Electrochemical Cytosensing Research And Applications Based On Novel Targeted Molecule Materials

The electrochemical biosensing research based on novel targeted molecule materials has showed the broad application prospect in the field of electrochemical catalysis, analytical determination, biomedical sciences and so on. Electrochemical biosensors are provided with a large number of advantages. Such as rapid response, enhanced sensitivity and specificity, apparatus miniaturization etc., developing a new strategy for biological assay with excellent reproducibility, and then improving the electrochemical analysis and the visualization research. Using the targeted molecule materials as the electrochemical sensing platform, it can not only introduce the peculiar property onto the electrode interface but also make the electrode surface equipped with greater specific surface area, higher surface free energy, better biocompatibility and faster electron transfer rate, targeted(fluorescent) probe tracking in time, eventually improving its resulted analytical performance. Electrochemical biosensor plays a critically important role in biomedical applications owing to the combined advantages of high sensitivity, small volume requirements, fast response, low cost, and visualized observation. This paper is devoted to the exploration of biosensing applications in electrochemical cytosensing Research and applications based on novel targeted molecule materials and the main researches are as follows.1. 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 2.7×102 to 2.7×107 cells m L-1 with a low detection limit of ca. 90 cells m L-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. 2. An ultrasensitive sandwich-type electrochemical cytosensor has been initially developed for quantitative determination CD44-overexpressing Hela cells by a maximal signal amplification protocol of 3D-MWCNTs structure construction. HA were first in-site incorporated into the prepared ITO surface to form the HA-MWCNTs@ITO biosensor. Unexpectedly, the so incorporated 3D-MWCNTs structure could dramatically improve the electronic properties and surface chemical reactivity. Herein, HA-MWCNTs@ITO biosensor exhibited a sensitive response to Hela cells compared to HA@ITO biosensor. A sandwiched hybridization protocol was then proposed using BIO as the tracing labels of the fluorescence probes for targeting CD44-positive tumor cells, and the signal amplification was thereby maximized to be measured by the electrochemical outputs by the chronocoulometric methods complementary to the targets. The CD44-positive Hela cells onto the HA immobilized sensing layer led to the decreased CC responses, which changed linearly in the cell concentration range from 2.1×102 to 2.1×107 cells m L-1 with a detection limit of 70 cells m L-1. Such a sandwich-type biosensor may circumvent the bottlenecks of the current detection techniques in detecting and tracing low-level tumor cells. It would be tailored as an ultrasensitive detection candidate toward the diagnosis of cancer and the warning or monitoring of cancer metastasis in the clinical study.