Modular bioreactor for multi-well electrical stimulation of in vitro cardiac tissue engineering constructs

Systems for providing electrical stimulation to in vitro cell cultures are valuable in many tissue engineering applications. We designed and fabricated a novel modular bioreactor consisting of a printed circuit board assembly and carbon paper electrodes which is compatible with commercially available 12-well plates. Our system is the first low-cost, accessible bioreactor of its kind and capable of simultaneously supplying four different amplitudes of stimulus waveform to different wells of the bioreactor. SPICE and FEA were used to model and validate the delivery of these stimuli to cells in culture. We then used our bioreactor to apply 0 V, 0.1 V, 1 V, and 10 V of electrical stimulation to neonatal rat cardiomyocytes (NRCMs), with and without neonatal rat ventricular fibroblast co-culture, for 10 minutes daily on 7 consecutive days. Electrically stimulated NRCMs maintained viability except in response to 10 V stimulation in the absence of fibroblast co-culture. Furthermore, NRCMs exposed to 0.1 V stimulation exhibited enhanced markers (sarcomeric α-actinin and connexin 43) and upregulated genes (βMYC, cTnI, Cav1, and Cx43) related to cardiac electrophysiology compared to non-stimulated controls. This suggests 0.1 V stimulation with our bioreactor is advantageous for the electrophysiological function of primary cardiac cells; it may also be useful in electrophysiologically maturing induced pluripotent stem cell-derived cardiomyocytes.