Study On The Electrochemical Biosensor Based On Nanoparticles

Objective(1) We synthesized carboxyl of multi-walled carbon nanotubes (MWCNTs), and then MWCNTs was assembled on the CS filmmodified glassy carbon electrode. The direct electrochemical behavior of octyl phenol (OP) was studied on the modified electrodes.(2) We synthesized TiO2nanoparticles, and TiO2and Hb were used to construct the {Hb/TiO2}n multilayer film for bionic functional interface on the CS modified GCE by layer-by-layer (LBL) assembly. The direct electrochemical behavior of Hb on the bionic functional interface was studied, and then a new H2O2biosensor was fabricated.(3) We prepared PDMS chip, then studied EOF of capillary electrophoresis with pure water as neutral marker, and optimized the experiment condition.Methods(1) We synthesized carboxyl of multi-walled carbon nanotubes (MWCNTs), and then MWCNTs was assembled on the CS film modified glassy carbon electrode. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis absorption spectra, electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and other methods were applied to characterize the NPs and the modified process of the glassy carbon electrode. The direct electrochemical behavior of octyl phenol (OP) was studied on the modified electrodes.(2) We synthesized TiO2nanoparticles, and TiO2and Hb were used to construct the {Hb/TiO2}n multilayer film for bionic functional interface on the CS modified GCE by layer-by-layer (LBL) assembly. TEM, SEM, UV-vis absorption spectra, EIS and CV were adopted to characterize the nanoparticles and assembly process of Hb. The direct electrochemical behavior of Hb on the bionic functional interface was studied, and then a new H2O2biosensor was fabricated.(3) We prepared PDMS chip, then studied EOF of capillary electrophoresis with pure water as neutral marker, and optimized the experiment condition.Results(1) The SEM stated clearly MWCNTs relatively uniform in CS membrane surface. The EIS characterization results showed that MWCNTs has been successfully fixed to the electrode surface. The Constructed electrochemical sensors peak current for OP with the concentration presented good linear related in8.33×10-8-2×10-5mol/L, Ipa=0.00167+77.36982[OP](mmol/L), correlation coefficient R=0.9994, detection limit for1.67×10-8mol/L (S/N=3). The results Showed that MWCNTs-CS modified GCE for the determination of OP is satisfactory.(2) The TEM spectroscopy confirmed successful synthesis of the TiO2nanocomposite, and the size of the nanocomposite was about10nm. UV-vis absorption spectra and EIS demonstrated that the {Hb/TiO2}n multilayer film was fabricated successfully. Hb immobilized in the multilayer film demonstrated excellent electrocatalytic reduction ability to H2O2, and there was a tremendous linear relationship between the current and the concentration of H2O2from0.20μmol/L to3000μmol/L, and the detection limit was0.10μmol/L (S/N=3). In the CV, LBL film showed at the reversible peak and the position of the redox and oxidation peaks located in0.38V and0.28V (vs. SCE). Along with the increase of assembly layer, peak position almost did not migrate. Therefore, the nanoparticles can provide appropriate micro environment for direct the electronic transfer of Hb.(3) The PDMS chip was successfully prepared. With the current monitoring method, pure water was the netral maker to determine the EOF in microchip electrophoresis. The experimental results showed that this method can effectively distinguish the naked and the gold nanoparticles modified PDMS microchannel. Comparing with many approaches for the measurement of EOF in microchip electrophoresis, this approach we proposed has less contamination and better reproducibility, which can be used as a simple, routine and meaningful method to observe EOF in microchip electrophoresis. Conclusion(1) The MWCNTs NPs were synthesized successfully, OP was assembled on the MWCNTs-CS modified GCE. The direct electrochemical behavior of octylphenol (OP) was studied on the modified electrodes.(2) TiO2nanoparticles was synthesized successfully, Hb can be immobilized on the nanocomposite to construct the {Hb/TiO2}n multilayer film by LBL assembly, then a bionic functional interface was fabricated, the direct electrochemistry of Hb in the multilayer film can be realized, and the electrochemical biosensing to H2O2was completed.(3) We prepared PDMS chip, then studied EOF of capillary electrophoresis with pure water as neutral marker, and optimized the experiment condition.