Enumeration of circulating tumor cells and investigation of cellular responses using aptamer-immobilized AlGaN/GaN high electron mobility transistor sensor array

This study reports the fabrication and characterization of electrical double layer gated AlGaN/GaN High electron mobility (HEMT) biosensor array to capture, detect and count circulating tumor cells (CTCs) of colorectal cancer (CRC). GaN HEMT chips were assembled into a sensor array on a thermo-curable polymer substrate in a simple and robust packaging process. The array had multiple aptamer immobilized sensing sites and was highly sensitive and selective with up to single cell resolution. The present method can detect cells in their native electrolyte composition, in a very short time with extremely low cost compared to the conventional circulating tumor cell assays. The effect of cellular binding in different test environments was further studied and reported. The electrical response of the sensor was discovered to be relevant to the transmembrane potential of the cell. This whole cell sensor array has the potential to be used as a point-of-care diagnostic tool in varied applications such as detection of rare cells, pathogens and studying the dynamics of cellular interactions.