Quantitative detection system for immunostrips in 180nm standard CMOS technology

Abstract

In this work, a CMOS based optical read-out system for biomarker on immunostrips detection is presented. For the proposed system, a CMOS integrated circuit containing an on-chip photodiode is designed in standard 180 nm UMC CMOS Technology. The system also contains cost-effective 3D Printed structures for holding both IC and the sample immunostrip together. The proposed system can be operated in two modes (1) light reflectance and (2) light transmittance. In the system, a laser with a wavelength of 637 nm is applied to the CMOS IC through immunostrip. Photovoltaic and photoconductive measurements are carried out for each mode on a custom Gluten biomarker immunostrip. Sensing operation of the biomarker is successfully realized with optical powers from 5 mW to 8 mW. Biomaterial density on the immunostrip is sensed and images of the biomarker with varying intensities are constructed from the measurements. Feasibility of the system for low power biomarker sensing applications is demonstrated.