title: Alginate/aminopropyl-silicate/alginate membrane immunoisolatability and insulin secretion of encapsulated islets.
abstract: We utilized the sol-gel reaction to prepare an immunoisolatable membrane for a microcapsule-shaped bioartificial pancreas. The membrane, derived from two precursors, 3-(aminopropyl)trimethoxysilane (APTrMOS) and tetramethoxysilane (TMOS), was formed onto calcium-alginate gel beads via electrostatic interaction. The molecular weight cutoff point of less than 150 000 required for immunoisolation was achieved at molar ratios ([APTrMOS]/[TMOS]) ranging from 0.60 to 2.40 with the amount of APTrMOS fixed at 3.40 mmol/(10 mL of calcium-alginate). When encapsulated in a membrane prepared at the molar ratio of 0.60, the islets contracted in volume and showed no response to stimulation by a high glucose concentration. However, islets in a membrane prepared at the molar ratio of 2.40 showed no contraction and responded to the glucose stimulation at almost the same level as free islets. These results demonstrated that the molar ratio of the precursors was a dominant factor affecting membrane permeability and the insulin secretion activity of the encapsulated islets.
authors.affiliation: Department of Materials Process Engineering, Graduate School of Engineering, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan. sakai@chem-eng.kyushu-u.ac.jp
authors.forename: Shinji
authors.initials: S
authors.lastname: Sakai
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Ono
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ijima
authors.forename: Koei
authors.initials: K
authors.lastname: Kawakami
mesh_terms: D001672:Biocompatible Materials; D002118:Calcium / Q000737:chemistry; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000166:cytology / Q000378:metabolism*; D008422:Materials Testing; D008567:Membranes, Artificial; D008863:Microspheres; D008970:Molecular Weight; D019397:Pancreas, Artificial; D010539:Permeability; D011437:Propylamines; D012821:Silanes / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry* / Q000276:immunology; D055672:Static Electricity
chemical_list: D001672:Biocompatible Materials; D007328:Insulin; D008567:Membranes, Artificial; D011437:Propylamines; D012821:Silanes; C021611:aminopropyl silica gel; C088294:3-aminopropyltrimethoxysilane; C061205:tetramethoxysilane; D012822:Silicon Dioxide; D002118:Calcium