A dynamic electrochemical cell sensor for selective capture, rapid detection and noninvasive release of tumor cells

Abstract Timely discovery and detection of pathogenic factors (i.e., circulating tumor cells) are of great significance for early diagnosis and therapy of tumorigenesis and metastasis, which gives the emergence of developing a way for rare cell biosensing. In this paper, we reported a dynamic electrochemical biosensor enabling specific capture, rapid detection and noninvasive release of target tumor cells. The biosensor was fabricated by grafting phenylboronic acid (PBA)-containing polymer on ITO-glass following with reversible immobilization of tumor cell targeting molecules via sugar-responsive PBA-catechol dynamic covalent chemistry. We found that the dynamic electrochemical biosensor showed a nice linear relationship between the captured cell densities and impedances (or currents) by EIS (or DPV) methods. Moreover, a high detection sensitivity with minimum detection limit at 3 cells mm-2 was observed for target tumor cells (for example MCF-7 cells). Further study in a mixture of MCF-7 and HepG 2 cells revealed that, the number of detected MCF-7 cells shown no statistical difference compared to those of fluorescent labelling and counting method. Besides the good selectivity, the sugar-responsive molecular binding on the biosensor enabled noninvasive cell collection with a high viability over 87.2 %. In short, our dynamic electrochemical biosensor represents a promising platform for specific tumor cell detection and monitoring the cell capture and release, which paves the way for future diagnosis of early discovery and detection of tumorigenesis and metastasis.