Integrated Electrostimulation Cell Culture Systems Driven by Chemically Modified Twistron Mechanical Energy Harvesting Electrodes

Developing mechanical energy harvesters for electrical stimulation (ES) needed to augment cell behavior is a burgeoning area of interest. Mechanical energy harvesters that can generate electrical energy in electrolyte-containing aqueous environments offer a unique solution for delivering ES to cells. In this work, a fully integrated ES assembly (FESA) is introduced that comprises coiled polydopamine (PDA) containing carbon nanotube yarn (CNT) harvesters, serving as ES generators, and poly(3,4-ethylenedioxythiophene) coated carbon nanotube (PEDOT/CNT) sheets employed as a conductive scaffold. The PDA containing CNT (PDA/CNT) yarn, a novel twistron electrode, achieves an enhanced electrical power at a lower matching impedance than coiled CNT yarn to efficiently transfer ES to the conductive scaffold. The PEDOT used for the scaffold provides a suitable surface for cell adhesion and low resistance for effective ES transmission. In addition, the upscaled array of coiled PDA/CNT yarns provides an ES current density range up to 75.4 µA cm⁻², which is much higher than for ES systems using different mechanical energy harvesters. This FESA is designed to provide an optimal level of ES for the proliferation and differentiation of chondrocytes. The findings illuminate the potential of chemically modified twistron energy harvesters as an innovative and effective strategy to promote biological response.