Cryofixation Strategy for Fabrication of Robust Gelatin-Polyester Conductive Biocomposites

Abstract

The development of mechanically robust and electroconductive biomaterials is critical for advancing tissue engineering strategies, particularly in neural, cardiac and musculoskeletal applications. Here, we report a polycaprolactone (PCL)-gelatin conductive polymer (poly(3,4-ethylenedioxythiophene):polystyrene sulfonate, PEDOT:PSS) biocomposite with tunable mechanical and electrical properties, fabricated via the cryofixation process relying on rapid reaction between isocyanate-terminated PCL, gelatin and PEDOT:PSS. Two isocyanate sources, hexamethylene diisocyanate (HDI) or isophorone diisocyanate (IPDI) were employed to obtain reactive end-functionalized PCLHDI and PCLIPDI. The cryofixation (at -18 degrees C) of PCLHDI or PCLIPDI, gelatin and PEDOT:PSS was found to occur in unfrozen microdomains and enabled the resultant gel with an inherited network of ice, thereby increasing porosity. Electroconductivity was introduced via the incorporation of PEDOT:PSS, yielding conductive cryogels with porous morphology. The resulting scaffolds exhibited a Young's modulus of 637 Pa and electrical conductivity of 197 mu S/cm, alongside biocompatible nature of gelatin-based gels. This multifunctional platform offers significant promise for the engineering of electrically active tissues.