Direct Electrochemistry And Electrochemical Biosensors Of Hemoglobin Based On Nano Compite Films

Direct electron transfer between redox proteins and electrodes has attracted moreand more attention in recent years. Based on these studies, we can get usefulinformation about the reaction mechanism of biological electron transfer, research thephysiological function and its mechanism of redox proteins in vivo, understandsubstance metabolism and energy transformation in vivo, as well as importantsignificance for the further development of the medicine, biosensor, bioelectrocatalytcsystem. This paper is mainly to study the direct electrochemistry and electrochemicalbiosensing of hemoglobin, several good biocompatibility nano composite films wasprepared. These films provided a good biomicroenvironment for hemoglobin andkeeped its bioactivity.The composite film entrapped hemoglobin inmodified glassycarbon electrode, hemoglobin realized direct electron transfer using cyclicvoltammetry, and keep the electroactivity to its substrate catalytic ability. The mainwork in this paper are as follows:(1) Quaternized cellucose functioned nano gold (quaternized cellucosefunctioned nano gold,Au@QC) was prepared and combined with poly ethyleneglycol diglycidyl ether (poly ethylene glycol diglycidyl ether, PEGDGE) to obained anano compoite films. Hemoglobin (hemoglobin,Hb) was successfully entrapped intothis a nano compoite films and built a new type of biosensor by using conductivityand biocompatibility of Au@QC and PEGDGE. The characterization of Au@QC andPEGDGE film was demonstrated by ultraviolet–visible spectra,scanning electronmicroscopy and electrochemical impedance spectroscopy (EIS). Hemoglobinentrapped in Au@QC and PEGDGE composite membrane realized its directelectrochemistry. Meanwhile, this biosensor has good electrocatalytic ability toreduction of nitric oxide(nitric oxide, NO).(2) A composite film of graphene oxide and poly ethylene glycol diglycidyl etherwas parpared. Hemoglobin wad entrapped succfully into this comsite film bynon-covalent manner and realized its direct electron tranfer on glassy glassy carbonelectrode,the rasults showed this composite film keeped the bioactivity of hemoglobin.A pair of well-defined and quasi-reversible redox peaks were observed and the formalpotential was about-0.331V in pH7.0phosphate buffer solution. Those resultsshowed composite film GO/PEGDEG is with high conductivity and goodbiocompatible.What’more,the hemoglobin entrapped in graphene oxide and polyethylene glycol diglycidyl ether has good electrocatalytic ability to nitric oxide and hydrogen peroxide.(3) Hemoglobin wad entrapped succfully into a biocompatide composite film ofgraphene oxide and Poly (N, N-dimethyl acrylamide)(PDMA).The characterizationof graphene oxide and PDMA film was demonstrated by electrochemical impedancespectroscopy (EIS) and scanning electron microscopy.The direct electrochemistry ofhemoglobin was studied. In addition the biosensor has good electrocatalytic ability tonitric oxide and hydrogen peroxide.The graphene oxide and PDMA and hemglobinmodified electrode showed long-term stability，good reproducibility and wide linearrange with a low detection limit.