Cryofixation strategy for fabrication of robust gelatin–polyester conductive biocomposites

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 °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 μS/cm, alongside biocompatible nature of gelatin-based gels. This multifunctional platform offers significant promise for the engineering of electrically active tissues.