Detection, identification and characterization of single nanoparticles based on plamonic visualization of their electrochemical dissolution

目前还缺乏用于纳米颗粒常规分析的高灵敏分析技术。与此同时，不断增加的工业生产和纳米颗粒的应用增加了人类接触这些潜在危险材料的风险。该项目的目标是开发一种高灵敏度的分析方法，用于检测、表征和鉴定液体介质中的纳米颗粒。纳米颗粒的检测将使用广域表面等离子显微镜--这项技术允许人们检测吸附在黄金表面的单个纳米颗粒。测量是在宏观尺寸的电极上进行的，这提供了高灵敏度(低于每微米L 100个纳米颗粒)、高动态范围(分别检测和分析多达数十万个纳米颗粒)以及进行可靠的统计分析的可能性。纳米粒子的光信号与其大小和组成的依赖关系为研究每个单独的纳米粒子的电化学行为提供了可能性，而不需要直接测量电流。根据纳米颗粒的类型，将分析它们的电化学转化或电催化活性。例如，被吸附的纳米颗粒的电化学溶解，当其图像(由表面等离子显微镜获得)在施加到金层的规定的电势下消失时被检测到，它提供了关于每个被吸附的纳米颗粒的化学成分的信息。溶解电势相对于其热力学数值的微小移动提供了有关纳米颗粒大小的信息。纳米颗粒电化学转化的动力学限制有望提供有关纳米颗粒介电涂层厚度的信息。该提案的第一个工作包侧重于优化实验条件，以快速和完全地电化学溶解可能范围广泛的金属纳米颗粒。结果将用于第二个工作包，重点是使用表面等离子体显微镜研究这些过程。对成千上万个纳米粒子中的每一个同时发生电化学反应的光学数据的高通量分析需要开发和编程用于图像分析的复杂算法，这是第三个工作包的主要目标。在第四个工作包中，结果将扩展到实际相关的氧化物纳米颗粒，非水电解液将用于扩展电位窗口。最后(第五个工作包)，该方法将用于分析含有不同组成、大小和形状的纳米颗粒的多组分体系，以及复杂介质中含有纳米颗粒的实际样品的分析。

There is still a lack of highly sensitive analytical technique for routine analysis of nanoparticles. In the same time, a permanently increasing industrial production and application of nanoparticles increase a risk of human exposure to these potentially hazardous materials. The goal of the project is the development of a highly sensitive analytical method for detection, characterization and identification of nanoparticles in liquid media. The detection of nanoparticles will be performed using wide field surface plasmon microscopy - this technology allows one to detect single nanoparticles adsorbed on the gold surface. The measurements are performed on the electrodes of macroscopic size, this provides high sensitivity (below 100 nanoparticles per µL), high dynamic range (each nanoparticle from up to hundreds thousands is detected and analyzed individually) and the possibility to make reliable statistical analysis. Dependence of optical signals of nanoparticles on their size and composition provides a possibility to study electrochemical behavior of each individual nanoparticle without direct measurements of electrical current. Depending on the type of nanoparticles, their electrochemical conversions or electrocatalytical activity will be analyzed. For example, electrochemical dissolution of adsorbed nanoparticles, detected as the disappearance of their images (obtained by surface plasmon microscopy) at defined electrical potential applied to the gold layer, gives information on the chemical composition of each adsorbed nanoparticle. A small shift of the dissolution potential relative its thermodynamic value provides information on the size of nanoparticle. Kinetic limitations of electrochemical conversions of nanoparticles are expected to give information on the thickness of dielectric coating of nanoparticles. The first work package of the proposal is focused on optimization of experimental conditions for fast and complete electrochemical dissolution of a possibly wide range of metal nanoparticles. The results will be used in the second work package focused on the investigation of these processes using surface plasmon microscopy. High throughput analysis of optical data characterizing simultaneous electrochemical reactions on each from many thousands of nanoparticles requires a development and programming of sophisticated algorithms for image analysis, this is the main goal of the third work package. In the fourth work package the results will be extended to practically relevant oxide nanoparticles, non-aqueous electrolytes will be used to extend potential window. Finally (the fifth work package), the method will be applied for analysis of multicomponent systems containing nanoparticles of various composition, size and shape and for analysis of real samples containing nanoparticles in complex media.