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，比如右手和左手，还是微观的，比如分子。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，手性在纳米尺度上，尤其是纳米颗粒上，仍未得到充分的研究。理解和控制纳米颗粒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。本研究的目标是发现和研究制备手性纳米粒子的有效途径。实现对纳米颗粒手性的控制，并将其与纳米颗粒尺寸、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基石。最近，我的实验室生产出了具有明显手性和胶体稳定性的金纳米颗粒。在我们目前的研究阶段，手性纳米颗粒形成的机制将被详细研究。大多数纳米颗粒显示出与尺寸相关的光学特性（“量子尺寸”效应），因此拉曼和紫外可见显微光谱的结合将用于纳米颗粒形成的敏感原位监测。我们还将探索手性纳米粒子的自组装及其与合适基质的结合，以生产具有可控手性和纳米级结构的新型复合材料。这类材料在高级光学应用中很有前途，例如超材料。具有可控手性、表面功能性和选择性光学响应的材料是生物传感器的自然选择。由于纳米粒子的特性比块状材料对表面变化更敏感，因此它们可以被定制来检测非常少量的目标分子。手性纳米颗粒在对映选择性催化中具有优势，目前的重点是有效地合成与天然化合物相似的分子。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.