Biomimetic Glycosaminoglycan Analog Hydrogels Inhibit Neurite Outgrowth While Supporting Neuronal Cell Viability

Intervertebral disc (IVD) degeneration is a leading contributor to chronic low back pain, imposing a substantial global burden. Native IVD tissue relies on sulfated glycosaminoglycans (sGAG) to maintain hydration and mechanical function through fixed negative charges and associated osmotic pressure. With aging, sGAG depletion leads to matrix disorganization, dehydration, and pathological nerve ingrowth—hallmarks of disc degeneration. Synthetic GAG analog hydrogels have recently gained attention as biomimetic candidates for disc repair, owing to their structural resemblance and fixed charge density similarity to native sGAGs. Beyond their biomechanical role, these GAG analogs are hypothesized to act as neuroinhibitory barriers. In this study, we evaluated the neuroinhibitory capability of GAG analogs at varying crosslinking densities (0.5%–2%), using SH-SY5Y neuroblastoma cells. Grown on GAG analogs, neurite extension was markedly suppressed, with average neurite lengths < 10 μm, compared to 79.3 ± 55.8 and 157.1 ± 103.8 μm in control cultures. Importantly, cell viability remained high (75%–92%), irrespective of the presence of exogenous chondroitin sulfate (CS). These findings suggest that, beyond mimicking the mechanical properties of native NP, GAG analogs can also recapitulate the neuroinhibitory roles of native sGAG, underscoring their promise as therapeutic biomaterials for IVD regeneration and the prevention of pain-related nerve infiltration.