Chiral nanoparticles: preparation and studies of their optical properties and self-assembly into functional nanocomposite materials

手性是所有物体的固有属性，无论是宏观的，如右手和左手的，还是微观的，如分子。手性在化学中非常重要，因为大多数天然分子都是手性的。然而，手性仍然在很大程度上没有在纳米尺度上被探索，特别是对于纳米粒子。了解和控制纳米粒子的手性是至关重要的，并将直接影响手性材料在催化和生物传感器中的应用。这项研究的目的是发现和研究制备手性纳米粒子的有效途径。实现对纳米粒子手性的控制，并将其与对纳米粒子的尺寸、多分散性和表面功能的控制相结合，将使其成为具有可调功能特性的纳米复合材料的手性构建块。最近，我的实验室已经生产出了具有显著手性和胶体稳定性的金纳米颗粒。在我们目前的研究阶段，手性纳米粒子的形成机理还有待于详细的研究。大多数纳米粒子表现出与尺寸相关的光学性质(量子尺寸效应)，因此拉曼光谱和紫外可见光谱的结合将被用于灵敏的原位监测纳米粒子的形成。我们还将探索手性纳米颗粒的自组装及其在合适的基质中的结合，以制备具有可控手性和纳米结构的新型复合材料。这类材料在先进的光学应用中很有前途，例如超材料。具有可控手性、表面功能和选择性光学响应的材料是生物传感器的自然选择。它们可以被量身定做来检测非常少量的目标分子，因为与块状材料相比，纳米粒子的性质对表面变化更敏感。手性纳米粒子在对映体选择性催化方面具有优势，目前的研究方向是高效合成类似天然化合物的分子。因此，我们的研究方向将是生产用于催化剂和传感器的纳米复合材料。

Chirality is an inherent property of all objects, be they macroscopic, such as right and left hands, or microscopic, like molecules. Chirality is very important in chemistry since most natural molecules are chiral. Yet, chirality still remains largely underexplored at the nanoscale, and especially for nanoparticles. Understanding and controlling nanoparticle chirality is of fundamental importance and will immediately impact applications of chiral materials in catalysis and biosensors. The aspiration of the proposed research is to discover and study efficient routes of preparation of chiral nanoparticles. Attaining control over nanoparticle chirality and combining it with control over size, polydispersity and surface functionalities of nanoparticles will enable their applications as chiral building blocks for nanocomposite materials with tunable functional properties. Recently, gold nanoparticles featuring prominent chirality and colloidal stability have been produced in my laboratory. At the current stage of our research, the mechanisms of chiral nanoparticle formation are to be investigated in detail. Most nanoparticles display size-dependent optical properties ("quantum size" effect), so the combination of Raman and UV-Vis microspectroscopy will be used for sensitive in-situ monitoring of nanoparticle formation. We will also explore self-assembly of chiral nanoparticles and their incorporation into suitable matrices to produce novel composite materials with controlled chirality and nanoscale architecture. Such materials are promising in advanced optical applications, e.g. metamaterials.  Materials with controlled chirality, surface functionality and selective optical responses are a natural choice for biosensors. They can be tailored to detect a very small number of target molecules, since nanoparticle properties are much more sensitive to surface changes compared to bulk materials. Chiral nanoparticles are advantageous for enantioselective catalysis, where the current thrust is to efficiently synthesize molecules similar to natural compounds. Accordingly, our research will be directed to produce nanocomposite materials for catalysts and sensors.