Abstract

A CMOS-based high-density micro-array sensor is presented to measure electrical impedance of cells, which offers an accurate enumeration and mapping of target cells.

There has been escalating market needs for miniaturized biosensors that measure biological substances accurately and reliably. In parallel, these biosensors are required to provide high sensitivity, high target-specificity, and portability in a low price. Leveraging the recent advances in electronic industry, attention to complementary metal-oxide-semiconductor (CMOS) has been increasing towards biomedical applications [1-4], because CMOS integrated circuits (ICs) integrated with sensing elements can precisely interpret physical/chemical quantities from biological samples to electrical signals in a rapid, versatile, small foot-print and cost-effective way as integrated biosensors.

Here, a highly sensitive label-free CMOS-based high-density micro-array sensor is presented to measure electrical impedance signals from tumor cells, which offers a direct identification and enumeration of target cells, obviating the need of bulky, skill-intensive and expensive optical microscopy. Rapid and automated tumor-cell detection was demonstrated using MCF-7 breast cancer cells, by impedance measurement of the cells on microelectrode array. The electrical impedance spectroscopy (EIS) quantifies loaded cells rapidly (< 2 minutes) in a single cell resolution, with > 95% of mapping accuracy compared to the one obtained from an optical microscope.