Surface-enhanced spectroscopy, nanostructure fabrication and sensor applications

分子是我们呼吸、喝或吃的所有东西的组成部分。然而，直到最近，单个分子的检测更多的是虚构而不是科学。目前的方案是利用金属纳米粒子作为发射器接收来自单个分子的指纹信号。单分子的检测是用银和金的金属纳米结构实现的，并且大量的努力致力于这种结构的制造和它们的光学性质的研究。因此，该项目的第一步是制造用于检测分子种类的银或金纳米结构（大约比正在研究的分子大100倍）。此外，如果我们能检测到一个，就很容易检测到一堆，我们正在开发分析方案，用同样的方法检测非常少量的分子。后者被称为痕量分析，可以检测环境中的少量污染物，药物化学品中的污染物，或检测微生物和毒素。痕量分析的应用潜力是如此明显，以至于为特定检测系统申请专利的竞赛正在进行，许多小公司正在从痕量分析中蓬勃发展。在本研究计划中，我们探索了两种可以使用金属纳米结构提供单分子检测（SMD）的技术；它们是表面增强拉曼散射（SERS）和表面增强荧光（SEF）。我们希望为SMD提供模式识别。因此，当单个分子发出有关其环境或环境变化的信息时，可以给出适当的解释。开发SMD方法相当于为生物，化学和物理科学的应用寻找最终的传感器元件。这就解释了人们对探测来自单个分子的信号的巨大兴趣。

Molecules are the building blocks of everything we breathe, drink or eat. However, until very recently, the detection of a single molecule was more fiction than science. The present proposal is about receiving the fingerprint signals from a single molecule using metal nanoparticles as transmitters. The detection of single molecules is achieved with metallic nanostructures of silver and gold, and a great deal of effort is dedicated to the fabrication of such structures and to the study of their optical properties. Thus, the first step in this project is the fabrication of silver or gold nanostructures (about 100 times bigger than the molecule under investigation) used in the detection of molecular species. In addition, if we can detect one, it would be easy to detect a bunch of them and we are developing analytical protocols to detect very small amounts of molecules using the same method. The latter is known as trace analysis, and can involve the detection of small amounts of pollutants in the environment, contaminants in pharmochemicals, or the detection of micro-organisms and toxins. The potential for applications is so evident that the race for patenting specific detection systems is on, and many small companies are flourishing profiting from trace analysis. In this research proposal we explore two techniques that can provide single molecule detection (SMD) using metallic nanostructures; they are surface-enhanced Raman scattering (SERS) and surface-enhanced fluorescence (SEF). We hope to provide pattern recognition for SMD. Therefore, when a single molecule send out information about its environment, or changes in it, a proper interpretation can be given. Developing the methods for SMD is equivalent to finding the ultimate sensor element for applications in biological, chemical and physical sciences. This explains the enormous interest in detecting the signal coming from a single molecule.