Mir Irshad Ahmad, Das Kishan, Akhter Tabasum, Ranjan Rahul, Patel Rajan, Bohidar H B
School of Physical Sciences, Jawaharlal Nehru University New Delhi India
Department of Botany, University of Delhi New Delhi India.
RSC Adv. 2018 Aug 30;8(53):30589-30599. doi: 10.1039/c8ra04866e. eCollection 2018 Aug 24.
We report on the green and facile aqueous microwave synthesis of glutathione (GSH) stabilized luminescent CuInS (CIS, size = 2.9 nm) and CuInS@ZnS core-shell (CIS@ZnS, size = 3.5 nm) quantum dots (QDs). The core-shell nanostructures exhibited excellent photo- and water/buffer stability, a long photoluminescence (PL) lifetime (463 ns) and high PL quantum yield (PLQY = 26%). We have evaluated the comparative enzyme kinetics of these hydrophilic QDs by interacting them with the model enzyme lysozyme, which was probed by static and synchronous fluorescence spectroscopy. The quantification of the QD-lysozyme binding isotherm, exchange rate, and critical flocculation concentration was carried out. The core-shell QDs exhibited higher binding with lysozyme yielding a binding constant of = 5.04 × 10 L mol compared to the core-only structures ( = 6.16 × 10 L mol), and the main cause of binding was identified as being due to hydrophobic forces. In addition to the enzyme activity being dose dependent, it was also found that core-shell structures caused an enhancement in activity. Since binary QDs like CdSe also show a change in the lysozyme enzyme activity, therefore, a clear differential between binary and ternary QDs was required to be established which clearly revealed the relevance of surface chemistry on the QD-lysozyme interaction.
我们报道了通过绿色且简便的水相微波合成法制备谷胱甘肽（GSH）稳定的发光铜铟硫（CIS，尺寸 = 2.9 nm）和铜铟硫@硫化锌核壳（CIS@ZnS，尺寸 = 3.5 nm）量子点（QDs）。核壳纳米结构表现出优异的光稳定性和水/缓冲液稳定性、较长的光致发光（PL）寿命（463 ns）以及较高的PL量子产率（PLQY = 26%）。我们通过将这些亲水性量子点与模型酶溶菌酶相互作用，利用静态和同步荧光光谱对其比较酶动力学进行了评估。对量子点 - 溶菌酶结合等温线、交换速率和临界絮凝浓度进行了定量分析。与仅含核心的结构（ = 6.16 × 10 L mol）相比，核壳量子点与溶菌酶表现出更高的结合力，结合常数为 = 5.04 × 10 L mol，并且确定结合的主要原因是由于疏水力。除了酶活性呈剂量依赖性外，还发现核壳结构导致活性增强。由于二元量子点如硒化镉也显示出溶菌酶活性的变化，因此，需要明确二元和三元量子点之间的差异，这清楚地揭示了表面化学在量子点 - 溶菌酶相互作用中的相关性。
