Using an Electrochemical Immunosensor Based on Polypyrrole Nanowire Arrays/Carboxyl Graphene Composite Modified Microelectrodes to Detect Periodontal Bacteria

An electrochemical immunosensor based on polypyrrole nanowires array/carboxyl graphene modified gold interdigitated array microelectrodes was developed to quantify periodontal bacteria. We prepared the polypyrrole/reduced carboxyl grephene composite nanostructures through one step cyclic voltammetry method. The present method could simplified polymerization process, while maintained excellent conducitivity of the composite nanostructures. Then we could immobilized antibodies directly on composite nanostructure surfaces through chemical activation of carboxyl groups. The results demonstrated that PPy nanowires were coated with reduced carboxyl grephene. The impedance value increased significantly after antibody immobilization and bacteria adsorption. The linear dectection range was 103 to 109 cells/mL. The developed immunosensor had a good reproducibility and sample recovery rate. The relative standard deviation was small, which showed the potential application value of the immunosensor for periodontal bacteria detection in clinical samples.