Electrochemical and optical CMOS sensors design for biochemical detection

Abstract

Population ageing has driven the incremental demands on portable and cost-efficient point-of-care diagnostics. However, most of the existing techniques require bulky and expensive high-end instruments. New methods based on CMOS sensors are possible solutions.

In this thesis, three types of CMOS sensors are studied for biochemical detection: CMOS ion-sensitive field-effect transistor (ISFET) sensor for food safety screening, CMOS chronocoulometric sensor for the heavy metal monitor, and CMOS fluorescence sensor for near-infrared quantum dots detection. In-depth understanding of these novel CMOS sensors is presented here from working principles, circuit designs, to the experimental results. Sub-threshold amplifier and capacitive transimpedance amplifier (CTIA) are proposed to realize a high-sensitivity detection. Correlated double sampling (CDS) and pixel calibration are employed to reduce the variations in an array.

The demonstrated CMOS biosensors are low-cost and miniaturized. They could become promising in personalized biomedical tests in future.