Electrochemical Biosensing Based On The Redox Proteins Composite Film Modified Electrode

Many researchers have paid high attention to the electrochemistry biosensorresearch of hemoglobin (Hb) and glucose oxidase (GOD). Because it is veryimportant for exploring the physiological mechanism, the materials metabolism andenergy conversion in organisms, and fabricating the novel biosensors.In this paper, in order to realize the direct electrochemistry and electro-catalysisof Hb and GOD, several kinds of materials with excellent biocompatibility wereselected to as novel composite films to immobilize enzymes. These novel compositecarriers provide favourable microenvironment for the enzymes to keep their biologicalactivities, meanwhile facilitate the direct electron transfer between the enzymes andthe electrodes, and enzymes immobilized in these composites performed outstandingelectrocatalytic properties towards theirs own substrates. The main work in this paperwas summarized as follows:(1) Thanks to the excellent biocompatible ability of the quaternized cellulosenanoparticles (QCs), we built a novel composite film based on the QCs and acetyleneblack (AB) to immobilize hemoglobin. Because AB has many favourable characters,such as large specific surface area, super capacity of accumulation, and excellentelectric conductivity, QCs/AB composite film not only can provide favourablemicroenvironment for Hb, but also facilitate the direct electron transfer between Hband the electrode. The characterization of Hb/QCs/AB composite film wasdemonstrated by ultraviolet–visible (UV-vis) spectra and electrochemical impedancespectroscopy (EIS). The results indicated that Hb immobilized in the composite filmstill maintained its bioactivity，and showed high electrocatalytic effect towards theH2O2.(2) A novel composite film based on the quaternized cellulose nanoparticles(QCs) and acetylene black (AB) was prepared to immobilize glucose oxidase (GOD).Because QCs display excellent biocompatible and high adsorption of proteins, AB hasmany outstanding characters, such as largely specific surface area, super capacity ofaccumulation, and excellent electric conductivity, QCs/AB composite film not onlycan provide favorable microenvironment for GOD, but also facilitate the directelectron transfer between GOD and the electrode. The results indicated that GODimmobilized in the composite film still maintained its bioactivity, and showed highelectrocatalytic effect towards the reduction of glucose. (3) Glucose oxidase was successfully entrapped in the hybrid film withcombined the outstanding performance of β-cyclodextrin (β-CD) covalentlyfunctionalized single-walled carbon nanotubes (SWCNTs) and cetyltrimethylammonium bromide (CTAB). Thanks to the unique features of the hybrid film, suchas the excellent biocompatible ability and electric conductivity, we successfullyestablish a novel platform to promote the direct electron transfer between GOD andthe electrode. The characterization of GOD/β-CD-SWCNTs hybrid film wasdemonstrated by scanning electron microscope (SEM) and electrochemical impedancespectroscopy (EIS). The results indicated that GOD immobilized in the hybrid filmrealized the direct electrochemistry of GOD, showed high electrocatalytic activitytowards the reduction of glucose, and possible interfering species didn’t interfere withthe determination of glucose.