Sensitive detection of tumor cells by a new cytosensor with 3D-MWCNTs array based on vicinal-dithiol-containing proteins (VDPs)

Vicinal-dithiol-containing Proteins (VDPs) are overexpressed in cancer cells and become a potential biomarker for aggressive tumors, the synthesized 2-p-aminophenyl-1, 3, 2-dithiarsenolane (VTA2) is proved to be a highly selective ligand for vicinal dithiols of VDPs in cells. In this report, we developed a new cytosensor based on three-dimensional (3D)-like VTA2-conjugated multiwalled carbon nanotubes (VTA2@MWCNTs) array modified indium tin oxide (ITO) electrode for sensitive and selective detection of VDPs-overexpression tumor cells. The layer-by-layer assembling and cellular detection performances of the 3D-VTA2@MWCNTs-based cytosensor were investigated by atomic force microscopy (AFM) and electrochemical methods including cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). Attributed to signal amplification and targeting recognition of the 3D-structured MWCNTs@VTA2, the fabricated cytosensor showed high specificity and sensitivity to the detection of VDPs-overexpression HL-60 cells ranging from 2.7 x 10(2) to 2.7 x 10(7) cells mL(-1) with a low detection limit of ca. 90 cells mL(-1). Furthermore, the captured cancer cells on the cytosensor also could be directly visualized by optical microscopy technology. This proposed 3D-MWCNTs array-based cytosensing strategy provides a simple, sensitive approach for non-invasive cell detection, presenting potential applications in cancer diagnosis. (C) 2014 Elsevier B.V. All rights reserved.