3D carbon nanosphere and gold nanoparticle-based voltammetric cytosensor for cell line A549 and for early diagnosis of non-small cell lung cancer cells

An electrochemical cytosensor for the detection of the non-small-cell lung cancer cell line A549 (NSCLC) had been developed. A microwave-hydrothermal method was employed to prepare monodisperse colloidal carbon nanospheres (CNSs). Gold nanoparticles (AuNPs) were placed on the surface of the colloidal CNSs by self-assembly to obtain 3D-structured microspheres of the type CNS@AuNP. The results of an MTT assay show the microspheres to possess good biocompatibility. The CNS@AuNP nanocomposite was then placed, in a chitosan film, on a glassy carbon electrode (GCE). The voltammetric signals and detection sensitivity are significantly enhanced owing to the synergistic effect of CNSs and AuNPs. A cytosensor was then obtained by immobilization of antibody against the carcinoembryonic antigen (which is a biomarker for NSCLC) on the GCE via crosslinking with glutaraldehyde. Hexacyanoferrate is used as an electrochemical probe, and the typical working voltage is 0.2 V (vs. SCE). If exposed to A549 cells, the differential pulse voltammetric signal decreases in the 4.2 × 10^-1 to 4.2 × 10^-6 cells mL^-1 concentration range, and the detection limit is 14 cells mL^-1 (at S/N = 3). Graphical abstract Schematic presentation of design strategy and fabrication process of the electrochemical cytosensor for A549 cells. (CNS: carbon nanospheres; GA: glutaraldehyde; PEI: polyethyleneimine; AuNPs: gold nanoparticles; BSA: Bovine serum albumin).