Encapsulation lipid vesicles

Keywords Artificial cells Encapsulation Lipid vesicles Membranes... 

D. (1978). Effect of lipid vesicle (liposome) encapsulation of methotrexate on its chemotherapeutic efficacy in solid rodent tumors. Cancer Res., 38, 2848-2853. 

The Jing group investigated their poly(L-lysine)-6-poly(L-phenylalanine) vesicles for the development of synthetic blood, since PEG-lipid vesicles were previously used to encapsulate hemoglobin to protect it from oxidation and to increase circulation time. They extended this concept and demonstrated that functional hemoglobin could be encapsulated into their vesicles. The same polypeptide material was also used to complex DNA, which caused the vesicles to lose their... 

Use of encapsulated labeled precursors in lipid vesicles enabled the Hawaiian group to conduct the biosynthetic studies - with the exception of workup of the sponge - entirely in the field. Incorporation of doubly labeled [13C, 15N]cyanide into a Ciocalypta sp. and an Acanthella sp. produced labeled 9-isocyanoneopupukeanane (77) and kalihinol-F (112) respectively [71]. Detection of incorporation was followed by 13C NMR experiments. 

Liposome conjugates may be used in various immunoassay procedures. The lipid vesicle can provide a multivalent surface to accommodate numerous antigen-antibody interactions and thus increase the sensitivity of an assay. At the same time, it can function as a vessel to carry encapsulated detection components needed for the assay system. This type of enzyme-linked immunosorbent assay (ELISA) is called a liposome immunosorbent assay or LISA. One method of using liposomes in an immunoassay is to modify the surface so that it can interact to form biotin-avidin or biotin-streptavidin complexes. The avidin-biotin interaction can be used to increase detectability or sensitivity in immunoassay tests (Chapter 23) (Savage et al., 1992). 

Satoh T, Kobayashi K, Sekiguchi S, et al. Characteristics of artificial red cells. Hemoglobin encapsulated in poly-lipid vesicles. ASAIO J 1992 38 M580. 

Takeoka S, Teramura Y, Atoji T, et al. Effect of Hb-encapsulation with vesicles on H202 reaction and lipid peroxidation. Bioconugate Chem 2002 13 1302. 

Semple SC, Klimuk SK, Harasym TO, et al. Efficient encapsulation of antisense oligonucleotides in lipid vesicles using ionizable aminolipids formation of novel small multilamellar vesicle structures. Biochim Biophys Acta 2001 1510 152. 

Jay, D. and Gilbert, W. (1987). Basic protein enhances the encapsulation of DNA into lipid vesicles model for the formation of primordial cells. Proc. Natl. Acad. Sci. 

Nomura, S. M., Tsumoto, K., Yoshikawa, K., Ourisson, G., and Nakatani, Y. (2002). Towards proto-cells primitive lipid vesicles encapsulating giant DNA and its histone complex. Cell. Mol. Biol. Lett., 7, 245-6. 

The permeability of solutes across lipid bilayers is a product of the partition coefficient and the transverse diffusion coefficient [30]. Bilayer polymerization can alter solute diffusion by modifying either or both of these processes. In order to examine the effect of polymerization on bilayer permeability a nonionic solute of moderate permeability, [3H-glucose], was encapsulated in the vesicles prior to polymerization, removed from the exterior after polymerization, and its permeation across the bilayer was measured periodically [31]. Quantitative measurements of the 3H-glucose leakage revealed that the formation of linear polymer chains from methacryloyl lipids reduced the permeability coefficient to 0.3 to 0.5 of that of the unpolymerized lipid vesicles. A larger reduction (two orders of magnitude) was only found when crosslinked polymer networks were formed [31]. 

Virosomes are viral glycoproteins encapsulated in lipid vesicles, which have been shown to be effective as experimental vaccines delivered by both mucosal and systemic routes. Viruses and their surface glycoproteins have a high affinity for receptors on mucosal surfaces, especially along the respiratory tract. 

Several reports in the literature have indicated that transdermal delivery may be further increased by combining chemical excipients with electroporation. These investigations included macromolecules like dextrans [58], cyclodextrins [59] and even simple salts such as calcium chloride [60]. Other workers have, however, looked at encapsulation of compounds within lipid vesicles (liposomes) as potential candidates for electroporation-mediated delivery [61,62]. A fuller treatment of this combination is described in Chapter 17. 

