Disposable Polyurethane Nanospiked Gold Electrode-Based Label-Free Electrochemical Immunosensor for Clostridium difficile

A polyurethane (PU) nanospiked gold electrode-based label-free electrochemical immunosensor for Clostridium difficile (C. difficile) toxin B detection was developed. Different from nanomaterial-modified electrodes, the PU nanospiked gold electrode was fabricated by soft lithography directly. The morphology of the nanospiked electrode was characterized by scanning electron microscope (SEM), and its good electrochemical performance was demonstrated by cyclic voltammetry (CV) as well as differential pulse voltammetry (DPV). Then, the PU nanospiked gold electrode-based immunosensor was developed by fixing antitoxin B single domain antibody on the electrode surface as the receptor. DPV was used as a detection technology for C. difficile toxin B detection. It revealed that the immunosensor has good specificity, repeatability, and stability. Even in a label-free style, the limit of detection for toxin B was 0.5 pg/mL. In the concentration range of 1–130 pg/mL, the linear regression equation ΔI = −1.216[C] – 41.62 was found; the correlation coefficient R2 was 0.9839. Compared with the flat PU electrode-based immunosensor, the detection signal of the PU nanospiked gold electrode-based immunosensor was amplified about 6 times. Benefiting from its low cost and simple processing, the PU nanospiked gold electrode-based immunosensor can be used as a disposable electrochemical sensor for toxin B rapid detection.