Analytical & Testing Center and Key Laboratory of Green Chemistry and Technology of MOE in College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, PR China.
Chemistry. 2013 Jun 3;19(23):7473-9. doi: 10.1002/chem.201204035. Epub 2013 Apr 10.
Proteins typically have nanoscale dimensions and multiple binding sites with inorganic ions, which facilitates the templated synthesis of nanoparticles to yield nanoparticle-protein hybrids with tailored functionality, water solubility, and tunable frameworks with well-defined structure. In this work, we report a protein-templated synthesis of Mn-doped ZnS quantum dots (QDs) by exploring bovine serum albumin (BSA) as the template. The obtained Mn-doped ZnS QDs give phosphorescence emission centered at 590 nm, with a decay time of about 1.9 ms. A dual-channel sensing system for two different proteins was developed through integration of the optical responses (phosphorescence emission and resonant light scattering (RLS)) of Mn-doped ZnS QDs and recognition of them by surface BSA phosphorescent sensing of trypsin and RLS sensing of lysozyme. Trypsin can digest BSA and remove BSA from the surface of Mn-doped ZnS QDs, thus quenching the phosphorescence of QDs, whereas lysozyme can assemble with BSA to lead to aggregation of QDs and enhanced RLS intensity. The detection limits for trypsin and lysozyme were 40 and 3 nM, respectively. The selectivity of the respective channel for trypsin and lysozyme was evaluated with a series of other proteins. Unlike other protein sensors based on nanobioconjugates, the proposed dual-channel sensor employs only one type of QDs but can detect two different proteins. Further, we found the RLS of QDs can also be useful for studying the BSA-lysozyme binding stoichiometry, which has not been reported in the literature. These successful biosensor applications clearly demonstrate that BSA not only serves as a template for growth of Mn-doped ZnS QDs, but also impacts the QDs for selective recognition of analyte proteins.
蛋白质通常具有纳米级尺寸和多个与无机离子的结合位点，这有利于模板合成纳米粒子，从而得到具有定制功能、水溶性和可调框架的纳米粒子-蛋白质杂化物，且具有明确的结构。在这项工作中，我们通过探索牛血清白蛋白（BSA）作为模板，报告了一种蛋白质模板合成 Mn 掺杂的 ZnS 量子点（QD）的方法。所得的 Mn 掺杂的 ZnS QD 发出以 590nm 为中心的磷光发射，衰减时间约为 1.9ms。通过将 Mn 掺杂的 ZnS QD 的光学响应（磷光发射和共振光散射（RLS））与它们的表面 BSA 磷光传感识别的胰蛋白酶和 RLS 传感识别的溶菌酶的光学响应进行集成，开发了用于两种不同蛋白质的双通道传感系统。胰蛋白酶可以消化 BSA 并从 Mn 掺杂的 ZnS QD 的表面去除 BSA，从而猝灭 QD 的磷光，而溶菌酶可以与 BSA 组装导致 QD 聚集和增强 RLS 强度。胰蛋白酶和溶菌酶的检测限分别为 40 和 3nm。用一系列其他蛋白质评估了各自通道对胰蛋白酶和溶菌酶的选择性。与基于纳米生物共轭物的其他蛋白质传感器不同，所提出的双通道传感器仅使用一种类型的 QD，但可以检测两种不同的蛋白质。此外，我们发现 QD 的 RLS 也可用于研究 BSA-溶菌酶结合化学计量比，这在文献中尚未报道过。这些成功的生物传感器应用清楚地表明，BSA 不仅作为 Mn 掺杂的 ZnS QD 的生长模板，而且还影响 QD 对分析物蛋白质的选择性识别。
