Aligned silk fibroin fiber conduits with enhanced capability for guiding peripheral nerve repair

Nerve guide conduits (NGCs) offer promise for peripheral nerve regeneration, yet their performance remains inferior to autologous nerve grafts. To address this limitation, we developed novel aligned silk fibroin nerve conduits (ASNC) and evaluated their performance in enhancing nerve regeneration. ASNCs were fabricated and their biocompatibility and regenerative potential were assessed in vitro and in vivo. Random silk fibroin nerve conduits (RSNCs) served as control materials. In vitro experiments evaluated ASNC effects on cell adhesion, proliferation, and morphological elongation. For in vivo studies, a 10-mm-long sciatic nerve defect rat model was established, followed by ASNCs treatment. Post-implantation evaluations included axonal regeneration (sciatic function index, myelinated fiber density, muscle weight preservation) and functional recovery (walking track analysis, electrophysiology, histological evaluations). Compared to RSNCs, ASNCs significantly promoted cell adhesion and directional growth along the aligned fibers, whereas RSNCs exhibited slower growth and random orientation. In vivo results showed ASNCs achieved axonal regeneration and functional recovery comparable to autografts. This was demonstrated by improvements in the number and area of myelinated nerve fibers and enhanced muscle wet weight ratios. The newly developed ASNCs demonstrated comparable effectiveness to autografts in guiding axonal growth and promoting nerve regeneration. These findings position ASNCs as a promising alternative to autologous nerve grafts, offering a viable therapeutic approach for peripheral nerve repair. This study demonstrates that aligned silk fibroin nerve conduits (ASNCs) significantly enhance peripheral nerve regeneration, achieving functional recovery comparable to autologous nerve grafts. By leveraging the directional guidance of aligned fibers, ASNCs promote axonal growth and mitigate the limitations of current treatments, such as donor site morbidity and insufficient donor tissue availability. These findings advance the field of neural tissue engineering by providing a scalable, biomaterial-based alternative for peripheral nerve repair. The potential clinical translation of ASNCs offers a promising therapeutic strategy for addressing long-gap nerve defects, with implications for improving patient outcomes and expanding treatment options.