Design and characterization of lysine cross-linked mereapto-acid biocompatible quantum dots
Design and characterization of lysine cross-linked mereapto-acid biocompatible quantum dots
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DOI：
10.1021/cm051393
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发表时间：
2006-02-21
影响因子：
8.6
通讯作者：
Chan, WCW
中科院分区：
文献类型：
--
作者：
Jiang, W;Mardyani, S;Chan, WCW
半导体量子点（QDs）是新一代无机探针，在生物应用方面具有传统有机探针无法比拟的优势。在生物学中使用量子点的一个主要障碍是疏水合成的量子点无法与水环境界面。疏水量子点的表面改性已经取得了巨大的进展。然而，目前的技术都不符合理想的生物应用量子点涂层的所有标准（例如，保持量子点的小尺寸和光学性质，具有低非特异性结合），同时提供成本效益，易于大规模制备。我们开发了一种高度稳定的生物相容性涂层，用于zns覆盖的CdSe量子点表面，该涂层保持了所有疏水涂层量子点的光学特性。首先用巯基十四酸包覆这些量子点，然后在双环己基碳二亚胺的存在下与赖氨酸交联，形成稳定的亲水壳。表面含有羧酸和氨基官能团，可与生物分子偶联。利用动态光散射方法，我们发现这些表面修饰的量子点的水动力直径约为20 nm。我们证明了制备bb0 400mg生物相容性量子点的可行性，并成功地将蛋白质偶联到它们的表面。最后，我们表征了量子点在各种生物相关环境下的稳定性和光学特性。
Semiconductor quantum dots (QDs) are a new generation of inorganic probes with advantageous properties over traditional organic-only probes for biological applications. A major hurdle in the use of QDs for biology is the inability of the hydrophobically synthesized QDs to interface with aqueous environments. There have been tremendous advances in the surface modification of hydrophobic QDs. However, none of the current techniques fits all of the criteria for an ideal QD coating for biological applications (e.g., maintain the small size and optical properties of QDs, have low nonspecific binding) while providing cost-effective, easy preparation on a large scale. We developed a highly stable biocompatible coating for the surface of ZnS-capped CdSe QDs that maintains all of the hydrophobic-coated QD optical properties. These QDs are prepared by first coating them with mercaptoundecanoic acid and are further cross-linked with the amino acid lysine in the presence of dicyclohexylcarbodiimide to form a stable hydrophilic shell. The surface contains carboxylic acid and amino functional groups for conjugation to biomolecules. Using a dynamic light scattering method, we found that the hydrodynamic diameter of these surface-modified QDs is approximately 20 nm. We demonstrated the feasibility of preparing > 400 mg of the biocompatible QDs and the successful conjugation of proteins onto their surface. Finally, we characterized the QD stability and optical properties in various biologically relevant environments.