Sandwich-type electrochemical immunosensor constructed using three-dimensional lamellar stacked CoS@C hollow nanotubes prepared by template-free method to detect carcinoembryonic antigen.

Effective treatment of cancer depends on early detection of tumor markers. In this paper, an effective template-free method was used to prepare CoS@C three-dimensional hollow sheet nanotubes as the matrix of the immunosensor. The unique three-dimensional hybrid hollow tubular nanostructure provides greater contact area and enhanced detection limit. The CoS@C-NH-HRP nanomaterial was synthesized as a marker and had a high specific surface area, which can effectively improve the electrocatalytic ability of hydrogen peroxide (HO) reduction while increasing the amount of capture-fixed carcinoembryonic antigen antibody (anti-CEA). In addition, the co-bonded horseradish peroxidase (HRP) can further promote the redox of HO and amplify the electrical signal. Carcinoembryonic antigen (CEA) was quantified by immediate current response (i-t), and the prepared immunosensor had good analytical performance under optimized conditions. The current signal and the concentration of CEA were linear in the range of 0.001-80 ng/mL, and the detection limit was 0.33 pg/mL (S/N = 3). The designed immunosensor has good selectivity, repeatability and stability, and the detection of human serum samples shows good performance. Furthermore, electrochemical immunosensor has broad application prospects in the clinical diagnosis of CEA.