School of Environmental Science and Engineering, China-America CRC for Environment & Health, Shandong University, Shandong Province, Jinan, People's Republic of China.
Biol Trace Elem Res. 2013 Oct;155(1):150-8. doi: 10.1007/s12011-013-9771-z. Epub 2013 Aug 1.
Quantum dots (QDs) are recognized as some of the most promising candidates for future applications in biomedicine. However, concerns about their safety have delayed their widespread application. Human serum albumin (HSA) is the main protein component of the circulatory system. It is important to explore the interaction of QDs with HSA for the potential in vivo application of QDs. Herein, using spectroscopy and isothermal titration calorimetry (ITC), the effect of glutathione-capped CdTe quantum dots of different sizes on the HSA was investigated. After correction for the inner filter effect, the fluorescence emission spectra and synchronous fluorescence spectra showed that the microenvironment of aromatic acid residues in the protein was slightly changed when the glutathione (GSH)-cadmium telluride (CdTe) QDs was added, and GSH-CdTe QDs with larger particle size exhibited a much higher effect on HSA than the small particles. Although a ground-state complex between HSA and GSH-CdTe QDs was formed, the UV-vis absorption and circular dichroism spectroscopic results did not find appreciable conformational changes of HSA. ITC has been used for the first time to characterize the binding of QDs with HSA. The ITC results revealed that the binding was a thermodynamically spontaneous process mainly driven by hydrophobic interactions, and the binding constant tended to increase as the GSH-CdTe QDs size increased. These findings are helpful in understanding the bioactivities of QDs in vivo and can be used to assist in the design of biocompatible and stable QDs.
量子点 (QDs) 被认为是未来在生物医学中应用最有前途的候选者之一。然而，对其安全性的担忧延迟了它们的广泛应用。人血清白蛋白 (HSA) 是循环系统的主要蛋白质成分。探索 QDs 与 HSA 的相互作用对于 QDs 的潜在体内应用非常重要。在此，使用光谱法和等温滴定量热法 (ITC) 研究了不同尺寸的谷胱甘肽包覆的 CdTe 量子点对 HSA 的影响。在修正内滤效应后，荧光发射光谱和同步荧光光谱表明，当加入谷胱甘肽 (GSH)-碲化镉 (CdTe) QDs 时，蛋白质中芳香族氨基酸残基的微环境略有变化，并且较大粒径的 GSH-CdTe QDs 对 HSA 的影响比小颗粒高得多。尽管形成了 HSA 与 GSH-CdTe QDs 的基态复合物，但紫外-可见吸收和圆二色性光谱结果并未发现 HSA 的明显构象变化。首次使用 ITC 来表征 QDs 与 HSA 的结合。ITC 结果表明，结合是一个热力学自发过程，主要由疏水相互作用驱动，并且结合常数随着 GSH-CdTe QDs 尺寸的增加而趋于增加。这些发现有助于理解 QDs 在体内的生物活性，并可用于辅助设计生物相容性和稳定的 QDs。
