Anisotropic Injectable Carboxymethyl Chitosan/ Oxidized Alginate Hydrogel Reinforced with Magnetically Aligned Short Fibers for Neural Tissue Engineering

Peripheral nerve injuries remain a major clinical challenge, and current therapeutic options often fail to fully restore nerve function. Injectable polysaccharide-based hydrogels with anisotropic architectures offer significant potential for addressing this issue, owing to their biomimetic features and dynamic network formation via Schiff base crosslinking. Here, an in situ-forming composite hydrogel was developed using carboxymethyl chitosan (CMC) and oxidized alginate (OA) through reversible Schiff base crosslinking to enable injectability and cell-friendly gelation under physiological conditions. Magnetic short fibers (M.SFs) were incorporated within the hydrogel and aligned under an external magnetic field to induce structural anisotropy. The composite hydrogel exhibited a desirable gelation time and tunable viscoelastic features, with aligned fiber group exhibiting higher storage and loss moduli, rather than randomly distributed fibers. Resazurin assay and confocal live/dead imaging demonstrated high cell viability and proliferation of human olfactory ecto-mesenchymal stem cells (OE-MSCs) encapsulated within the composite hydrogels with oriented M.SFs. Furthermore, such anisotropic hydrogels promoted the neural differentiation of OE-MSCs, as confirmed by gene expression with upregulation of β-Tubulin III and GFAP markers via RT-qPCR and Immunohistochemistry analyses. Such hydrogel provides the necessary signals to guide neural cell alignment, making it a promising candidate for neural tissue engineering.