Characterization And Performance Of Membranes Designed For Macroencapsulation/implantation Of Pancreatic Islet Cells
amphiphilic networks; amphiphilic polymer membranes; Engineering; glucose challenge; macroencapsulation of pancreatic islets; macroencapsulatory membranes; Materials Science; oxygen permeability; polyisobutylene; rat; stars
Amphiphilic polymer membranes were synthesized for macroencapsulation of cells and characterized by select chemical and biological techniques. The membranes were prepared by crosslinking hydrophilic poly(N,N-dimethyl acrylamide) (PDMAAm) main chains with hydrophobic di-, tri-, and octa-methacrylate telechelic polyisobutylene (PIB) stars. The hydrophilic/hydrophobic composition and the molecular weights between crosslink sites (both M-c,M-hydrophilic and M-c,M-hydrophobic) were controlled by synthesis conditions. Small tubular membranes were made by in situ rotational copolymerization/crosslinking and filled with pancreatic rat islets. The water-swelling behavior, mechanical properties, and oxygen and insulin diffusion were studied. Macroencapsulatory performance of these membranes was investigated in vitro by macroencapsulation of pancreatic rat islets within tubular membranes for up to 1.5 months, and studying the insulin secreting ability of encapsulated islets in culture. The membranes are robust and maintain their integrity for the period of encapsulation. They allow oxygen and insulin diffusion. Macroencapsulated islets maintained their viability and insulin secretion over an extended period (i.e., 45 days). (C) 2003 Elsevier Science Ltd. All rights reserved.
Isayeva I S; Kasibhatla B T; Rosenthal K S; Kennedy J P
Biomaterials
2003
2003-09
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1016/s0142-9612(03)00172-8" target="_blank" rel="noreferrer noopener">10.1016/s0142-9612(03)00172-8</a>
Two Generations Of Synthetic Membranes For Biological/medical Applications
amphiphilic membranes; amphiphilic networks; biocompatibility; diffusion; domains; Glucose; immunoisolation; insulin diffusion; isobutylene; living carbocationic polymerization; membranes; polyisobutylene; Polymer Science; polymers; selective permeability; tricomponent
Two generations of amphiphilic membranes synthesized in our laboratories for biologicaUniedical applications are highlighted. Recent results obtained with representative 2nd generation membranes designed specifically for immunoencapsulation of pancreatic islets and cells, are Summarized. The latter tri-component membranes comprise well-defined hydrophilic poly(ethylene glycol) and hydrophobic/oxyphilic polydimethylsiloxane segments crosslinked by oxyphilic polycyclosiloxane domains, which also provide reinforcement. Select membranes are demonstrated to allow the diffusion of glucose and insulin but prevent the permeation of immunoglobulin G. These membranes remain permeable despite long incubation in IgG solution.
Kennedy J P; Rosenthal K S; Kashibhatla B
Designed Monomers and Polymers
2004
2004
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1163/1568555042474112" target="_blank" rel="noreferrer noopener">10.1163/1568555042474112</a>