【作者】 林涛；

【导师】 肖菲；

【作者基本信息】 华中科技大学 ， 材料化学， 2022， 硕士

【摘要】 细胞内过氧化氢（H₂O₂）与肿瘤的发生和转移关系密切,精准测定细胞体系H₂O₂含量对肿瘤的预防和诊断具有重要意义。微电极凭借尺寸小和响应迅速等优点,为细胞的电分析研究提供了强有力的工具。研究表明,在微电极表面构筑具有高表面积和高导电性的碳纳米管（Carbon nanotubes,CNTs）阵列结构可提高微电极的传感性能。基于此,本文采用金属修饰和元素掺杂策略构建了两种金属-碳纳米管阵列修饰的柔性微电极,探索其在实时电化学检测活细胞释放H₂O₂中的应用。主要研究内容如下:（1）采用单金属修饰和单元素掺杂策略制备高催化活性CNTs阵列。以Fe OOH阵列为金属催化剂模板,通过化学气相沉积法制备了氮掺杂碳纳米管封装铁-碳化铁纳米颗粒/碳纤维（Fe-Fe₃C@NCNTs/CF）微电极。由于Fe-Fe₃C和氮掺杂碳的良好催化活性,并且NCNTs阵列促使活性位点充分暴露,Fe-Fe₃C@NCNTs/CF展现出优异的类过氧化物酶活性和H₂O₂电催化还原性能。该微电极构建的H₂O₂电化学传感器的线性范围为0.5～6 400μM、灵敏度为628μA cm^-2 m M^-1、检出限为0.26μM,可用于原位检测人结肠癌细胞HCT116、SW48和结肠细胞NCM460释放的H₂O₂。（2）采用双金属修饰和双元素掺杂策略构建更高活性的CNTs阵列。通过喷墨打印和化学气相沉积法制备了三种过渡金属纳米颗粒嵌入硼氮共掺杂碳纳米管/碳纤维（M@BNCNTs/CF,M=Co,Fe,Ni）微电极;再以浸渍还原法在Co@BNCNTs/CF上负载Pt纳米颗粒（Pt-Co@BNCNTs/CF）,Pt的引入使Pt-Co@BNCNTs/CF具有类过氧化物酶活性,并提高了微电极的灵敏度和选择性。由于Pt、Co纳米颗粒和BNCNTs组成了丰富的活性位点,并且BNCNTs阵列有利于活性位点充分暴露,Pt-Co@BNCNTs/CF对H₂O₂检测性能优异,线性范围为0.5～9 400μM、灵敏度为1 679μA cm^-2 m M^-1、检出限为0.19μM,还展现出良好的选择性、重现性和稳定性。该微电极成功应用于检测人结肠癌细胞HCT116、SW48和结肠细胞NCM460释放的H₂O₂。更多还原

【Abstract】 The levels of hydrogen peroxide（H₂O₂）in cells are closely related to tumorigenesis and metastasis.Therefore,the precise determination of H₂O₂ in cells is of great significance for tumor prevention and diagnosis.Microelectrode is a powerful tool for electroanalysis of cells due to its characteristics of small size and rapid response.Research shows depositing carbon nanotubes（CNTs）arrays with high surface area and high conductivity on the surface of microlelectrode would improve its sensing performance.Hence,we have prepared two kinds of metal-CNT arrays modified flexible microelectrodes with the strategies of metal decorating and heteroatoms doping in this article,and explored their application in the real-time electrochemical detection of H₂O₂ released from living cells.The main research contents are as follows:（1）Taking the strategies of monometal decorating and single heteroatom doping,we have constructed CNT arrays with great catalytic activity.Herein,Fe-Fe₃C nanoparticles encapsulated in nitrogen doped carbon nanotubes/carbon fiber（Fe-Fe₃C@NCNTs/CF）microelectrode was prepared by chemical vapor deposition method using Fe OOH arrays as metal templated catalysts.Benefiting from the superior catalytic activity of Fe-Fe₃C and nitrogen doped graphitic carbon,as well as the NCNTs arrays enlarge the exposure of active sites,the resultant Fe-Fe₃C@NCNTs/CF microelectrode shows excellent peroxidase-like activity and performance for electrochemical H₂O₂ reduction.The H₂O₂ electrochemical sensor constructed by resultant microelectrode exhibits a linear range of 0.5～6 400μM,sensitivity of 628μA cm^-2 m M^-1,and a detection limit of 0.26μM,which was able to in situ detect H₂O₂ released from colorectal tumor HCT116,SW48 cells,and human colon NCM460 cells.（2）Taking the strategies of bimetal decorating and dual heteroatoms doping,we have fabricated CNT arrays with higher catalytic activity.Firstly,three transition metal nanoparticles embedded in boron-nitrogen co-doped carbon nanotubes/carbon fiber（M@BNCNTs/CF,M=Co,Fe,Ni）microelectrodes were fabricated by inkjet printing and chemical vapor deposition.Then,Pt-Co@BNCNTs/CF was obtained with Pt nanoparticles loaded on Co@BNCNTs/CF via impregnation-reduction process.The introduction of Pt not only make Pt-Co@BNCNTs/CF with peroxidase-like activity,but also improve the sensitivity and selectivity of microelectrode.Owing to the abundant active sites composed of Pt nanoparticles,Co nanoparticles and BNCNTs,as well as BNCNTs arrays could enhance the number of exposed active sites,the resultant Pt-Co@BNCNTs/CF exhibits superior performance for H₂O₂ detection.It shows a linear range of 0.5～9 400μM,high sensitivity of 1 679μA cm^-2 m M^-1,and a detection limit of 0.19μM,as well as great selectivity,reproducibility,and stability.More importantly,this microelectrode was successfully applied to detect H₂O₂ released from human colorectal tumor HCT116,SW48cells,and human colon NCM460 cells.更多还原