Fabrication And Application Of Electrochemical Sensor Interface Based On The Micro-/Nano-Materials

Currently, more and more attention was paid on the electrochemical biosensor filed.With the development of nanotechnology, various micro-/nano-materials play more keyroles in the fabrication of electrochemical biosensor. Therefore, desigining compositematerials with good conductitivity and biocompatiblity as a electrochemical sensorinterferce and a platform for the immobilization of protein/enzyme is very important. Inthis article, we made more efforts to synthesis two novel composite materials, includingAuNPs-carbon aerogel and polypyrrole-Co3O4,which were used for creating novelplatform to immoblize Hb or GOD in order to fabricate electrochemical biosensor.1. AuNPs-carbon aerogel (Au-CA) was prepared with ethylene glycol (EG)reducing method, and its morphology was characterized by electron microscopy (SEM)with energy dispersive spectrometer (EDS). Furthermore, a novel biocompatibleplatform based on Au-CA and ionic liquid (IL) was applied to the immobilization ofhemoglobin (Hb) for fabricating amperometric biosensor. Electrochemical andspectroscopic experiments demonstrated that the Au-CA/IL composites possed goodbiocompatibilty. The electrocatalytic property using hydrogen peroxide (H2O2) andnitrite (NO-2) as model compounds revealed fast responses (within7s), good dynamicresponse ranges and low detection limits (2.0μM for H2O2and1.3μM for NO-2).2. A novel organic-inorganic hybrid material polypyrrole-Co3O4(Ppy-Co3O4)was designed and synthesized, which was dispersed into ionic liquid (IL) for formationof stable composite films for the immobilization of Hemoglobin (Hb). The combinationof Ppy and Co3O4as well as IL created a platform with exceptional characteristics, and the content of Ppy had an effect on the direct electron transfer（DET）of Hb. Notably,when weight percentage of pyrrole monomer was20%, the heterogenous electrontransfer rate constant (ks) for Hb was caculated to be1.71s-1. In the meantime,electrochemical and spectroscopic measurements showed that Hb remained theirbioactivity, and achieved fast electron transfer on the Ppy-Co3O4/IL composite modifiedcarbon paste electrode. Furthermore, the Ppy-Co3O4/IL/Hb composite film modifiedelectrode was used as a biosensor and exhibited a long linear range and lower detectionlimit to H2O2. The apparent Michaelis–Menten constant (Km) were found to be0.53mM.3. Fllowing the last section, Ppy-Co3O4/IL composite film was also successfullyused for immobilization of glucose oxidase (GOD) on the carbon paste electrodes (CPE)surface, which was characterized by ultraviolet visible spectra (UV-vis), fouriertransform infrared spectra (FT-IR) and SEM. The results indicated GOD still can retainits original structure. Furthermore, the electrochemical measurements demonstrated thatthe DET was achieved between the modifide electrodes and GOD, and the heterogenouselectron transfer rate constant (ks) estimated to be1.67s-1. The sensing design based onthe Ppy-Co3O4hybrid material was demonstrated to be effective and promising indeveloping protein and enzyme biosensors.