Miniaturized Foldable Electrodes with Direct CMOS Integration for Implantable Applications

This study demonstrates the feasibility of directly integrating foldable microelectrodes (starting from $250 \mu \mathrm{~m}$ width and $1600 \mu \mathrm{~m}$ length) with CMOS front-end for implantable biomedical applications. Mechanical robustness was evaluated through Finite Element Method (FEM) simulations and validated by implantation into an agarose phantom, showing no structural failure. Electrical performance was assessed using Electrochemical Impedance Spectroscopy (EIS) measurement, with results in agreement with values reported in the literature, confirming the integrity of the microfabrication process. Additionally, an electrochemical sensing front-end was also designed, consisting of a full-custom digital potentiostat to illustrate functional capability. This study presents a complete and reproducible microfabrication workflow, providing a promising foundation for future development of highly integrated, minimally invasive bioelectronic interfaces.