Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-sen University, Kaohsiung 804, Taiwan.
Analyst. 2012 Nov 21;137(22):5352-7. doi: 10.1039/c2an35586h.
This study develops a novel and high performance colorimetric probe for dopamine (DA) detection. Aqueous-phase gold nanoparticles (AuNPs) extracted with 4-(dimethylamino)pyridine (DMAP) from toluene solvent are used as the reaction probes. The original AuNPs of diameter around 13 nm separate into 2-5 nm sizes when dopamine (DA) is added, resulting in the color change of the AuNP solution from red to blackish green. Transmission electron microscopy (TEM) observations and dynamic light scattering (DLS) tests show that the AuNPs break into their smaller sizes right after addition of DA. The results confirm that the DMAP capped AuNPs are etched by the DA molecules due to the strong affinity between DA and AuNPs, thus causing a blue shift in the absorption spectrum. The concentration of DA is quantitatively monitored by using a UV-Vis spectrometer with a limit of detection (LOD) as low as 5 nM. In addition, the results also show that the methods developed appear to have no significant problems in detecting DA in the sample even with the presence of (10 mM) common interferents such as ascorbic acid (AA), homovanillic acid (HVA), catechol (CA) and glutathione (GSH). The developed AuNP etching protocol for dopamine detection provides a novel and versatile approach for rapid biosensing applications.
本研究开发了一种用于多巴胺（DA）检测的新型高性能比色探针。从甲苯溶剂中用 4-（二甲氨基）吡啶（DMAP）提取的水相金纳米粒子（AuNP）用作反应探针。当加入多巴胺（DA）时，直径约为 13nm 的原始 AuNP 分离成 2-5nm 大小，导致 AuNP 溶液的颜色从红色变为深绿色。透射电子显微镜（TEM）观察和动态光散射（DLS）测试表明，DA 加入后，AuNP 立即分解成较小的尺寸。结果证实，由于 DA 与 AuNP 之间的强亲和力，DMAP 封端的 AuNP 被 DA 分子蚀刻，从而导致吸收光谱发生蓝移。使用紫外-可见分光光度计定量监测 DA 的浓度，检测限（LOD）低至 5 nM。此外，结果还表明，即使存在（10mM）常见干扰物，如抗坏血酸（AA）、高香草酸（HVA）、儿茶酚（CA）和谷胱甘肽（GSH），开发的方法在检测样品中的 DA 时似乎也没有明显的问题。用于多巴胺检测的 AuNP 蚀刻方案为快速生物传感应用提供了一种新颖而通用的方法。
