title: Preparation of uniform-sized PELA microspheres with high encapsulation efficiency of antigen by premix membrane emulsification.
abstract: Relatively uniform-sized poly(lactide-co-ethylene glycol) (PELA) microspheres with high encapsulation efficiency were prepared rapidly by a novel method combining emulsion-solvent extraction and premix membrane emulsification. Briefly, preparation of coarse double emulsions was followed by additional premix membrane emulsification, and antigen-loaded microspheres were obtained by further solidification. Under the optimum condition, the particle size was about 1 mum and the coefficient of variation (CV) value was 18.9%. Confocal laser scanning microscope and flow cytometer analysis showed that the inner droplets were small and evenly dispersed and the antigen was loaded uniformly in each microsphere when sonication technique was occupied to prepare primary emulsion. Distribution pattern of PEG segment played important role on the properties of microspheres. Compared with triblock copolymer PLA-PEG-PLA, the diblock copolymer PLA-mPEG yielded a more stable interfacial layer at the interface of oil and water phase, and thus was more suitable to stabilize primary emulsion and protect coalescence of inner droplets and external water phase, resulting in high encapsulation efficiency (90.4%). On the other hand, solidification rate determined the time for coalescence during microspheres fabrication, and thus affected encapsulation efficiency. Taken together, improving the polymer properties and solidification rate are considered as two effective strategies to yield high encapsulation.
authors.affiliation: State Key Lab of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, PR China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wei
authors.forename: Wei
authors.initials: W
authors.lastname: Wei
authors.forename: Rui
authors.initials: R
authors.lastname: Tian
authors.forename: Lian-Yan
authors.initials: LY
authors.lastname: Wang
authors.forename: Zhi-Guo
authors.initials: ZG
authors.lastname: Su
authors.forename: Guang-Hui
authors.initials: GH
authors.lastname: Ma
mesh_terms: D000941:Antigens / Q000737:chemistry*; D004337:Drug Carriers; D004655:Emulsions; D004867:Equipment Design; D005434:Flow Cytometry / Q000379:methods; D007773:Lactates / Q000737:chemistry*; D008422:Materials Testing; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D015233:Models, Statistical; D008970:Molecular Weight; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry
chemical_list: D000941:Antigens; D004337:Drug Carriers; D004655:Emulsions; D007773:Lactates; D011108:Polymers; C088513:poly(lactic acid-ethylene glycol); D011092:Polyethylene Glycols