Anhui Province Key Laboratory of Advanced Catalytic Materials and Reaction Engineering, School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei, Anhui 230009, People's Republic of China.
Anhui Province Key Laboratory of Advanced Catalytic Materials and Reaction Engineering, School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei, Anhui 230009, People's Republic of China.
Talanta. 2018 Aug 15;186:330-336. doi: 10.1016/j.talanta.2018.04.078. Epub 2018 Apr 27.
The discriminative determination of glutathione (GSH) over cysteine (Cys) and homocysteine (Hcy) is still challenging in bioassays due to their similar functional groups. Herein, a novel, simple, rapid, sensitive and cost-effective label-free colorimetric method for the selective determination of GSH over Cys and Hcy was proposed. In this assay, firstly, o-phenylenediamine (OPD) could be oxidized by silver ions (Ag) to produce silver nanoparticles (AgNPs) and pale yellow colored 2,3-diaminophenazine (shorted as OPDox) with absorbance peak center at 429 nm. The as-formed AgNPs could further catalyze the redox reaction between OPD and Ag. In the presence of GSH, GSH could chelate with Ag, inhibiting the oxidation ability of Ag, and link with AgNPs, influence the catalytic ability of AgNPs. Furthermore, GSH possesses strong reducibility to reduce OPDox, resulting in color fading of the detection solution and decrease in absorbance intensity. The proposed Ag-OPD based sensing system exhibited a wide linear range from 2 nM to 1 µM for GSH detection, with the limit of detection as low as 1.7 nM. Moreover, this developed method was successfully applied to GSH detection in plasma and urine samples with satisfied results.
由于其相似的官能团，在生物测定中，对谷胱甘肽（GSH）与半胱氨酸（Cys）和同型半胱氨酸（Hcy）进行区分测定仍然具有挑战性。在此，提出了一种新颖、简单、快速、灵敏且具有成本效益的用于选择性测定 GSH 相对于 Cys 和 Hcy 的无标记比色法。在该测定中，首先，邻苯二胺（OPD）可被银离子（Ag）氧化，生成银纳米颗粒（AgNPs）和浅黄色的 2,3-二氨基吩嗪（简称 OPDox），其吸收峰中心在 429nm。形成的 AgNPs 可进一步催化 OPD 和 Ag 之间的氧化还原反应。在 GSH 存在下，GSH 可与 Ag 螯合，抑制 Ag 的氧化能力，并与 AgNPs 结合，影响 AgNPs 的催化能力。此外，GSH 具有很强的还原性，可还原 OPDox，导致检测溶液褪色和吸光度强度降低。基于 Ag-OPD 的传感系统对 GSH 的检测表现出从 2 nM 到 1 µM 的宽线性范围，检测限低至 1.7 nM。此外，该方法成功应用于血浆和尿液样品中的 GSH 检测，结果令人满意。
