【作者】 张玲；

【导师】 何建平；

【作者基本信息】 南京航空航天大学 ， 材料物理与化学， 2019， 博士

【摘要】 光电化学（PEC）生物传感是将PEC过程和电化学生物传感相结合而发展起来的一种新型检测技术。PEC传感采取不同的激发和检测方式,具有灵敏度高、分析成本低等优势,已被广泛应用于免疫、核酸及细胞分析等领域。然而,由于起步较晚,PEC传感在高效光电功能界面的构建及高灵敏信号传输机制的开发等方面仍面临着诸多挑战。基于此,本论文以建立高灵敏PEC传感方法为研究目标,从光电功能材料的开发和信号传导策略的构建两个角度进行调控,探讨光电转换过程及相关信号传输机制。具体工作内容如下:1.Bi OI/葡萄糖氧化酶协同催化PEC酶传感分析利用浸渍-羟基化法在Ni O/ITO电极表面原位制备了Bi OI纳米片,有效提高了Ni O在可见光激发下的光电流响应。通过在Bi OI/Ni O/ITO异质结光敏阴极表面组装葡萄糖氧化酶（GOx）,基于GOx催化O₂氧化葡萄糖产生H₂O₂,电极光电流随H₂O₂浓度的增大而上升,实现了葡萄糖的信号增强型PEC传感。针对电极的光电流并没有因O₂的消耗而受到抑制这一特殊现象,我们对传感过程的可能机理进行了探讨,发现在Bi OI的类酶催化作用下H₂O₂具有比O₂更强的得电子能力。2.Cu O纳米管/Cu电极的制备及其光电阴极酶传感性能研究将表面氧化与控温退火相结合,在Cu箔表面原位制备了Cu O NTs。通过在Cu O NTs/Cu电极表面负载黄嘌呤氧化酶（XOD）,探讨了Cu O NTs和XOD的协同催化性能。在该体系中,XOD可催化O₂氧化鸟嘌呤产生H₂O₂,而H₂O₂又会进一步在Cu O NTs所具有的类似过氧化物酶的催化作用下得到电子产生活性氧。随着鸟嘌呤浓度的增加,电解质溶液中H₂O₂的含量会逐渐增大,进而引起Cu O NTs/Cu电极阴极光电流的显著增强,基于此,实现了鸟嘌呤的信号增强型PEC检测。3.基于Ag纳米团簇能量转移PEC DNA传感分析以DNA为模板,通过一步法实现了Ag纳米团簇（NCs）在DNA末端的原位修饰,并原创性地利用Ag NCs与Cd S量子点（QDs）间的能量转移作用构建了一种高灵敏的PEC DNA传感模型。在该体系中,我们以Cd S QDs修饰的ITO导电玻璃作为光敏电极,通过将可同时与目标DNA和一端修饰有Ag NCs的模板DNA进行互补配对的发夹DNA组装在Cd S QDs电极表面,实现Ag NCs在Cd S QDs/ITO电极表面附近的固定。在光激发下,相互靠近的Ag NCs与Cd S QDs会发生能量转移作用,进而诱导电极光电流的猝灭。该方法对目标DNA传感的线性范围为1.0 p M～10 n M,检出限为0.3 p M。4.基于聚合物量子点能量转移PEC端粒酶传感分析为避免镉系QDs潜在的细胞毒性对生物样品分析带来不利影响,我们以聚合物量子点（Pdots）为能量供体,Au纳米粒子（NPs）为能量受体,首次利用端粒酶（TE）对Pdots与Au NPs间的相对距离进行调控,进而影响能量转移作用,最终实现光电流信号的猝灭与恢复。通过监测TE加入前后Pdots/ITO电极光电流的变化,成功实现He La细胞裂解液中TE活性的PEC传感。更多还原

