CMOS Image Sensor for Lateral Flow Immunoassay Readers

Point-of-care (POC) systems for the detection of infectious diseases are in great demand especially in developing countries. Lateral flow immunoassays are considered ideal biosensors for POC diagnostics due to their numerous advantages. However, to quantify their results a low power, robust electronic reader is needed. A low power CMOS image sensor is presented that can be used in quantitative lateral flow immunoassay readers. It uses a single low power processing capacitive transimpedance amplifier architecture which includes noise cancellation. A chip containing 4 × 64 pixels was fabricated in CMOS 0.35-μm technology. With uniform illumination at 525 nm and 67 frames/s the chip has 1.9 mVrms total output referred noise and a total power consumption of 21 μW. In tests with lateral flow immunoassays the chip detected concentrations of influenza A nucleoprotein from 0.5 ng/mL to 200 ng/mL.