A CMOS-Based Capacitive Biosensor for Detection of a Breast Cancer MicroRNA Biomarker

Breast cancer ranks among the most common cancers worldwide and can be lethal when not diagnosed early due to the high probability of metastasis. Herein a complementary metal-oxide-semiconductor (CMOS)-based capacitive nano-biosensor was developed to quickly and accurately quantify the concentration of an early-stage breast cancer diagnostic marker, microRNA-195, in blood. The microRNA probe was immobilized on optimized inter-digitated electrodes (IDE), and CMOS-sensing circuits detected the probe-analyte reaction at microRNA-195 concentrations as low as 0.617 fM. This high sensitivity could be due to the monolithically integrated nature of the circuits, for which “parasitic” effects on the capacitive sensors were markedly low. The CMOS-based capacitive nano-sensor may be promising for early diagnosis of breast cancer.