Ultrasensitive amperometric cytosensor for drug evaluation with monitoring early cell apoptosis based on Cu2O@PtPd nanocomposite as signal amplified label

Abstract

It is significant to monitor the early stage of apoptosis and evaluate the therapeutic effect of anticancer drugs in the diagnostic of cancer. Here, an electrochemical cytosensor with signal amplified strategy was constructed to quantitatively detect the concentration of early apoptotic cells and respond to therapy of anticancer drugs. To fabricate the platform, cuprous oxide (Cu2O) cube was utilized as a large platform for loading platinum-palladium nanoparticles (PtPd NPs) to prepare the Cu2O@PtPd nanocomposites. The formed nanocomposite was not only acted as signal amplified molecules towards the reduction of H2O2 by synergistic effect but also possessed large specific area to conjugate concanavalin A (Con A), which specifically interacted with the cell-surface carbohydrate. What’s more, the porous graphene oxide-Au (PGO-Au) nanocomposites were modified onto working electrode to improve the efficiency of electron transfer. Meanwhile, the PGO-Au nanocomposite was served as effective matrix to couple annexin V through Au-N bond to capture apoptotic cells owing to the specific interaction between phosphatidylserine (PS) on the cell surface and annexin V. In this system, A549 cell was chosen as model cells and cisplatin acted as apoptotic inducer. The proposed amperometric cytosensor exhibited a wide range detection of early apoptotic cells from 50 to 5 × 107 cells mL−1. Meanwhile, the detection limit was down to 20 cells mL−1. It also showed high specificity, acceptable sensitivity and good reproducibility, which had promising potential for the early evaluation of therapeutic effect.