Detection of vibrio cholerae O1 by using cerium oxide nanowires - based immunosensor with different antibody immobilization methods

In this work, we evaluated the effects of different antibody immobilization strategies on the response of a CeO 2 -nanowires (NWs)-based immunosensor for Vibrio cholerae O1 detection. Accordingly, the changes in the electron-transfer resistance ( R et ) from before to after cells bind to an antibody-modified electrode prepared by using three different methods of antibody immobilization were determined. The values were 16.2%, 8.3%, and 6.65% for the method that utilized protein A, antibodies activated by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS), and absorption, respectively. Cyclic voltammetry confirmed that the change in the current was highest for the immunosensors prepared using protein A (11%), followed by those prepared with EDC/NHS-activated antibodies (9%), and finally, those prepared through absorption (7.5%). The order of the antibody immobilization strategies in terms of resulting immunosensor detection limit and sensitivity was as follows order: absorption (3.2 × 10 3 CFU/mL; 45.1 Ω/CFU·mL −1 ) < EDC/NHS-activated antibody (1.0 × 10 3 CFU/mL; 50.6 Ω/CFU·mL −1 ) < protein A (1.0 × 10 2 CFU/mL; 65.8 Ω/CFU·mL −1 ). Thus, we confirmed that the protein A - mediated method showed significantly high cell binding efficiencies compared to the random immobilization method.