Fabrication and characterization of gelatin/carbon black–based scaffolds for neural tissue engineering applications

Neural tissue engineering has recently emerged as an alternative strategy to repair nerve damage and promote nerve regeneration. It involves the fabrication of scaffolds with properties mimicking those of the natural extracellular matrix for guiding a three-dimensional (3D) neural regeneration. These engineered constructs, in addition to mechanical support, should be also capable of providing proper chemical and electrical stimuli for adhesion, migration, and proliferation of the neural cells. In this study, we developed conductive composite hydrogel films based on gelatin and carbon black (CB) as scaffolds for neural tissue engineering applications. The presented hydrogel constructs were fabricated in the form of films using the solvent casting method after dispersing several concentrations of CB in a 5 % (w/v) gelatin solution along with (3-glycidoxypropyl) trimethoxysilane (GPTMS) as the crosslinking agent at a concentration of 1.84 % (v/v). The CB concentrations of 0.3 %, 0.5 %, 0.7 %, and 0.9 % (w/w) with respect to the gelatin amount were chosen. The morphological, compositional, swelling, dissolution, electrical, mechanical, and wettability properties together were characterized as function of CB content and compared with those of pure gelatin-based hydrogel. Results demonstrated that the incorporation of different quantities of CB relatively reduced the water uptake capability of the films and increased the stability in water of the gelatin matrix. Findings from the mechanical tests revealed that composite hydrogels have a lower elastic modulus with respect to the pure gelatin matrix. Moreover, it was found that the incorporation of incremental CB concentrations kept the wettability surface property unchanged while the electrical characterization of the proposed structures showed a reduction of the electrical impedance. Overall, the study suggests that the composite structures could be used as a potential candidate for fabrication of scaffolds for neural regeneration with tunable electrical and mechanical properties by varying the CB concentration in a finite range.