Thiolated Chitosan-Stearic Acid Thiol-Linked Biomimetic Hydrogels for Axonal Regrowth and Neuronal Tissue...

Neuronal disorders like spinal cord injury, stroke, peripheral neuropathy, and neurodegenerative diseases like Alzheimer's disease, Parkinson's disease, etc., need regenerative approaches and therapeutics like tissue engineering and cell therapy for neuronal systems. Significant factors such as neuronal damage, impaired immune response, and glial scar formation create a hostile environment for neural repair and functional recovery. To overcome these challenges, the development of biocompatible and bioactive biomaterials is essential for therapeutic applications. In this work, a thiolated chitosan-stearic acid (Tch-Sa) hydrogel was prepared by modifying chitosan and stearic acid with free thiol (SH) groups, mimicking the high lipid content and GaGs in neuronal tissue. The hydrogel was crosslinked via disulfide linkages. The hydrogels were characterized using FTIR, ¹H NMR, Raman spectroscopy, and TGA. Rheological evaluation demonstrated stable mechanical behavior, with storage and loss moduli showing structural consistency. In vitro cytocompatibility studies with N2a neuronal cells showed good adhesion, proliferation, and gradual morphological development. By day 7, cells displayed extended axonal projections. Immunofluorescence staining revealed increased expression of neuronal proteins, supporting the hydrogel's role in promoting neuronal differentiation and maturation. Moreover, the introduction of thiol groups enhanced cell permeability, mucoadhesive properties, and axonal outgrowth, suggesting that this material may be helpful in neuronal tissue engineering applications.