Macroporous hydrogel membranes for a hybrid artificial pancreas. I. Synthesis and chamber fabrication

Abstract

We report development of special macroporous semipermeable membranes and diffusion chambers made of polymerized 2-hydroxyethyl methacrylate (pHEMA), synthesized specifically to enclose living insulin-producing pancreatic islet cells for the treatment of diabetes. This material was selected to minimize the fibrotic encapsulation which has limited hybrid artificial pancreas efforts with other membranes, including Millipore and Nuclepore filters. The pore density and pore size distribution were dependent on the ratio of water to HEMA monomer and also on the crosslinker (EGDMA) concentration. A macroporous membrane resulted only when the ratio of water/HEMA monomer was greater than 50%. 125I-insulin permeability was studied in vitro. A technique is also described to fuse the membranes to form diffusion chambers used for implantation into diabetic rats.

Effect of water content on transparency, swelling, lidocaine diffusion in p-HEMA gels

“…5c and d due to the higher concentration of excess water in the structure compared to the 50% gel. These results agree with the studies of Ronel et al [42] in which they observed no pores for WCIPM below 50% and observed pores 5-10 m is size for WCIPM of 60%.…”

“…[34]. There are also a number of studies in literature that have focused on studying the effect of water content on the polymerizing mixture on the material properties of p-HEMA hydrogels [35][36][37][38][39][40][41][42]. Also a large number of studies have focused on understanding and modeling release of solutes from hydrogels.…”

Liquid–liquid two-phase systems for the production of porous hydrogels and hydrogel microspheres for biomedical applications: A tutorial review

“…In 1983, macroporous HEMA membranes were used to form containers for the transplantation of pancreas tissue [78]. The goal was to enhance the transport of insulin while preventing ingrowth of leucocytes.…”

Eco-, geno- and human toxicology of bio-active nanoparticles for biomedical applications

“…Therefore, also the polymer PDMAEMA was evaluated as an alternative polymer for gene delivery. This methacrylate polymer has excellent biocompatibility and is therefore an interesting alternative for biomedical purposes (Klomp et al, 1979;Ronel et al, 1983;Yasuda, 1975).…”