CMOS Image Sensor for Lateral Flow Immunoassay Readers

Point-of-care systems for the detection of infectious diseases are in great demand especially in developing countries. Lateral flow immunoassays are considered ideal biosensors for point-of-care 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 per second 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.