Biocompatibility of microstructured polymer materials with potential use in reconstructive surgery

Reconstruction of peripheral nerves remains an urgent surgical problem. Autologous nerve grafting is the gold standard for bridging nerve defects, but it is limited by the shortage of donor material, which drives interest in biocompatible polymers for artificial conduits. The aim of this study was to evaluate biocompatibility in vitro and tissue response to subcutaneous in vivo implantation of perspective microstructured materials. The cytotoxicity of porous polycaprolactone (PCL), PCL–collagen composite, fibrous PCL, and nanofibrous polyamide was assessed on L929 fibroblasts. For in vivo testing, material samples were implanted into C57BL/6 mice, and histological analysis was performed after 14 days. In vitro porous PCL exhibited the highest viability and adhesion, while fibrous PCL showed the lowest. In vivo porous PCL and nanofibrous polyamide caused minimal inflammation, whereas PCL–collagen composite and fibrous PCL induced granulomatous inflammation, macrophage infiltration, and formation of fibrous capsule. The most biocompatible materials — porous PCL and nanofibrous polyamide — show promise for a biomimetic conduit with an outer barrier shell of porous PCL and an inner aligned scaffold of polyamide nanofibers.