Microparticles cell encapsulation

LS and CLS are solid microparticles with a mean diameter usually between 0.2 and 500 pm, composed of a solid hydrophobic fat matrix in which (in the case of LS) the bioactive compound or compounds are dissolved or dispersed. Because of their large range in particle size, LS can be administered by different routes, such as orally, subcutaneously, intramuscularly, or topically, or they can be used for cell encapsulation, thus allowing them to be proposed for treatment of a number of diseases [26-28], The in vivo distribution of LS demonstrated a high affinity to vascular wells (including capillaries), to inflamed tissues, and to granulocytes [29,30],... 

As for animal cell entrapment in hydrogel microparticles or microcapsules, encapsulation procedure should proceed under physiological conditions within a short time (20-30 min), in order to provide cell viability, and to be as simple as possible because all manipulations are carried out under strictly sterile conditions. Taking into account all these requirements, it should be noted that the list of polymer materials and methods for animal cell encapsulation is rather limited. So-called alginate-based carriers (microparticles, micro- and nanocapsules) assure the favorable polymer systems for animal cell immobilization. 

Methods for forming microparticles containing encapsulated cells have been described. The cells may be encapsulated in a microcapsule that includes an internal cell core containing polysaccharide gum surrounded by a semipermeable membrane (22). The microcapsule is made from alginate in combination with polylysine, poly-omithine. 

Qiu C, Chen M, Yan H, Wu HK. Generation of uniformly sized alginate microparticles for cell encapsulation hy using a soft-lithography approach. Adv Mater 2007 19(12) 1603-7. 

Additionally, acid-degradable protein delivery vehicles have been synthesized via ADMET polymerization [126]. In this work, ADMET was used to form polyketals and polyacetals, which possessed the physical properties necessary for microparticle formulation. Using a double emulsion procedure, the enzyme, which catalyzes the decomposition of hydrogen peroxide to water and oxygen, was encapsulated into these microparticles. Cell studies demonstrated that these microparticles dramatically improved the ability of the catalase to scavenge hydrogen peroxide produced by macrophages. 

Applications of microparticles can be found in medicine, biochemistry, colloid chemistry, and aerosol research [48]. Some uses include separation media for chromatographic application, high surface area substrates for immobilized enzymes, standards for calibration, spacers in optical cavities and liquid crystal displays, and three-dimensional microenvironments for cell encapsulation. It should be stressed that even a scaled-up MF synthesis enables generation of a relatively small amount of particles, in comparison with conventional emulsion, dispersions, or suspension polymerizations. Thus, most practical applications of such microbeads should utilize their high-value unique properties, for example, a uniform distribution of sizes and control of morphology, structure, and shape. Therefore, some of the demonstrated applications of polymer microbeads are still in the proof-of-concept stage. 

Eun, Y.-J. et al (2010) Encapsulating bacteria in agarose microparticles using microfluidics for high-throughput cell analysis and isolation. AC5 Chem. Biol, 6 (3), 260-266. 

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