Polydopamine Functionalization of Aligned Polylactic Acid Microfibers for Enhanced Neural Cell Interaction and Oxidative Stress Mitigation

Abstract Peripheral nerve injuries (PNIs) result in severe functional impairments and pose a significant clinical and socio-economic burden. Although autologous nerve grafts remain the clinical gold standard, their use is limited by donor availability and associated morbidity. Biomaterial-based strategies incorporating aligned architectures have emerged as promising approaches to provide directional guidance for regenerating axons. However, synthetic polymers commonly used for these systems lack intrinsic bioactivity and offer limited protection against the oxidative microenvironment present after injury. Here, aligned polylactic acid (PLA) microfibers were functionalized with polydopamine (PDA) via a one-step immersion process to introduce bioactive and antioxidant surface properties. The PDA-coated microfibers were systematically characterized in terms of morphology, surface chemistry, roughness, antioxidant capacity, and hydrogen peroxide scavenging. In vitro assays demonstrated that PDA functionalization enhanced Schwann cell attachment and improved cellular tolerance to hydrogen peroxide-induced oxidative stress, while also enhancing dorsal root ganglion adhesion and neurite outgrowth along the microfiber axis. Overall, these results indicate that PDA functionalization enhances the biological performance of aligned PLA microfibers by integrating structural guidance with oxidative stress modulation, highlighting their potential as versatile guidance elements for future nerve repair applications.