Neuroprotective Nanomaterials for Central Nervous System Injury: Beyond Drug Delivery Toward Functional Neurorepair

Neurological disorders and central nervous system (CNS) injuries, including neurodegenerative diseases, ischemic stroke, and traumatic brain injury, represent a major cause of disability worldwide. Despite their diverse etiologies, these conditions share common pathological mechanisms, including oxidative stress, neuroinflammation, mitochondrial dysfunction, excitotoxicity, and impaired regenerative capacity, which collectively contribute to progressive neuronal loss and limited functional recovery. Although nanotechnology has traditionally been investigated as a strategy to improve drug delivery to the CNS, growing evidence indicates that many nanomaterials possess intrinsic biological activities that extend beyond their role as passive carriers. In this review, we summarize the principal classes of neuroprotective nanomaterials and discuss the molecular and cellular mechanisms through which they modulate oxidative stress, inflammation, apoptosis, neurogenesis, synaptic plasticity, and tissue regeneration. We further examine their applications in neurodegenerative diseases, ischemic stroke, traumatic brain injury, and peripheral nerve injury, highlighting their emerging role in bridging neuroprotection and neurorepair. Importantly, we propose a conceptual shift from the conventional material-based classification of nanomaterials toward a function-based framework that categorizes nanotherapeutics according to their predominant biological activities, including antioxidant, anti-inflammatory, anti-apoptotic, neurogenic, synaptogenic/neuroplastic, regenerative, and multifunctional effects. Finally, we discuss the major challenges associated with clinical translation and future perspectives for the development of next-generation nanotherapeutics. This function-based perspective may provide a useful framework for guiding the rational design of innovative strategies aimed at promoting functional recovery following CNS injury.