NOVEL DESIGNED POLYISOBUTYLENE-BASED BIOPOLYMERS - SYNTHESIS, CHARACTERIZATION, AND BIOLOGICAL TESTING OF AMPHIPHILIC CHAMELEON NETWORKS

After a very brief introduction into the impact of living polymerization on preparative polymer chemistry and a look into the dearth of de novo polymer synthesis research for novel biopolymers, this presentation; will focus on a new class of synthetic biopolymers: amphiphilic chameleon networks, i.e., biocomponent networks comprising random strands of hydrophobic and hydrophilic polymers, for blood contact application and mainly for use as narrow diameter (<4 mm) vascular grafts. First, the precision syntheses of amphiphilic networks will be outlined. Subsequently the surface and bulk characterization of these novel molecular composites by a battery of physicochemical methods will be highlighted. Finally, representative results of biological in-vitro and in-vivo testing will be summarized. We propose that for bio- or hemocompatibility to arise, it may be necessary to employ ''smart'' amphiphilic surfaces capable of rapid reversible hydrophobic/hydrophilic reorganization so as to present the most favorable lowest energy surface conformation to the medium. It appears that these surfaces are smooth, flexible, and of very low modulus, and that the bulk of these materials have cocontinuous phase-separated microarchitectures with random microdomains in the 10-100 Angstrom diameter range. Contemporary macromolecular engineering can deliver materials exhibiting this combination of characteristics.