LC-Voltage-Controlled-Oscillator-Based Biosensor in 180-nm CMOS Process Targeting β-Dispersion for Detecting Exosomes

Recently, minimally invasive cancer care represented by liquid biopsy has attracted considerable interest. Some substances in blood, such as circulating tumor cells and exosomes, are receiving increasing attention as potential biomarkers for liquid biopsy. In this paper, we present an LC-voltage-controlled-oscillator-based biosensor for detecting exosomes. In order to detect exosomes, we focused on dielectric β-dispersion and utilized the frequency band in which β-dispersion occurs. To validate the operation of the proposed system, we performed electromagnetic (EM) analysis. The results of EM simulation demonstrated the possibility of detecting exosomes. In addition, a test chip was fabricated in 180-nm CMOS process. We performed the test chip measurement by adding a drop of water on the inductor, and an average measured frequency shift of 5.723 kHz was confirmed, which demonstrates the feasibility of the proposed biosensor in detecting exosomes.