Novel potentiometric immunosensor for the detection of diphtheria antigen based on colloidal gold and polyvinyl butyral as matrixes

摘要

A novel potentiometric immunosensor for the detection of diphtheria antigen(Diph)has been developed by means of self-assembly to immobilize diphtheria antibody(anti-Diph)on a platinum electrode based on colloidal gold(Au)and polyvinyl butyral(PVB)as matrixes.The modification procedure was characterized by electrochemical impedance spectroscopy(EIS)and cyclic voltammetry(CV).The interaction of antigen with grafted antibody recognition layers was carried out by soaking the modified electrode into a phosphate buffer solution at pH 7.0 with various concentrations of antigen.The detection is based on the change in the electric potential before and after the antigen-antibody reaction.Tests relating to the detection of diphtheria antigen demonstrate that the potentiometric immunosensor exhibits high sensitivity,wide linear range from 4.4 to 960 ng mL~(-1)with a detection limit of 2.4 ng mL~(-1),rapid response and long-term stability.