Soft Scaffolds for Nerve Repair: Investigating Glycerol-Plasticized Chitosan Microstructures With In Vitro Complex Models

Peripheral nerve injuries are a significant clinical concern, often resulting in incomplete functional recovery due to the limitations of current treatments. Biomaterial-based scaffolds that mimic the mechanical and topographical features of native nerve tissue represent a promising strategy to support regeneration. In this study, we investigate the regenerative potential of soft and nerve-mechanically compliant glycerol-plasticized chitosan (Gly-chi) microstructured membranes with in vitro models with increasing biological complexity. These soft directional microgrooved membranes promoted invasion, polarization, and alignment of primary Schwann cells (SCs), and further promoted neurite outgrowth and directional guidance of human iPSC-derived sensory neurons when co-cultured on SCs. Moreover, tests with rat dorsal root ganglia (DRG) explants confirmed the ability of these scaffolds to orient axonal extension also in an ex vivo setting. Interestingly, neurites aligned even over a confluent SC layer, indicating that topographical cues may be transmitted via SC-mediated signaling in addition to direct contact. Overall, our findings demonstrate that glycerol-blended chitosan membranes with a physiological-grade stiffness, similar in respect to nerve tissues, and micro-structured with directional grooves effectively support both glial and neuronal organization and represent a robust biomimetic platform for peripheral nerve repair and advanced in vitro modeling applications.