Electrochemical Biosensor Employing Bi2S3 Nanocrystals-Modified Electrode for Bladder Cancer Biomarker Detection

Bladder cancer is a kind of malignant tumor with high incidence in the urinary system, complex pathogenic causes, and the high recurrence rate. Biosensors capable of rapid, on site, and accurate bladder cancer diagnosis method continue to be lacking. Here, the electrochemical biosensor for detecting cytokeratin 18 (CK18, bladder cancer biomarker) was constructed based on the chemically modified electrode (CME). The work electrode (WE) was modified by bismuth sulfide semiconductor nanocrystals (Bi2S3 NCs), and then immobilized with CK18 antibodies and blocking agents to complete the electrode preparation. The results indicated that the interface of a flexible carbon electrode with Bi2S3 NCs film was steady with reliable charge transfer capability. With the large specific area and quantum size effect, the proposed sensor could detect CK18 antigen protein with an ultralow detection limit of 1.87 fM (fmol L-1) and wide linear dynamic range of 1-1000 pg mL(-1), respectively. Detecting results could be read in less than 30 s with the portable, planar flexible CME. The sensitive and specific electrochemical biosensor possessed the characteristics of rapidity, ease-of-use, and non-invasive detection, indicating the application prospect in the early screening of bladder cancer and other diseases.