An in situ-gelling conductive hydrogel for potential use in neural tissue engineering.

Cerebral cavitation is usual following acute brain injuries, such as stroke and traumatic brain injuries, as well as after tumor resection. Minimally-invasive implantation of an injectable scaffold in the cavity is a promising approach for potential regeneration of tissue loss. This study aimed to design an in situ gelling conductive hydrogel containing silk fibroin (SF), brain decellularized ECM (dECM), and carbon nanotubes (CNT) for potential use in brain tissue regeneration. 2% w/v SF hydrogels with different concentrations of dECM (0.1, 0.2, or 0.3% w/v) and CNTs (0.05, 0.1, or 0.25% w/v) were fabricated and characterized. It was observed that with the addition of dECM, the porosity decreased, while swelling and electrical conductivity tended to increase. The addition of dECM also led to a faster resorption rate, but no significant change in compressive modulus. Addition of CNTs, on the other hand, led to a denser, stronger, and more regular porous structure, higher swelling ratio, faster gelation time, slower degradation rate, and a significant increase in electrical conductivity. dECM and CNTs combined together resulted in superior porosity, swelling, resorption rate, mechanical properties, and electrical conductivity compared with SF scaffolds containing only dECM or CNTs. Hydrogel samples containing 2% SF, 0.3% dECM, and 0.1% CNTs had a high porosity (58.9%), low swelling ratio (15.9%), high conductivity (2.35×10-4 S/m), and moderate degradation rate (37.3% after 21 days), appropriate for neural tissue engineering applications. Cell evaluation studies also showed that the hydrogel systems support the cell adhesion and growth, with no sign of significant cytotoxicity.