新型金银纳米复合材料及其医学与环境传感检测应用

【作者】 刘敏；

【导师】 王桦；

【作者基本信息】 曲阜师范大学 ， 分析化学， 2018， 硕士

【摘要】 金（Au）和银（Ag）等贵金属纳米材料具有良好的导电性、催化活性和光电特性,在光电催化和医学传感等领域具有广泛的应用。本文借助三聚氰胺（MA）的高吸附性能和氧化锌（ZnO）的光催化功能,并将其与Au或Ag纳米材料相结合,用以修饰电极或作为传感探针,分别实现了硫化物、谷胱甘肽（GSH）、尿酸（UA）、甲醛等的分析,具体包括:（1）通过可控的超分子自组装途径,合成了一种Ag-MA介孔纳米复合材料,进而将其修饰于电极表面,实现了高盐体系中多种硫化物的电分析（第2章）。研究表明,通过控制Ag与MA的比例,可制得线状和棒状两种形貌的Ag-MA纳米复合材料,而线状Ag-MA修饰电极可获得稳定、尖锐的固相AgCl氧化峰（峰电位接近于零）,有效地避免了背景中共存的其它电活性物质的干扰。更重要的是,引入硫化物后,利用特定的S-Cl间置换反应,电极上的AgCl被置换为Ag₂S,从而导致AgCl氧化峰信号的降低。采用该电化分析技术分别实现了血液和废水等高盐介质中多种硫化物(H₂S/S^2-、S_x^2-、S₂O₃^2-和半胱胺酸)特异、灵敏的传感分析(其中,血液中S^2-的检测限为0.24μM)。（2）建立了一种基于Ag掺杂Zn O（Ag-ZnO）纳米复合材料的微孔电分析方法,并将之应用于细胞中GSH的检测（第3章）。以非水溶胶-凝胶法合成Ag-ZnO纳米复合材料,用以结合十八烷基三氯硅烷（OTS）,在ITO电极上制得超疏水Ag-ZnO-OTS涂层,进而利用Ag-ZnO的光催化作用,在紫外光照射下改变OTS的亲疏水状态,从而在超疏水涂层上制得超亲水微孔。研究表明,借助微孔与周围基质间的超润湿性差异,可高效富集溶液中的微量分析物;同时该电极可在接近零电位处获得稳定、尖锐的固相AgCl氧化峰。特别是,借助GSH中巯基与AgCl中Ag的强相互作用,可使电极上固相AgCl信号降低,由此实现对细胞样品中GSH灵敏、特异的电分析,检测限约为11.25 pM。（3）开发了一种基于Au-MA纳米复合材料的血液UA的电分析技术（第4章）。以MA为还原剂一步合成了Au-MA纳米复合材料,并将其修饰于电极表面,借助具有高比表面积的MA聚合物对UA的高效吸附,以及纳米金的高导电性与电催化活性,并结合UA氧化峰电位随pH值变化的现象,实现了对血液中UA的特异性电分析,检测限为0.54μM。（4）采用超分子自组装途径合成Ag-MA纳米复合材料并将其附着于试纸条上,用于水溶液中甲醛的可视化检测（第5章）。实验发现,该试纸条借助Ag-MA复合材料对甲醛的高效吸附与结合,并在碱性条件下利用甲醛将Ag-MA中的Ag还原成可视化黑色沉淀,通过测定其固相反射光强度,实现了对甲醛的速测和可视化比色分析。该方法对水溶液中甲醛检测的线性范围为0.1-22.0μM,检测限为0.039μM。更多还原

【Abstract】 Gold（Au）and silver（Ag）noble metal nanomaterials with good electrical conductivity,catalytic activity,and photoelectric properties have been widely used in photocatalysis and medical sensing fields.In the thesis,the high adsorption performance of melamine（MA）and the photocatalysis of zinc oxide（ZnO）were utilized introduced.Moreover,some Au and Ag noble metal nanocomposites were synthesized to modify the electrodes or used as functional probes for the sensitive and specific analysis of sulfides,glutathione（GSH）,uric acid（UA）,and formaldehyde.These contents mainly include:（1）A kind of Ag-MA mesoporous nanocomposites were synthesized through a controlled supramolecular self-assembly pathway,which was then modified on the electrode surface to achieve the electrical analysis of multiple sulfides in high salt medium（Chapter 2）.The results show that wirelike and rodlike Ag-MA nanocomposites were prepared by controlling the ratios of Ag and MA.The electrode modified with wirelike Ag-MA nanocomposites were found to show a stable and sharp electrochemical oxidation peak of solid-state AgCl（the peak potential is close to zero）,which could effectively avoid the interference of other electrically active substances coexisting in the background.More importantly,after the introduction of sulfides,the yielded AgCl signals would decrease through the specific sulfide-chloride replacement reaction towards the transferring of AgCl into Ag₂S.The so established electrochemical analysis technique can allow for the specific and sensitive analysis of multiple sulfides(H₂S/S^2-,S_x^2-,S₂O₃^2-,and cysteine)in high salt media such as blood and wastewater,achieving the detection limit of S^2-ions in blood down to 0.24μM.（2）A microwell electrode was fabricated with Ag-doped ZnO（Ag-Zn O）nanocomposites for the detection of GSH in cells（Chapter 3）.The superhydrophobic coating was prepared on ITO plate using octadecyltrichlorosilane（OTS）and Ag-ZnO nanocomposites that were prepared through a sol-gel route.Furthermore,the microwell modified electrode was prepared by use of the photocatalysis of Ag-ZnO that would catalyze OTS to yield the superhydrophilic microwell.Benefitting from the super-wettability difference between the microwell and the surrounding substrate,the microwell modified electrode can efficiently enrich the trace analytes from the solution.A stable and sharp solid-state AgCl electrochemical oxidation peak could be obtained at near zero potential.Especially,due to the strong interaction of thiols in GSH and Ag in AgCl,the solid-state AgCl signals on the microwell modified electrode would be reduced.A sensitive and specific electroanalysis method has thereby been achieved for probing GSH in cell samples,with the detection limit of about 11.25 pM.（3）An electrical analysis technique has been developed for the UA in blood based on Au-MA nanocomposites（Chapter 4）.Through using MA as the reducing agent,the Au-MA nanocomposites were first synthesized and then modified onto the electrodes.It was found that UA could be efficiently adsorbed onto the Au-MA modified electrodes by taking advantage of the large volume-to-surface area of MA in Au-MA nanocomposites.Moreover,the prepared eletrodes would benefit from the high conductivity and electrocatalytic activity of Au nanoparticles in Au-MA nanocomposites.Based on the pH-denpending oxidation peak potentials of UA,the developed Au-MA modified electrodes could facilitate the specific electroanalysis of UA in blood,showing the detection limit of 0.54μM.（4）The test strips were fabricated using Ag-MA nanocomposites that were synthesized by supramolecular self-assembly for the visual detection of formaldehyde in water（Chapter 5）.It was found that the test strips enabled the efficiently covalent adsorption for formaldehyde with the aid of Ag-MA nanocomposites,of which the silver components would be reduced to form a visible black precipitate under the alkaline condition to be further measured by the solid phase reflectance.Rapid and visual colorimetric analysis of formaldehyde could be realized in the linear range of 0.1-22.0μM,with the detection limit of 0.039μM.更多还原