Impact of conduit-filling interactions on the efficacy of fiber and hydrogel fillers in nerve conduits

Nerve conduits offer an alternative to autologous nerve grafts, yet their clinical application remains restricted to short injuries with unsatisfactory outcomes. This study aimed to elucidate the factors responsible for these poor results. We systematically compared three commercially available conduits, assessing their impact on Schwann cells and fibroblasts <i>in vitro</i> alongside their material properties. Additionally, we evaluated the impact of luminal fillings -spider silk, hydrogel, and their combination- on cell behavior. All three hollow nerve conduits inhibited cell attachment, proliferation, and migration. Fillings significantly improved cellular responses, with effects varying depending on conduit type and material. Notably, spider silk and hydrogel influenced each other's efficacy. Our experiments highlight the limitations of empty nerve conduits and served as a mechanistic exploration to unravel the reasons behind the superior outcomes observed with filled nerve conduits, underscoring the imperative for advancements in conduit design.