Hydrogels for the treatment of spinal cord injury: progress and promise.

Spinal cord injury (SCI) is a devastating condition characterized by complex primary and secondary pathophysiological mechanisms that result in motor, sensory, and autonomic dysfunctions. Despite advances in surgical, pharmacological, and biological therapies, effective treatments remain limited due to the multifactorial nature of SCI and the hostile post-injury microenvironment. In this context, biomaterial-based approaches have emerged as promising platforms, as they can provide both structural support and localized therapeutic delivery. Hydrogel-based systems, in particular, have attracted increasing attention due to their ability to mimic the extracellular matrix, modulate the injury microenvironment, and deliver bioactive molecules or cells in a controlled manner. In particular, combinatorial approaches integrating drugs, growth factors, or cellular components often show enhanced efficacy compared to single-component systems. However, direct comparison across studies is limited by substantial heterogeneity in injury models, outcome measures, and experimental design, as well as by reproducibility challenges associated with complex multi-component constructs. Furthermore, translational progress remains constrained by regulatory classification, manufacturing scalability, and standardization issues. Overall, while hydrogel-based strategies represent a promising platform for SCI repair, future research must prioritize reproducibility, simplification of design, and alignment with regulatory and clinical requirements to enable successful translation.