DISPOSABLE IMMUNOSENSOR FOR ESCHERICHIA COLI O157:H7 BASED ON A MULTI-WALLED CARBON NANOTUBE-SODIUM ALGINATE NANOCOMPOSITE FILM MODIFIED SCREEN-PRINTED CARBON ELECTRODE

摘要

A disposable immunosensor for the detection of Escherichia coli O157:H7 based on a multiwalled carbon nanotube-sodium alginate nanocomposite film was constructed. The nanocomposite was placed on a screen-printed carbon electrode, and horseradish peroxidaselabeled antibodies were immobilized to E. coli O157:H7 on the modified electrode to construct the immunosensor. The modification procedure was characterized by atomic force microscopy and cyclic voltammetry. Under optimal conditions, the proposed immunosensor exhibited good electrochemical sensitivity to E. coli O157:H7 in a concentration range of 10~3-10~(10) cfu/mL, with a relatively low detection limit of 2.94×10~2 cfu/mL (S/N=3). This immunosensor exhibited satisfactory specificity, reproducibility, stability, and accuracy, making it a potential alternative tool for early assessment of E. coli O157:H7.