Electrochemical self-signal identification of circulating tumor DNA based on poly-xanthurenic acid assembled on black phosphorus nanosheets

Abstract

Abstract A self-signal electrochemical identification interface was prepared for the determination of circulating tumor DNA (ctDNA) in peripheral blood based on poly-xanthurenic acid (PXTA) assembled on black phosphorus nanosheets (BPNSs) acquired through simple ultrasonication method. The electropolymerization efficiency was promoted due to the physical adsorption between the xanthurenic acid (XTA) monomers and BPNSs, which was beneficial to the enlargement of the signal response of PXTA. The assembled PXTA/BPNSs nanocomposite with attractive electrochemical activity was adopted as a platform for the recognition of DNA immobilization and hybridization. The probe ssDNA was covalently fixed onto the PXTA/BPNSs nanocomposite with plentiful carboxyl groups through the terminate free amines of DNA probes by use of the 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-hydrosulfosuccinimide cross-linking reaction, accompanied with the decline of the self-signal response. When the hybridization between the probe ssDNA and the target DNA was accomplished, the self-signal response of the nanocomposite interface reproduced by virtue of the shaping of helix construction. The determination limit of the assembled DNA identification interface was 2.1×10− 19 mol/L, and the complementary target DNA concentrations varied from 1.0×10− 18 mol/L to 1.0×10− 12 mol/L. The DNA identification platform displayed magnificent sensitivity, specificity and stability, and was efficaciously implemented to the mensuration of ctDNA derived from colorectal cancer.