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In Vitro Studies on a New Method for Islet Microencapsulation Using a Thermoreversible Gelation Polymer, N‐Isopropylacrylamide‐Based Copolymer
Author(s) -
Shimizu Shinichi,
Yamazaki Manabu,
Kubota Sunao,
Ozasa Takao,
Moriya Hitonobu,
Kobayashi Kenyu,
Mikami Masato,
Mori Yuichi,
Yamaguchi Susumu
Publication year - 1996
Publication title -
artificial organs
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.684
H-Index - 76
eISSN - 1525-1594
pISSN - 0160-564X
DOI - 10.1111/j.1525-1594.1996.tb00666.x
Subject(s) - islet , polymer , copolymer , agarose , membrane , in vitro , poly(n isopropylacrylamide) , dextran , chemistry , polymer chemistry , transplantation , chemical engineering , materials science , chromatography , insulin , biophysics , biochemistry , organic chemistry , surgery , endocrinology , medicine , biology , engineering
Various materials for the semipermeable mem‐ brane for microencapsulation of islets, such as alginate complex and agarose, have been used. In this study, a thermoreversible gelation polymer, N‐isopropylacrylamide based copolymer was used to make microencapsulated islets and was examined in vitro. The polymer has little or no cytotoxicity for human dermal fibroblasts. The characteristics of viscoelasticity below the soluble gel transition temperature (SGTT) and of thermoreversibility, the water soluble polymer below the SGTT (22 o C) becoming water insoluble upon heating, contributed to simplifying the encapsulation technique. We obtained viable islets at the center of the membrane with a thickness of approximately 20–50 pm, accounting for a 40% yield of encapsulated islets. Static glucose challenge test with mi‐ croencapsulated islets revealed the insulin response to the concentration of glucose. The insulin concentrations of the culture medium in the microencapsulated islet group were the same as those in a similar free islet group up to 42 days. These results indicate that the morpholog‐ ical and functional stability of the new method for mi‐ croencapsulation may be sufficient for it to be used for transplantation in diabetic animals.