Development of Nanostructured Electrode Interfaces to Direct Neurogenesis in Neurospheres

Neurodegenerative diseases, including dementia and motor disorders, involve irreversible neuronal loss driven by degeneration, reduced neurogenesis, and chronic neuroinflammation, leading to cognitive and functional decline. Neural stem cells (NSCs) offer promise for regenerative therapy due to their ability to self-renew, differentiate into neural lineages, and secrete neuroprotective factors. However, therapeutic use is limited by challenges in controlling their migration, differentiation, and integration into neural circuits. Electrical stimulation (E-stim) has emerged as a promising method to modulate NSC behavior, promoting migration, differentiation, and survival in a voltage-dependent manner. This study investigated the effects of biphasic E-stim on adult hippocampal progenitor cells (AHPCs) cultured as neurospheres on smooth and nanopatterned gold electrodes embedded in a chip. Cells were stimulated at 20 or 40 mV (1 Hz, 10 min/day) for 5 days in vitro. Results showed high cell viability (>98%) on all electrodes. Electrical stimulation at 20 mV significantly enhanced neuronal differentiation, indicated by increased TuJ1 expression, whereas 40 mV showed no benefit and sometimes inhibited neurogenesis. In nonstimulated conditions, the mature neuron marker MAP2ab was more prominent. The oligodendrocyte marker RIP was highest on unstimulated nanopatterned surfaces, and the astrocyte marker GFAP was minimal across all conditions. These findings support using gold substrates combined with electrical stimulation as a viable strategy for neural regeneration.