title: Extracellular matrix for a rechargeable cell delivery system.
abstract: Above a critical concentration, aqueous polymer solutions of N-isopropylacrylamide copolymers with small amounts of acrylic acid, synthesized in benzene by radical polymerization, exhibited four distinct phases as the temperature increased; clear solution, opaque solution, gel and shrunken gel. The transition between the opaque solution phase and the gel phase was in the range of 30-34 degrees C and was reversible without syneresis and noticeable hysteresis under the experimental conditions used in this study. Islets of Langerhans, isolated from Sprague-Dawley rat pancreata and entrapped in the gel matrix, remained viable, with no significant decrease in insulin secretion function in vitro for one month. When islets were encapsulated with the gel matrix in hollow fibers [molecular weight cut-off (MWCO)= approximately 400000] and were exposed to dynamic changes in glucose and theophylline concentrations, their insulin secretion patterns demonstrated a smaller lag time and higher amplitude in insulin release than islets entrapped in a conventional alginate matrix under the same experimental conditions. From these two observations, i.e. gel reversibility and islet functionality in the matrix observed in in vitro experiments, the N-isopropylacrylamide copolymers with acrylic acid synthesized in this study are optimum candidates for the extracellular matrix in a diffusion chamber-type cell delivery system in order to recharge the entrapped cells when cell functionality in the system decreases.
authors.affiliation: Department of Materials Science and Engineering, Kwangju Institute of Science and Technology, Korea. yhbae@matla.kjist.ac.kr
authors.forename: Y H
authors.initials: YH
authors.lastname: Bae
authors.forename: B
authors.initials: B
authors.lastname: Vernon
authors.forename: C K
authors.initials: CK
authors.lastname: Han
authors.forename: S W
authors.initials: SW
authors.lastname: Kim
mesh_terms: D000178:Acrylamides; D000818:Animals; D005109:Extracellular Matrix; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism; D016381:Islets of Langerhans Transplantation; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000178:Acrylamides; D007328:Insulin; C067295:N-isopropylacrylamide