纳米结构膜电致化学发光偏振调制及其生物分析应用研究

More structural information of bio-substances can be obtained by the interactions between the polarized light and biological substances. Thus, preparation of nanomaterial film with specific structures to realize polarized electrochemiluminescence (ECL) is of great theoretical and practical value to polarization modulation of ECL from nanostructured film and to development of new analytical techniques based on ECL. On the basis of the existing literatures and researching background, this project aims to prepare a series of two-dimensional few-layered nanosheets and semiconductor nanomaterials with excitonic emission. Noble metal nanocluster arrays and ferromagnetic thin films (Fe, Co) are firstly deposited on the surface of working metal electrode respectively. The ordered nanostructured film is constructed on noble metal nanocluster array/electrode to realize linearly polarized ECL, while circularly polarized ECL is obtained on the nanostructured film built on ferromagnetic thin film/electrode. The effects of size of noble metal nanocluster, the thickness of ferromagnetic layer, layer number of nanosheet and the shape and size of semiconductor nanomaterials on polarization are explored in a try to determine the conditions to obtain the maximum polarization. The main factors affecting the polarized ECL modulation are studied, based on which the corresponding physical model is built and the mechanism of polarized ECL generation in nanostructured film is revealed. The nanostructured films with maximum polarized ECL are applied to the detection of biological targets and study of structure change of bio-substances. The successful implementation of this project will provide theoretical basis for the modulation of polarized ECL and understanding the relationship between the change in structures and properties of biological substances and disease.

偏振光与生物物质的相互作用可以获得更多有关生物物质结构的信息，因此设计具有特定结构的纳米材料膜，实现膜的偏振电致化学发光（ECL），对于纳米结构膜ECL发射偏振调制及开发新的基于ECL的分析新技术具有重要的理论与实践价值。在已有的研究基础与文献支持下，本项目拟制备一系列具有激子发射的二维少层纳米板及半导体纳米材料。在金属电极表面生长贵金属纳米簇序列及铁磁材料薄层（Fe,Co）。在电极/贵金属纳米簇序列上构建有序纳米结构膜，实现线偏振ECL。在电极/铁磁材料薄层上构建具有圆偏振ECL的纳米结构膜。研究纳米簇尺寸、铁磁层厚度、纳米板层数以及纳米材料形状尺寸对偏振度的影响，建立相应的物理模型，揭示偏振ECL产生的机制。将具有最大偏振度的纳米结构ECL发射膜用于生物靶标的分析及生命物质的结构变化研究。本项目的成功实施将为ECL的偏振调制及了解生物物质结构、性质的改变与疾病的关系提供理论依据。

在电致化学发光（ECL）体系中引入偏振这个维度特别是外场如电场和磁场可调控的偏振性将极大地扩展ECL技术的应用范围，但是如何实现仍然具有挑战性。本项目设计制备了形貌各向异性的CdS纳米棒、TiO2纳米管和针尖状NiCo2S4-xPx纳米线，磁阻各向异性的NaFeS2纳米管及本征结构各向异性的ReS2纳米片等多个纳米结构，表征了这些材料的物理性质和ECL性能，研究了各向异性激子产生偏振ECL的条件及外加磁场和电场对各向异性激子的调控可能性，探索了磁场调控ECL偏振性的物理机制。结果显示，轴径比为25且具有ECL活性的CdS纳米棒即使无序堆积也可产生各向异性的激子进而实现偏振ECL，偏振光含量可达70%。将形貌各向异性的TiO2纳米管有序排列，可将偏振ECL光含量提至80%。在固定偏振角度的情况下，该偏振ECL可无标记检测具有旋光性的手性分子。以L-半胱胺酸和D-葡萄糖为模型靶标，TiO2纳米管阵列的偏振ECL对L-半胱氨酸和D-葡萄糖的检测限分别为1 nM和10 nM。当纳米棒轴径比增大形成纳米线时，ECL发射效率将大幅降低，逐渐具有电催化能力。由于针尖诱导效应，针尖状NiCo2S4-xPx纳米线阵列能催化电解水产氢及[Ru(bpy)3]2+的阴极ECL，将发光起置电势大幅度正移至-0.6 V，发光峰位仅为-0.8 V。而磁阻各向异性的NaFeS2纳米管不但能催化增强3倍的[Ru(bpy)3]2+阴极ECL，且2.4 Gs的超低外磁场就可诱导产生偏振ECL，偏振光含量达70%。这种低外磁场诱导的偏振ECL源于NaFeS2纳米管各向异性的磁化行为，即ECL偏振方向沿着磁电阻最小的方向。此外，引入S空位的ReS2纳米片也可产生缺陷相关的各向异性激子发射（偏振光致发光），方向沿Re-S原子链。重要的是，此偏振光致发光可受外加电场灵敏调控。本项目的研究结果对纳米结构膜中实现偏振ECL调制具有指导意义，同时开辟了局域电场调节ECL性能的新技术，为基于偏振ECL的传感器设计提供了新思路，扩展了ECL技术在能源领域的应用。