Effect of carbon nanotubes in electroactive neuron and cardiomyocyte differentiation on conductive 3D printed scaffolds

Carbon nanotubes (CNTs) have shown great potential in tissue engineering applications due to their unique properties, namely by improving electrical and mechanical properties of scaffolds. In recent years the use of 3D patterns, specially honeycomb or hexagonal patterns, to improve cell culture environment has also emerged in the tissue engineering field. Here we design HEMA-PEGDA based 3D printable scaffolds with and without CNTs in order to study the effect of both surface pattern and CNT incorporation on electroactive hiPSC-derived neuron and cardiomyocyte differentiation. Firstly, we tested scaffold biocompatibility with the SH-SY5Y neuroblastoma model, observing great viability and scaffold coverage for the CNT-containing formulation. As for the hiPSC differentiation models, we employed calcium signalling, immunocytochemistry and RT-qPCR techniques for cellular characterization. We found that CNTs and surface topography greatly affect neuronal culture maturation, by improving neuronal marker expression, calcium transient amplitude and axonal network maturation, while cardiomyocyte culture was mainly impacted by CNT presence independently of surface structure, although these conditions were not enough to reach full maturity. Overall, this study provided insights into the impact of surface structure and composition in electroactive cell differentiation and maturation.