusion was demonstrated by several techniques, including lipid-mixing and core-mixing assays using pyrene-labeled ...
LIPOSOMES PHYTO-SERUM REVITALISANT Anti-wrinkle, firming and moisturising serum based on Liposomes with natural herbal extracts. Specially developed to prevent premature aging of the skin and loss of elasticity. Wrinkles are smoothed and the skin is better hydrated and less fragile. Suitable for all skin types. Can be
A fusogenic liposome composition for delivering a liposome-entrapped compound into the cytoplasm of a target cell is described. The liposomes have an outer surface coating of …chemically releasable hydrophilic polymer chains which shield hydrophobic polymers on the liposome outer surface. Release of the hydrophilic polymer chains exposes the hydrophobic polymers for interaction with outer cell membranes of the target cells to promote fusion of the liposome with the target cells. Also disclosed is a method for using the composition to deliver a compound to target cells, and a method for selecting suitable hydrophobic polymers for use in the composition. (MORE) ...
A process for the preparation of proteoliposomes comprising: (1) mixing a fusogen with lipid components used to form unilamellar lipid vesicles to thereby form fusogenic unilamellar lipid vesicles; an
The (Na+ +K+)-activated, Mg2+-dependent ATPase from rabbit kidney outer medulla was prepared in a partially inactivated, soluble form depleted of endogenous phospholipids, using deoxycholate. This preparation was reactivated 10 to 50-fold by sonicated liposomes of phosphatidylserine, but not by non-sonicated phosphatidylserine liposomes or sonicated phosphatidylcholine liposomes. The reconstituted enzyme resembled native membrane preparations of (Na+ +K+)-ATPase in its pH optimum being around 7.0, showing optimal activity at Mg2+:ATP mol ratios of approximately 1 and a Km value for ATP of 0.4 mM. Arrhenius plots of this reactivated activity at a constant pH of 7.0 and an Mg2+: ATP mol ratio of 1:1 showed a discontinuity (sharp change of slope) at 17 degrees C, with activation energy (Ea) values of 13-15 kcal/mol above this temperature and 30-35 kcal below it. A further discontinuity was also found at 8.0 degrees C and the Ea below this was very high (greater than 100 kcal/mol). Increased Mg2+ ...
Page contains details about RG7 mAb-conjugated Cy5-labeled soy phosphatidylcholine/cholesterol/1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[carboxy(polyethylene glycol)-2000] lipid-based nanoparticles-anti-mouse CD4-PE (clone GK1.5) complex . It has composition images, properties, Characterization methods, synthesis, applications and reference articles : nano.nature.com
Exponentially growing human melanoma cells (M14 cell line) were pretreated with various amounts of dipalmitoylphosphatidylcholine-containing multilamellar liposomes and then exposed to heat treatment (42.5°C). Cell damage produced by the treatments, given separately or in combination, was evaluated in terms of cell survival.. Our results demonstrate that the cell survival at 37°C was not affected by liposome concentrations up to 1000 nmol of phospholipid/2.5 × 106 cells, while liposome treatment of cells before heat exposure determined a marked damaging effect even at 100 nmol of phospholipid/2.5 × 106 cells.. The mechanisms of liposome-cell interaction have been investigated by electron microscopy or by electron spin resonance measurements of spin-labeled membranes of intact cells. Evidence has been obtained that liposomal lipids are either taken up by M14 cells or become incorporated in the cell membrane.. The present data suggest the possibility that liposome treatments per se could be of ...
We have examined the interactions of hemoglobin containing liposomes and of liposomes composed of polymerizable phospholipids with blood cells and proteins. All types of liposomes studied bound a variety of serum proteins with IgG being the most abundant component in each case. Polymerized methacrylate liposomes specifically bound a 53 kilodalton protein not bound by other liposome types. None of the liposomes tested provoked platelet aggregation; however, unpolymerized methacrylate liposomes markedly inhibited ADP induced platelet aggregation. Most liposomes tested did not affect clotting of plasma; however, polymerized methacrylate liposomes bound clotting factor V and thus inhibited clotting.*BLOOD PLATELETS
The efficiency of encapsulating a drug into a liposomal formulation is increased by use of a lipid having a carbon chain containing from about 13 to about 28 carbons during preparation of the liposomes. Preferably the liposomes are multivesicular liposomes.
The efficiency of encapsulating a drug into a liposomal formulation is increased by use of a lipid having a carbon chain containing from about 13 to about 28 carbons during preparation of the liposomes. Preferably the liposomes are multivesicular liposomes.