MICROENCAPSULATION OF MAMMALIAN-CELLS IN A HEMA-MMA COPOLYMER - EFFECTS ON CAPSULE MORPHOLOGY AND PERMEABILITY
MICROENCAPSULATION OF MAMMALIAN-CELLS IN A HEMA-MMA COPOLYMER - EFFECTS ON CAPSULE MORPHOLOGY AND PERMEABILITY
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DOI：
10.1002/jbm.820240908
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发表时间：
1990-09-01
期刊：
影响因子：
--
通讯作者：
SEFTON, MV
中科院分区：
文献类型：
--
作者：
CROOKS, CA;DOUGLAS, JA;SEFTON, MV
A new process for preparing uniform microcapsules with a hydroxyethyl methacrylate-methyl methacrylate copolymer (HEMA-MMA) has been devised. Capsule diameters were 900-1000 .mu.m in diameter, (.+-. 10-20 .mu.m, .+-. SD) depending on the precipitation conditions. The process involved the coextrusion of polymer solution (in PEG 200) and the mammalian cell suspension (here erythrocytes) through a needle assembly which is submerged in a layer of hexadecane which is in turn sitting above a stirred isotonic aqueous solution in a volumetric flask. The needle is repeatedly withdrawn from the hexadecane overlayer shearing a droplet from the needle tip which falls into the water, where the solvent is extracted to precipitate the polymer around the cells to yield the capsules. The morphology of the capsule wall was altered by changing the precipitation bath from phosphate buffered saline (PBS) to 0.3 M glycerol. This resulted in greater macroporosity in the wall, presumably because of the faster precipitation due to the higher solvent/precipitant compatibility with 0.3 M glycerol. The permeability to a series of test solutes (glucose, inulin, albumin, and alcohol dehydrogenase, ADH) increased by a factor of .apprx. 2, presumably because of the increased macroporosity. Addition of 15% water to the polymer solvent enhanced the macroporosity, presumably by bringing the system closer to the cloud point; however, there was no corresponding increase in permeability. There was a significant decrease in permeability between that of albumin (.apprx. 69,000 D) and ADH (.apprx. 150,000 D) suggesting that the molecular weight cutoff of these capsules was on the order of 100,000 D as desired. This process is now being evaluated for the encapsulation of pancreatic islets and other cells of potential clinical interest.
