Electrically conductive materials can stimulate stem cells through electric shock and thereby contribute to the regulation of cell proliferation and differentiation. Recently, polymer-metal complexes composed of polyaniline and gold nanoparticles have emerged as novel candidates for use in regenerative medicine. By mixing two different materials, such composites maximize the benefits while alleviating the disadvantages of using either material alone. Based on their excellent conductivity, these complexes can be applied to nerve regeneration using stem cells. In this study, we investigated a method for producing hybrid nanocomposites by complexing gold nanoparticles to polyaniline and tested the resultant composites in a model of nerve regeneration. We manipulated the shape, size, and electrical conductivity of the hybrid composites by compounding the component materials at various ratios. The most efficient nanocomposite was named conductive reinforced nanocomposites (CRNc's). When the CRNc was delivered directly to cells, no cytotoxicity was observed. After the intracellular delivery of the CRNc, the stem cells were electrically stimulated using an electroporator. As a result of performing mRNA-sequencing (Seq) analysis after electrical stimulation (ES) of the CRNc-internalized cells, it was confirmed that the CRNc-internalized cells have a pattern similar to that of the positive group-induced neuron cells. In particular, microtubule-associated protein 2 is more than twice that of the control group (negative control), and the nerve fiber protein is strongly expressed as in the positive control group. In addition, we verified that neural differentiation progressed by monitoring the growth of neurites from stem cells. Together, these findings show that the CRNc can be used to induce the formation of neuron-like cells by applying ES to stem cells.
Keywords: electrical stimulation; gold nanoparticles (gold NPs); human mesenchymal stem cell; neuron-like cells; polyaniline (PANI).