Non-enzymatic monitoring of organoid culture media using a microfluidic device with screen-printed electrodes

Electrochemical monitoring of cell culture media holds significant promise for routine evaluation of cell culture conditions, making it invaluable for disease modeling, drug screening, cell therapy, and regenerative medicine. Despite its potential, the application of electrochemical sensing techniques faces challenges, including the requirement for large sample volumes and the complexity of device integration. In this study, we introduce a straightforward method to evaluate the concentration of lactic acid (LA) in culture media using screen-printed electrode (SPE) and a microfluidic device. Standard SPEs were modified via electrochemical reduction of graphene oxide (GO) and deposition of nickel oxide (NiO) nanoparticles within a microfluidic device. Then, they could be used for the LA monitoring on-a-chip over a broad range (0.1–30 mM) with a low detection limit (0.05 mM) as well as the Electrochemical Impedance Spectroscopy (EIS) of the system. The modified SPEs were characterized by Scanning Electron Microscopy (SEM) to show the morphological changes of the electrodes and clarify the mechanism of the quality improvement. Finally, the modified SPEs were used to measure LA concentrations of organoid suspension culture media. Our results showed significant differences in LA concentration, in the media with and without air infusion, proving the effectiveness of the present approach and the usefulness the integrated SPEs for biomedical applications.