Evaluation of asymmetric poly(vinyl alcohol) membranes for use in artificial islets

Center for Biomedical Engineering, College of Medicine, National Taiwan University, Taipei, Taiwan, R.O.C.
Biomaterials (Impact Factor: 8.56). 12/1996; 17(22):2139-2145. DOI: 10.1016/0142-9612(96)00043-9
Source: PubMed
Islets of Langerhans surrounded by a semipermeable membrane to prevent the host immunosystem is a potential way to treat type I diabetes mellitus. In this study, a series of poly (vinyl alcohol) membranes were formed by adding polyethylene glycols to create pores in the skin layer. The permeability study showed the skin layer structure had an influence on the diffusion of low molecular weight glucose, vitamin B12 and insulin. The mass transfer coefficient was improved from 1.04 × 10−4 to 2.16 × 10−4cm/ sec for glucose, from 2.84 × 10−5 to 8.36 × 10−5 cm/sec for vitamin B12 and from 1.45 × 10−6 to 4.15 × 10−6 cm/sec for insulin, whereas the passage of immunoglobulin G was completely prevented, indicating that these membranes could be effective in protecting islets from immunorejection. Thus such a membrane is an alternative potential material for artificial islets. In addition, we examined the insulin secretory response of islets separated by a poly(vinyl alcohol) membrane. We found that the insulinsecretion rate is relatively rapid compared to the permeation rate of insulin; thus, the process of the artificial islets is insulin-diffusion-controlled.

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    • "Amongst them, PVA is the most commonly used polymer for biomedical applications as it is biocompatible, economical and water soluble [24][25][26]. PVA finds its biomedical applications in hemodialysis [27], artificial vitreous [28], contact lenses [29], artificial pancreas [30,31] and implant materials to repair bone [32] and cartilage replacement [33]template to grow from its precursor solutions. In this process, the ionizable OH groups of PVA play an important role as they show affinity towards positively charged calcium ions helping nucleation of HA. "
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    • "There are some studies in the literature dealing with membranes prepared from poly(vinyl alcohol) by the phase-inversion method. Young et al. [12] made a solution of PVA in water and used Na 2 SO 4 /KOH aqueous solution as the coagulation bath. They obtained asymmetric membranes with dense top layers and porous sub layers. "
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    • "The use of synthetic membranes is therefore restricted to cases where the cells are encapsulated after membrane formation (Youngsukkasem et al. 2012). Synthetic membranes can also be constructed into larger devices, with a planar or cylindrical arrangement (Young et al. 1996; Cheryan and Mehaia 1983). In this approach, a large amount of cells is enveloped in large flat-sheet, hollow-fiber, or encased membranes. "
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