Polymer-derived Carbon Nanocomposites Modifying Carbon Microeletrode For Electrochemical Biosenser

H₂O₂ plays an important role in the signaling and maintenance of normal cellular functions in biological cells.However,excessive amounts of H₂O₂ can lead to a variety of diseases in the body.Therefore,realizing ultra-sensitive detection of H₂O₂is of great significance for human health.Electrochemical biosensor based on microelectrode with excellent analytical sensitivity can meet the testing requirements.Modifying carbon fiber microelectrode with carbon nanostructures derived from carbon precursors and constructing a three-dimensional arrays structure can not only greatly enhance the surface area of the microelectrode,then fully contact with substance to be tested,but also introduce in active catalytic components（noble metal nanoparticles,nitrogen,boron,phosphorus and other heteroatoms）,so as to provide the feasibility for microelectrode to ultra-sensitive detect of H₂O₂ in cell samples.Owing to the demand of ultra-sensitive detection of H₂O₂ and the development of carbon fiber based microelectrode,two kinds of carbon fiber microelectrodes modified by polymer-derived carbon nanomaterials were developed.The electrochemical biosensor based on the microelectrode was employed to near-cell detecting H₂O₂ released by cancer cells.The main research contents of this paper are as follows:1.Based on the excellent film forming performance and high carbon yield of polydopamine（PDA）,3D nitrogen doped carbon nanotube arrays/active carbon fiber（N-CNTAs/ACF）microelectrode was prepared with PDA as the carbon precursor and ZnO nanorod arrays/activiated carbon fiber（ZnO-NRAs/ACF）as the template.N-CNTAs greatly increased the ACF surface area,and the interspace between N-CNTAs was conducive to the electrolyte molecules entering the active site.PdPt/N-CNTAs/ACF microelectrode was obtained by loading PdPt alloy nanoparticles on N-CNTAs/ACF by impregnation reduction.Due to the high catalytic activity of PdPt alloy nanoparticals and the synergistic effect among different components,the microelectrode has a good catalytic response to H₂O₂.The electrochemical sensor based on the microelectrode PdPt/N-CNTAs/ACF was used to in situ detect the H₂O₂ content secreted by liver cancer cells（HepG2）,cervical cancer cells（Hela）and breast cancer cells（MCF-7）.The results could be used to identify cell types and evaluate the radiotherapy effect.2.In order to further explore the influence of carbon precursor on morphology,structure and chemical properties of the derivate carbon nanomaterials.Nitrogen,boron,phosphorus doped porous carbon nanotube array modified activated carbon fiber（NBP-PCNTAs/ACF）microelectrode was synthesized with 1-vinyl-3-ethyl imidazole tetrafluoroborate（[VEIM]BF₄）polymer as the carbon precursor,1-octyl-3-methyl imidazole hexafluorophosphate（[OMIM]PF₆）as the heteroatom doping agent and the template of pore-forming agent.[VEIM]BF₄ self-polymerized when ZnO-NRs/ACF coated with[VEIM]BF₄ and[OMIM]PF₆ mixture was heated in the Ar atmosphere.During further high-temperature carbonization,[VEIM]BF₄polymer carbon precursor was transformed into nitrogen,boron doped carbon skeleton.[OMIM]PF₆ underwent thermal cracking,which resulted in the porous carbon structure with nitrogen and phosphorus heteroatoms doping into the carbon skeleton.The porous 3D arrays structure can not only increase the specific surface area of ACF,but also reduce the transfer resistance of reactants,then improve the chemical reaction rate.Heteroatom doping is beneficial to change the structure,charge density and electron cloud arrangement around carbon atoms,therefore,enhance the catalytic activity of the electrode.In addition,the synergistic effect of various heteroatoms makes the porous NBP-CNTAs/ACF microelectrode have good catalytic performance towards H₂O₂,which can be used for in situ sensitive detecting H₂O₂ released by HepG2,Hela and MCF-7.