The Fabrication And Application Of Non-enzyme Electrochemical Sensor Based On Novel Nano-materials

Electrochemical sensors have some outsanding advantages including excellent selectivity, high sensitivity, rapid response, easy to be miniaturized and automation. Therefore, they have potential applications in biology, environmental monitoring, chemical measurements in the agriculture and food industry. Nanostructured materials as new material are attractive in the developement of biosensors due to their novel optical, electrical, catalytic properties and favorable biocompatibility. With the introduction of nanomaterials, the performance of biosensor has a greatly improvement. Futhermore, the performance of the resulting sensors could be greatly improved with the application nanomaterials.In this paper, we developed novel electrochemical sensors for selective and sensitive analytical applications based on functionalized nanomaterials. Meanwhile, we summarized the experimental ideas and the research purposes of this thesis. In this thesis, Pt@BSA, multi-walled carbon nanotubes（MWCNTs） and molybdenum disulfide/gold nanoparticles（Mo S₂-Au） were applied for the fabrication of electrochemical sensors. The major contents in this thesis are deseribed as fllows:（1） The two-dimensional（2-D） Mo S₂ nanosheets were first in-situ assembled with Au nanoparticles, polyethylenimine（PEI） and Hemin molecules then were immobilized on the Mo S₂-Au-PEI film modified glassy carbon electrode（GCE） via amide bond. The Mo S₂-Au-PEI-hemin based-electrochemical non-enzymatic sensor was used to detect Clenbuterol（CLB）. The proposed electrochemical sensor showed a wide linear ranging from 10 ng/m L to 2 μg/m L and a detection limit（LOD） of 1.92 ng/m L CLB（S/N=3） with favorable reproducibility and stability. Furthermore, this presented method could be feasible for the detection of CLB in the real pork samples.（2） An electrochemical non-enzymatic sensing platform was developed based on multi-walled carbon nanotubes（MWCNTs）and polyethylenimine（PEI） loaded on the glassy carbon electrode（GCE）. With the good biocompatibility of MWCNTs-PEI, the nanocomposites could be facilely adhered to the electrode surface by Ï€-Ï€ bonds. Electrochemical methods containing cyclic voltammetry（CV） and differential-pulse voltammetry（DPV） were used to study the direct redox reactions and electrocatalytic behaviors of bisphenol A（BPA）. The sensor exhibited good electrocatalytic activity, high sensitivity and selectivity. The current response is linear over BPA concentration ranging from 10 n M to 50 μM with a detection limit（LOD） of 3.3 n M BPA（S/N=3）. Meanwhile, validation of the applicability of the sensor was carried out by determining BPA in real milk samples.（3） The use of a non-enzymatic electrochemical sensor, comprised of biomimetically synthesized Pt@BSA microspheres, for the detection of hydrogen peroxide（H2O2） was described. The Pt@BSA composite microspheres were immobilized on Au electrodes via Au-thiol bonds. The immobilization of Pt@BSA composite microspheres onto Au electrodes was thought to increase the electrode surface area and showed good electrocatalytic activity for reduction of H2O2. The reduction peak currents have a linear response to H2O2 concentration in the range of 5 μM 2.5 m M with a detection limit of 1.6 μM（S/N= 3）. Therefore, the Pt@BSA nanocomposite film could be used as promising platform for detecting H2O2.