The Preparation Of Gold Nanoparticle-graphene Hollow Microspheres And The Electrochemical Study Of Myoglobin Composite Film Modified Electrode

In this paper,gold nanoparticles functionalized graphene hollow microspheres was synthesized with the method of Spray drying technology.Highly sensitive biosensor of gold nanoparticles functionalized graphene hollow microspheres/chitosan/myglobin composites has been demonstrated.It was prepared by incorporating myoglobin?Mb?within gold nanoparticles functionalized reduced graphene oxide hollow microspheres?AuNPs/rGO HMS?and chitosan?CS?.The fabrication procedure and properties of the composite films was characterized by scanning electron microscopy?SEM?,UV-vis absorption,and cyclic voltammetry?CV?,alternating current impedance?AC impedance?,square-Wave Voltammetry?SWV?and amperometry were taken to characterize.UV-vis experiments demonstrated that Mb in Mb-CS-AuNPs/rGO HMS films retained its secondary structure similar to its native states.The influence of pH external solution on the Soret band for the modified films was also tested.The results suggest that Mb in the composite films essentially keeps its original structure in the medium pH range,but in more acidic or more basic conditions,Mb in the CS-AuNPs/rGO HMS films may denature to a considerable extent.The composite Mb-CS-AuNPs/rGO HMS films modified on the glassy carbon electrode?GCE?showed a pair of well defined,quasireversible peaks at about-0.41 V vs saturated calomel electrode?SCE?at pH 7.0.Electrochemical parameter of Mb immobilized in the composite film such as apparent heterogeneous electron transfer rate constant?k_s?and formal potential(E^o?)were estimated by fitting the data of square-wave voltammetry with nonlinear regression analysis.The dependence of E^o?on solution pH indicated that the DET reaction of Mb was coupled with proton transfer.In addition,Experimental data demonstrated that Mb in the films exhibits excellent electrocatalytic properties towards various substrates such as hydrogen peroxide,oxygen,nitrite and trichloroacetic acid with lower detection limit,wider linear range and better stability,which have biological and environmental significance.These results suggested that the Mb-CS-AuNPs/rGO HMS composites film is a promising potential to be applied in developing novel electrochemical bioreactors and biosensors.