Direct Electrochemistry And Biosensing Of Redox Protein Or Enzyme Based On Nanomaterials

Redox proteins and enzymes were chosen as the research objects in this paper. Thecomposite membrane composed of nanomaterials and redox proteins was immobilized on thesurface of electrode by the simple coating method. Several electrochemical biosensors wereconstructed.Silver nanoparticles (AgNPs) and redox proteins were immobilized by the coatingmethod on the surface of glassy carbon electrode through the mixture of chitosan (Chit)-multi-walled nanotubes (MWNTs). A composite membrane electrode modified byChi-MWNTs/redox proteins/AgNPs was obtained. Meanwhile, a new hydrogen peroxide(H2O2) biosensor was successfully fabricated. The synergistic effect of of Chit-MWNTs andAgNPs could easily realize the direct electrochemistry of redox proteins. What’s more, theproposal membrane electrode could show excellent electrocatalytic activity towards H2O2andcould provide new thoughts for the preparation of the third generation biosensor based onredox proteins.A novel core@shell nanomaterial (simplied as Au@Au2S2O3) was synthesized accordingto the literature reported previously. It was applied to the construction of biosensors for thefirst time. Therefore, another membrane electrode composed of core@shellnanomaterial-hemoglobin (Hb)/Chit-MWNTs was successfully fabricated. Moreover, westudied the microscopic structure of the composite membrane and the direct electrochemistryand electrocatalysis of Hb by TEM, UV-Vis method and electrochemical methods.Consequently, a novel electrochemical biosensor was developed.Single-walled nanotubes (SWNTs) and chitosan were mixted with each other under theacidic condition. Glucose oxidase (GOx) was immobilized on the surface of gold electrode bycoating and electrostatic interactions. We successfully realized the direct electrochemistry ofGOx. During the catalytic process, the intermedia, hydroxyl ferrocene, facilitated the electrontransfer between GOx and electrode efficiently, indicating that it has an excellent electrocatalytic activity. It also demonstrates that this is a typical reaction catalyzed byenzyme-based. The biosensor is suitable for the reagentless detection of GOx.