A 69μW Dual-Mode Electrochemical miR-21 Detection SoC with 3^rd-Harmonic Direct-Solution Technique

MicroRNA-21 (miR-21) serves as an early biomarker for multiple diseases, including multiple tumors [1] and central nervous system disorders. The electrochemical miR-21 detector acts as a critical regulator of diverse cellular processes, such as cell differentiation, proliferation, invasion, apoptosis, and metabolism. However, the massive and frequent detections during epidemics have challenged miR-21 detection in device cost and testing time. There are two design challenges in conventional biomarker detection circuits (Fig. 1, top left & middle): 1) The sinusoidal stimulation source in electrochemical impedance spectroscopy (EIS) mode dominates the system power consumption, limiting the lifetime in long-term massive detections. 2) The frequency sweeping procedure in EIS takes a long time in the detection of a large amount of samples.