Department of Chemistry and Biochemistry, The University of Southern Mississippi, Hattiesburg, MS 39406, USA.
Phys Chem Chem Phys. 2010 Sep 14;12(34):10073-80. doi: 10.1039/c0cp00545b. Epub 2010 Aug 4.
Electrogenerated chemiluminescence (ECL) of water-soluble core/shell CdSe/ZnS quantum dots (QDs) coated with carboxylated polyethylene glycol polymers ("Qdot 625") was investigated in aqueous solutions using 2-(dibutylamino)ethanol (DBAE) and tri-n-propylamine (TPrA) as ECL coreactants. In both cases, ECL emissions at glassy carbon (GC) electrode appeared at the same potential of approximately 0.80 V vs. Ag/AgCl (3.0 M KCl), which was approximately 200 and approximately 150 mV more positive compared with the oxidation potentials for DBAE (approximately +0.60 V vs. Ag/AgCl) and TPrA (approximately +0.65 V vs. Ag/AgCl), respectively. The ECL intensity, however, was significantly affected by the type and the concentration of the ECL coreactant used as well as the nature of the working electrode. Under the present experimental conditions, ECL from DBAE was approximately 17 times stronger than that from TPrA. The maximum ECL was obtained at GC electrode when [DBAE] approximately = 53 mM, where a ratio of 11:3:1 in ECL intensity was evaluated for GC, Au, and Pt electrodes, respectively. The ECL emission of the Qdot 625/DBAE system had an apparent peak value of approximately 625 nm that matched well the fluorescence data. The QD as a label for ECL-based immunoassays of C-reactive protein (CRP) was realized by covalent binding of avidin on its surface, which allowed biotinylated anti-CRP to be attached and interacted with solution-phase CRP and the anti-CRP linked to micro-sized magnetic beads. The newly formed sandwich type aggregates were separated magnetically from the solution matrix, followed by the ECL generation at partially transparent Au nanoparticle-coated ITO electrode or Au/CD electrode in the presence of DBAE. Much stronger ECL responses were observed from the Au/CD electrode, at which a dynamic range of 1.0-10.0 microg mL(-1) CRP and a limit of detection of 1.0 microg mL(-1) CRP were obtained, respectively.
水溶性核壳型 CdSe/ZnS 量子点（QD）表面包裹聚羧酸乙二醇聚合物（“Qdot 625”）的电致化学发光（ECL）在水溶液中使用 2-(二丁氨基)乙醇（DBAE）和三正丙胺（TPrA）作为 ECL 共反应物进行了研究。在这两种情况下，玻璃碳（GC）电极上的 ECL 发射均出现在约 0.80 V 相对于 Ag/AgCl（3.0 M KCl）的相同电势，与 DBAE（约 +0.60 V 相对于 Ag/AgCl）和 TPrA（约 +0.65 V 相对于 Ag/AgCl）的氧化电势相比，分别正约 200 和约 150 mV。然而，ECL 强度受到所使用的 ECL 共反应物的类型和浓度以及工作电极的性质的显著影响。在本实验条件下，DBAE 的 ECL 强度比 TPrA 强约 17 倍。当 [DBAE]约= 53 mM 时，在 GC 电极上获得最大 ECL，其中分别评估 GC、Au 和 Pt 电极的 ECL 强度比为 11:3:1。Qdot 625/DBAE 体系的 ECL 发射具有约 625nm 的明显峰值，与荧光数据吻合良好。通过在其表面共价结合亲和素，将 QD 用作基于 ECL 的 C-反应蛋白（CRP）免疫测定的标记物，允许生物素化的抗 CRP 与之结合并与溶液相 CRP 相互作用，并且与微尺寸的磁性珠连接。新形成的夹心型聚集体通过磁场从溶液基质中分离出来，然后在存在 DBAE 的情况下，在部分透明的 Au 纳米粒子涂覆的 ITO 电极或 Au/CD 电极上产生 ECL。从 Au/CD 电极观察到更强的 ECL 响应，在该电极上获得了 1.0-10.0μgmL（-1）CRP 的动态范围和 1.0μgmL（-1）CRP 的检测限。
