Nano-assembly of glucose oxidase on the in situ self- assembled films of polypyrrole and its optical, surface and electrochemical characterizations

摘要

An in situ self-assembly technique withnanometre control over thicknesses and multilayered structureswas used to manufacture the ultrathin films of polypyrrole(PPY). The PPY film was deposited on a polyanion,poly(styrene sulfonate) (PSS) modified surface as a function oftime, previously PSS had been deposited on various substrates(glass, mica, indium-tin-oxide coated glass plates). Later,alternate PPY and PSS films were fabricated on such substratesusing a layer-by-layer (LBL) technique. The glucose oxidase(GOD) molecules were also deposited on such self-assembledPPY films by the LBL technique. The PSSIPPY/GOD,PPY/PPY/GOD/poly (ethylene imine) (PEI)/GOD etc, filmconfigurations were fabricated, and functionally as well asstructurally characterized by UV-visible, electrochemical andscanning probe microscopy techniques, respectively. The resultsof a scanning probe microscopic study on the films wereanalysed to understand the molecular orientation of GOD on thePPY surface, and the dependence of the enzyme concentrationfor the depositing solutions. Moreover, the electrochemicalstudies performed provided information with respect to theelectron transfer processes on the spatial arrangement of GODmolecules on the PPY surfaces. The immobilization of GOD ona conductive PPY represented a crucial and important step, andallowed us to construct the glucose-responsive biosensors.