Precision Plating of Human Electrogenic Cells on Microelectrodes Enhanced With Precision Electrodeposited Nano-Porous Platinum for Cell-Based Biosensing Applications

Microelectrode Arrays are established platforms for biosensing applications; however, limitations in electrode impedance and cell-electrode coupling still exist. In this paper, the SNR of $25~\mu \text{m}$ diameter gold (Au) microelectrodes was improved by decreasing the impedance with precision electrodeposition. SEM determined that N-P Pt. microelectrodes had nano-porous structures that filled the insulation cylinders. EIS, CV, and RMS noise measurements concluded that the optimized electrodeposition of N-P Pt. led to a lowered impedance of $18.36~\text {k}\Omega \pm 2.6~\text {k}\Omega $ at 1 kHz, a larger double layer capacitance of 73 nF, and lowered RMS noise of $2.08 \pm 0.16~\mu \text{V}$ as compared to the values for Au of $159~\text {k}\Omega \pm 28~\text {k}\Omega $ at 1 kHz, 17nF, and $3.14 \pm 0.42~\mu \text{V}$ , respectively. Human motoneurons and human cardiomyocytes were cultured on N-P Pt. devices to assess their biocompatibility and signal quality. In order to improve the cell-electrode coupling, a precision plating technique was used. Both cell types were electrically active on devices for up to 10 weeks, demonstrated improved SNR, and expected responses to precision chemical and electrical stimulation. The modification of Au microelectrodes with nanomaterials in combination with precision culturing of human cell types provides cost effective, highly sensitive, well coupled and relevant biosensing platforms for medical and pharmaceutical research. [2018-0187]