A Fully Integrated CMOS Fluorescence Biochip for DNA and RNA Testing

Design and successful implementation of a fully integrated CMOS fluorescence biochip for deoxyribonucleic acid (DNA)/ribonucleic acid (RNA) testing in molecular diagnostics (MDx) is presented. The biochip includes a 32 × 32 array of continuous wave fluorescence detection biosensing elements. Each biosensing element is capable of having unique DNA probe sequences, wavelength-selective multi-dielectric emission filter (OD of 3.6), resistive heater for thermal cycling, and a high performance and programmable photodetector. The dimension of each biosensor is 100 μm × 100 μm with a 50 μm × 50 μm Nwell-Psub photodiode acting as the optical transducer, and a ΣA modulator-based photocurrent sensor. The measured photodetector performance shows ~116 dB detection dynamic range (10 fA-10 nA) over the 25 °C-100 °C temperature range, while being~1 dB away from the fundamental shot-noise limit. To empirically demonstrate the compatibility of this biochip with MDx applications, we have successfully utilized the array and its thermal cycling capability to adopt a 7-plex panel for detection of six human upper respiratory viruses.