Posted by Joe Foregger on October 10, 1997 at 23:00:03:
I came across an interesting magizine article from "Trends in Polymer Science" entitled 'Polymers for Bioartifical Organs' by David Hunkeler.(Located at the Laboratory of Polymers and Biomaterials, Dept. of Chemistry, Swiss Federal Institute of Lusanne. Sept. 97 Issue Vol 5 No. 9 Pg. 286-293
The abstract is as follows:
A review of polymers for the formation of permselective capsular membranes is presented. In particular, the immunoisolaton of pancreatic islets for production of a bioartificial pancreas is evaluated. A screening of polyelectrolytes with respect to cell cytotoxicity is discussed, together with an evaluation or polymer-structure-biomaterial function relationship. A summary of the various polymer chemistries, mechanisms of membrane formation and microencapsulation technologies is presented and a categorization proposed. Four cases are compared in detail: Sun's algimate-calcium-chloride based precast beads, binary poly anion-polycation coacervation systems, multicomponent polyelectrolyte capsules with gel precasting and oligocation diffusion to control the cut-off, and Sefton's phase-inversion systems based on non-ionic, elastic, hydrophobic copolymners'
The article is quite technical but has some interesting graphs and a glossry of terms.
The atricles concluding remarks are:
'It is premature to pass judgement on the efficacy of various polymer chemisties(Types I-VI), mechanisms of membrane formation(types A-G), or encapulation technologies(types alpha-gamma) Each system, as well as the four specific combinations reviewed here, has advantages and limitations. It is encouraging that, at this preclinical stage, alternatives exist, because it is unlikely that one given chemistry, for example, will be suitable for all juvenile-onset diabetics, or even of a given person over the typical 40-50 year duration of the disease. Furthermore, most medical treatments present alternatives, with respect either to chemical composition or to size, to prescribing physician or surgeon. It seems reasonabe to expect a similar diversity from a family of bioartifical pancreas based on research in polymers, engineerig and medicine.'
The articles is about 8 pages and gives a good idea of the limitations of some polymer systems.