【Abstract】 As a new detection technology based on the photoelectrochemical（PEC）process,PEC bioanalysis features simple equipment and low background noise,and is becoming a promising analytical methodology.However,due to the short development time,some important challenges still remain in the construction of ultrasensitive PEC bioanalysis.For example,new type of highly efficient photoelectric functional interface and the novel signaling mechanisms still need to be exploited.To address these problems,based on the development of new functional materials in the preparation of photosensitive electrodes and the construction of sensitive signal sensing strategy and other applications,a series of reseach works had been carried out as described below.1.Bismuth oxyiodide couples with glucose oxidase:a special synergized dual-catalysis mechanism for photoelectrochemical enzymatic bioanalysisOn the basis of a special synergized dual-catalysis mechanism,this work reports the preparation of a Bi OI-based heterojunction and its use for cathodic photoelectrochemical（PEC）glucose biosensing which,unexpectedly,revealed that hydrogen peroxide（H₂O₂）had a greater impact than dioxygen（O₂）.Specifically,the Bi OI layer was in situ formed on the substrate through an impregnating hydroxylation method for the following coupling with the model enzyme of glucose oxidases（GOx）.The constructed cathodic PEC enzyme sensor exhibited a good analytical performance of rapid response,high stability,and good selectivity.Especially,This interesting phenomenon was attributed to a special synergized dual-catalysis mechanism,and the photoelectric functional material of Bi OI can also act as the peroxidase mimetics.2.Semiconducting Cu O nanotubes:synthesis,characterization,and bifunctional photocathodic enzymatic bioanalysisThis work reports the synthesis,characterization,and application of bifunctional semiconducting Cu O nanotubes（NTs）electrode for innovative synergized cathodic photoelectrochemical（PEC）enzymatic bioanalysis.Specifically,Cu O NTs electrode wa s fabricated by surface oxidation of the copper foil in an alkaline aqueous solution with（NH₄）₂S₂O₈and then annealed in air.After the subsequent coupling with the model enzyme of xanthin e oxidase（XOD）,the resulted photocathodic enzyme biosensor exhibited good analytical performance of rapid response,high stability,and good sensitivity.Especially,due to the unique catalytic property of Cu O toward H₂O₂,a novel enzymatic cascade design between biological catalyst（XOD）as natural enzyme)and biomimetic catalyst（Cu O as the peroxidase mimetics）was constructed,and the dual-catalyst system with special synergy effect could achieve the cathodi c PEC guanine bioanalysis with enhanced efficiency.In the determination,the cathodic photocurrent was found to be proportional to the guanine concentration,which was different from the commonly observed O₂-dependent suppression of the photocurrent.3.Ag nanoclusters could efficiently quench the photoreszaiponse of Cd S quantum dots for novel energy transfer-based photoelectrochemical bioanalysisHerein the influence of ultrasmall Ag nanoclusters（NCs）against Cd S quantum dots（QDs）in a photoelectrochemical（PEC）nanosystem was exploited for the first time,based on which a novel PEC bioanalysis was successfully developed via the efficient quenching effect of Ag NCs against the Cd S QDs.In a model system,DNA assay was achieved by using molecular beacon（MB）probes anchored on a Cd S QDs modified electrode,and the MB probes contain two segments that can hybridize with both target DNA sequence and the label of DNA encapsulate d Ag NCs.After the MB probe was unfolded by the target DNA sequence,the labels of oligonucleotid e encapsulated Ag NCs would be brought in close proximity to the Cd S QDs electrode surface,and efficient photocurrent quenching of QDs could be resulted from an energy transfer process that originated from NCs.Thus,by monitoring the attenuation in the photocurrent signal,an elegan t and sensitive PEC DNA bioanalysis could be accomplished.The developed biosensor displayed a linear range from 1.0 p M to 10 n M and the detection limit was experimentally found to be of 0.3p M.4.Gold nanoparticles-induced photocurrent quenching and recovery of polymer dots:toward signal-on energy-transfer-based photocathodic bioanalysis of telomerase activity in cell extractsUsing the innovative polymer dots（Pdots）-involved ET,this work reports the first signal-on and cathodic PEC bioanalysis toward telomerase（TE）activity in cell extracts.Specifically,the sequential binding of capture DNA（c DNA）,telomerase primer sequence（TPS）and Au NPs-labeled DNA probe（ADP）on the electrode would place the Au NPs in close proximity of Pdots,leading to obvious quenching of the cathodic photocurrent.The subsequent extension of the TPS by TE in the presence of deoxyribonucleoside triphosphates（d NTPs）would then release the ADP from the electrode,leading to the recovery of the photocurrent.On the basis of the Au NPs-induced photocurrent quenching and recovery of Pdots,a sensitive biosensor could thus be developed by tracking the photocurrents to probe the TE activity.This strategy allows fo r signal-on and cathodic PEC bioanalysis of TE,which can be easily extended for numerous other targets of interest.更多还原