Semiconductor Nanocrystals for Biomedical Imaging

第一阶段的主要目标是展示用于细胞成像的发光纳米颗粒(量子点，量子点)的稳定化和功能化的方法。这将通过将量子点封装在两种不同类型的水溶性聚合物输送载体中来实现。这两种类型的聚合物最终都将通过特定的靶向配体进行功能化，以便于对选定的细胞靶标进行成像。使量子点非常适合这种成像应用的物理化学性质包括：它们的量子产率、小尺寸、发射波长窄，对多个尺寸的QD标签之间的光谱重叠影响很小或没有影响，它们的光稳定性，以及它们非常高的吸收效率，从而消除了激发所需的高功率要求。在第一阶段，我们将合成聚合物，并使用它们来包裹定义直径的量子点。每个纳米颗粒复合体将根据发光曲线、量子产率、光稳定性和消光系数进行表征。这些性质将在各种环境中进行检查，以确定荧光行为的任何与pH或溶剂相关的方面。这两种类型的包裹纳米颗粒探针将被用来转染培养的哺乳动物细胞，以评估生理环境中的量子点发光。

The principal objective in Phase I is to demonstrate methodologies for the stabilization and functionalization of luminescent nanoparticles (quantum dots, QDs) to be used in cellular imaging. This will be achieved by encapsulating QDs in two different types of water-soluble polymer delivery vehicles. Both types of polymer will eventually be functionalized with specific targeting ligands in order to facilitate imaging of selected cellular targets. The physicochemical properties that make QDs well suited for such imaging applications include: their quantum yields, small size, narrow emission wavelengths which effect little or no spectral overlap among multiple-size QD tags, their photostability, and their very high absorption efficiencies which obviate the need for high power requirements for excitation. In Phase I, we will synthesize the polymers and use them to encapsulate QDs of defined diameter. Each nanoparticle complex will be characterized in terms of luminescence profile, quantum yield, photostability, and extinction coefficient. These properties will be examined in a variety of environments to determine any pH- or solvent dependent aspects of fluorescence behavior. Both types of encapsulated nanoparticle probes will be used to transfect cultured mammalian cells in order to assess QD luminescence in a physiological milieu.