EAGER: New Ligand Shells for Small Quantum Dots

智力上的优点。当用报告标签标记蛋白质以追踪蛋白质在细胞上或细胞内的位置和运动时，标签的物理尺寸可能相当大。对于被称为量子点(Qdots)的流行标签来说尤其如此，这是一种具有强烈荧光的无机晶体。量子点的核心相当小，只有2-4 nm，但完全不溶。要使它们在水基缓冲液中溶解，需要一个疏水-亲水的配位体壳层。商业上可获得的量子点的直径通常为21 nm。这项研究将制造一种只有2纳米厚的配基屏蔽。屏蔽层将有一个硫原子，它与量子点核心紧密结合。这种硫要么是硫醇，要么是硫醚，要么是硫酮。这种硫磺还将含有聚乙二醇，使该实体可溶于水。它可能带有负电荷或正电荷，以减少非特异性粘连。最后，它将有一个用于偶联的生物活性实体。量子点具有巨大的潜力，可以作为令人难以置信的明亮的荧光团来标记蛋白质。然而，它们的巨大体积限制了它们作为生物示踪剂的用途。这项研究旨在通过向研究界提供方法来制造一种新的水溶性量子点，这种量子点比目前商业上可用的量子点小得多，从而克服了这一限制。这项研究为对基础光学、显微镜和光谱学感兴趣的合成化学家和研究生提供了极好的培训。

Intellectual merit. When proteins are tagged with reporter labels to trace the locations and movements of the proteins on or within cells, the physical size of the label can be quite significant. This is especially true for the popular class of labels called quantum dots (qdots), which are inorganic crystals with intense fluorescence. The core of a qdot is fairly small, 2-4 nm, but is completely insoluble. To make them soluble in water-based buffers requires a hydrophobic-hydrophilic ligand shell. Commercially-available qdots are typically 21 nm in diameter. The research will make a ligand-shield that is only about 2 nm thick. The shield will have a sulfur atom that binds the qdot-core very tightly. This sulfur will either be a thiol, a thioether, or a thioketone. This sulfur will also have a polyethylene glycol, making the entity water soluble. It may have a negative or positive charge to reduce non-specific sticking. Finally, it will have a bioreactive entity for coupling.Broader Impacts. Quantum dots have tremendous potential as incredibly bright fluorophores for labeling proteins. However, their large size has limited their usefulness as biological tracers. The research presented here intends to overcome this limitation by providing to the research community methods to make a new class of water-soluble quantum dots that are significantly smaller than those currently commercially available. The research provides excellent training for synthetic chemists and graduate students who are interested in basic optics, microscopy, and spectroscopy.