Polymeric vesicles, or polymersomes, are of interest for the encapsulation and delivery of active ingredients. They offer enhanced stability and lower permeability compared to lipid vesicles, and the versatility of synthetic polymer chemistry provides the ability to tune properties such as membrane thickness, surface... 

Xu D, Cheng Q (2002) Surface-bound lipid vesicles encapsulating redox species for ampero-metric biosensing of pore-forming bacterial toxins. J Am Chem Soc 124 14314-14315... 

Even if membranous vesicles were commonplace on the early Earth and had sufficient permeability to permit nutrient transport to occur, these structures would be virtually impermeable to larger polymeric molecules that were necessarily incorporated into molecular systems on the pathway to cellular life. The encapsulation of macromolecules in lipid vesicles has been demonstrated by hydration-dehydration cycles that simulate an evaporating lagoon [53] or by freeze-thaw cycles [54]. Molecules as large as DNA can be captured by such processes. For instance, when a dispersion of DNA and fatty acid vesicles is dried, the vesicles fuse to form a multilamellar sandwich structure with... 

Fig. 6 Macromolecules are readily encapsulated in lipid vesicles in a single cycle of dehydration-hydration [53]. Such wetting-drying cycles would have commonly occurred in the prebiotic environment at intertidal zones...

Most recently, functioning translation systems that included ribosomes have been encapsulated in lipid vesicles. The first attempt to assemble a translation system in a lipid vesicle system was made by Oberholzer et al. [84], However, only very small amounts of peptides were synthesized, largely because the lipid bilayer was impermeable to amino acids, so that ribosomal translation was limited to the small number of amino acids encapsulated within the vesicles. Yu et al. [85] and Nomura et al. [86] improved the yield... 

Fig. 11 Lipid vesicles with encapsulated T7 RNA polymerase and DNA template. A mixture of four nucleoside triphosphates was added, and these diffused into the vesicles and were used by the polymerase to synthesize RNA with DNA as a template. The RNA was stained with ethidium bromide and appears as fluorescent material within the vesicles. Note that some of the vesicles do not contain fluorescent RNA, presumably because they lacked sufficient enzyme or template. Scale bar shows 20 pm...

Mezei, M., and Nugent, F. J. (1984), Method of encapsulating biologically active materials in multilmellar lipid vesicles, U.S. Patent 4,485,054. 

In vivo gene expression in animals has been obtained after introduction of DNA encapsulated in liposomes, which are lipid vesicles that entrap the DNA. Further, tissue and cell type specificity has been conferred on the liposomes by coupling to cell-type specific antibodies, resulting in immunoliposom es°. In some cases a combination of liposomes and red blood cell membranes has been used for delivery (Feigner and Rhodes, 1991). 

Wijaya, A. and Hamad-Schifferli, K. (2007). High-Density Encapsulation of Fe304 Nanoparticles in Lipid Vesicles. Langmuir 23 9546-9550. 

On the contrary, they argue that the specifically elastic properties of thetransfersomes are thecrucial features that allow the lipid vesicle to carry the encapsulated agent across the skin. ... 

Liposome A closed lipid vesicle surrounding an aqueous interior it may be used to encapsulate exogenous materials for their ultimate delivery into cells by fusion with the cell. 

We have developed and used specially formulated, highly fusogenic, unilamellar lipid vesicles that contain magnesium-ATP for intracellular ATP delivery, and preliminary results indicate that this new energy delivery technique can provide a significant protective effect to ischemic tissues. This article reports our encapsulation process and preliminary results with the new ATP delivery technique. 

To determine the ability of the ATP-vesicles fusion with the cell membrane, HUVECs were cultured with the lipid vesicles, in which carboxyflnorescein was encapsulated. Within 10 min, the water-solnble carboxyflnorescein filled inside the cells (4). 

Drug Delivery - The most widely studied method of reducing toxicity of antitumor agents has continued to be encapsulation in liposomes. The mechanism of drug toxicity reduction and pharmacokinetics of liposome-encapsulated drugs have been reviewed.Methotrexate in lipid vesicles enhanced absorption in tumor cells vitro and resulted in 80% tumor reduction in mice bearing a P1798 lymphosarcoma, a tumor resistant to the same amount of free methotrexate. The unstable nature of aqueous suspensions of CCNU was overcome and the duration of dru action increased, when it was formulated with phosphatidyl choline. Tar-... 

Deamer, D. W. and Barchfeld, G. L. (1982). Encapsulation of maeromolecules by lipid vesicles under simulated prebiotic conditions. Journal of Molecular Evolution, 18, 203-6. 

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