Poly(pyrrole-co-pyrrole propylic acid) film and its application in label-free surface plasmon resonance immunosensors

In this work, surface plasmon resonance (SPR) was used to study protein immobilization on poly(pyrrole-co-pyrrole propylic acid) (PPy/PPa) for immunosensing applications. SPR was employed to in situ monitor the electropolymerization process and to control thickness of the PPy/PPa copolymer film. Goat IgG as a model protein was covalently immobilized on the carboxyl-containing film through EDC/NHS as the coupling reagents. The effect of pyrrole propylic acid (Pa) proportion in the deposition solution on the protein immobilization capability was systemically investigated. The immobilization efficiency was demonstrated by a label-free SPR immunosensor. The heterogeneous kinetics of the immune reaction was discussed. This work could provide a facile method to immobilize proteins on an electrode surface by electropolymerized copolymer, and renders a universal approach to in situ study the protein immobilization process and sensing kinetics for scientific insights of the heteroimmunosensing scheme particularly in surface chemistry and molecular biology for further improvement of immunosensors.