Faculty of Chemistry , University of Wrocław , ul. F. Joliot-Curie 14 , 50-383 Wrocław , Poland.
Institute of Immunology and Experimental Therapy , Polish Academy of Sciences , ul. R. Weigla 12 , 53-114 Wrocław , Poland.
Langmuir. 2019 Apr 23;35(16):5509-5516. doi: 10.1021/acs.langmuir.8b04221. Epub 2019 Apr 15.
In this paper, we report a reliable method for transferring hydrophobic, NIR-emitting PbS/CdS core-shell quantum dots (QDs) to water solutions using synthesized in situ dithiocarbamate derivatives of amino acids as stabilizing ligands. Such ligands offer apparent advantages over dihydrolipoic acid (DHLA) derivatives commonly used as ligands stabilizing quantum dots. The most effective phase transfer and the best long-term stability of water dispersions of amino acid-DTC-capped QDs were achieved using lysine dithiocarbamate. In this case, the phase transfer of PbS/CdS nanoparticles from organic to aqueous phase can be completed in 6-8 h. Prepared amino acid-DTC-capped QDs nanoparticles have narrow size distributions, and their hydrodynamic diameter remains below 9 nm. After transferring to water, lysine-DTC-capped PbS/CdS nanoparticles retain their spectroscopic properties for at least 48 h. Moreover, they are not toxic up to concentration corresponding to about 7 μg/cm of PbS/CdS, which is sufficient for their application in biological systems. In addition, lysine-DTC-capped PbS/CdS QDs can be straightforwardly modified by layer-by-layer polyelectrolyte coating.
在本文中，我们报告了一种可靠的方法，用于使用合成的原位氨基酸二硫代氨基甲酸盐衍生物将疏水性近红外发射 PbS/CdS 核壳量子点 (QD) 转移到水溶液中。与通常用作稳定量子点的配体的二氢硫辛酸 (DHLA) 衍生物相比，这些配体具有明显的优势。使用赖氨酸二硫代氨基甲酸盐，实现了氨基酸-DTC 封端的 QD 的最有效的相转移和最佳的长期水分散体稳定性。在这种情况下，PbS/CdS 纳米粒子从有机相到水相的相转移可以在 6-8 小时内完成。制备的氨基酸-DTC 封端的 QD 纳米粒子具有窄的尺寸分布，其水动力直径保持在 9nm 以下。转移到水后，赖氨酸-DTC 封端的 PbS/CdS 纳米粒子至少在 48 小时内保留其光谱特性。此外，它们的毒性在浓度对应于约 7μg/cm 的 PbS/CdS 时不高，这足以满足它们在生物系统中的应用。此外，赖氨酸-DTC 封端的 PbS/CdS QD 可以通过层层聚电解质涂层直接进行修饰。
