Renewable photoelectrochemical cytosensing platform for rapid capture and detection of circulating tumor cells

Determination of circulating tumor cells (CTCs) is crucial for cancer diagnosis and therapy at an early stage. However, extremely low concentration of CTCs in peripheral blood makes the detection of CTCs challenging. In this study, a reusable cytosensor was developed for rapid detection of CTCs based on excellent photoelectrochemical (PEC) characteristic of semiconductor nanoarrays. Using typical breast cancer cell, MCF-7 cell, as a target model, a PEC sensing platform was constructed with polymerized aminophenylboronic acid (APBA) layer coated CdS/ZnO nanorod arrays, exhibiting outstanding performance for the capture and detection of CTCs. In this design, the polymerized APBA provides abundant binding sites for capturing terminal sialic acid (SA) molecules in CTCs. As a result, the PEC cytosensor shows good sensitivity and specificity with concentrations ranging from 50 to 1.0 × 10⁶ cells/mL MCF-7 cells. Moreover, the PEC cytosensor can be rapidly and effectively recovered via a short-time bias triggered cell release and subsequent repair of APBA. This study establishes a new approach to refine a PEC cytosensor for stable monitoring and provides a robust PEC electrode with high sensitivity and low cost for clinical diagnosis related to CTCs.