A One-Step-Packaged CMOS/Microfluidics Wireless Bio-Analyzer for Point-of-Care Diagnostics

Point-of-care (POC) diagnostics can revolutionize current medicine by enabling rapid, at-home molecular testing for early disease detection and treatment monitoring. Though several mainstream POC technologies exist, such as paper-based lateral flow assays (LFAs) and microfluidic cartridges, they either lack quantification capability or require a dedicated reader for electrical readout. Miniaturization enabled by high-performance CMOS integrated circuits (ICs) has been proposed to address these limitations, but complex CMOS/microfluidics packaging due to the need for electrical connections remains a significant challenge. In this work, we present a fully wireless solution based on near-field inductive coupling. By enabling wireless power and data communication through a 1.5-mm on-chip coil operating at 700 MHz, the CMOS chip can be seamlessly embedded into standard microfluidics fabrication flows. The proposed CMOS bio-analyzer supports electrochemical, pH, and temperature sensing. The electrochemical front end performs highly sensitive readout from immunosensors, while the pH and temperature sensors are used to mitigate environmental effects. Implemented in TSMC 180-nm CMOS technology, the system consumes 2 mA from a rectified 2.5-V supply. The electrochemical sensor employs a fully differential capacitive transimpedance amplifier (TIA) and achieves 0.24-pA<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rms</sub> input-referred current noise and 128.8 dB of extended dynamic range. Immunosensing of C-reactive protein (CRP) and a prototype vacuum-driven microfluidics device are demonstrated.