Highly Sensitive Photoelectrochemical Sensing Platform Based on PM6:Y6 P-N Heterojunction for Detection of MCF-7 Cells

Development of novel photoactive materials is of great significance for improving the analytical performance of photoelectrochemical (PEC) biosensors. Herein, sensitive PEC biosensor was developed based on organic PM6:Y6 p-n heterojunction as photoactive matrix for circulating tumor cells (CTCs) detection. Y6, as organic acceptor that combines with the organic donor PM6 forms p-n heterojunction promoted separation of photo-generated charges with high charge transfer efficiency, resulting in the enhancement of photocurrent intensity. The detection of CTCs was achieved through the traditional "sandwich" protocol. Magnetic nanobeads (MNs) decorated with anti-epithelial cell attachment molecule antibody (anti-EpCAM) were used for capturing and separating CTCs, while the Au-aptamer probe and silver staining reaction were designed for dual signal amplification. The localized surface plasmon resonance (LSPR) of gold nanoparticles (Au NPs), and silver nanoparticles (Ag NPs) that generated by silver staining reaction improved photocurrent response of PEC sensor. This PEC biosensor was applied to detect MCF-7 and displayed an ultra-low detection limit of 9 cell mL-1 and linear range from 10 to 10000 cell mL-1. This work explored a path for the application of organic semiconductors as photoactive materials in PEC sensing, which may find broad applications for detecting varied analytes.