Department of Chemistry, Sharif University of Technology, Tehran 111559516, Iran.
ACS Appl Mater Interfaces. 2024 Oct 2;16(39):52080-52091. doi: 10.1021/acsami.4c12126. Epub 2024 Sep 19.
Biothiols, characterized by thiol groups, exhibit remarkable affinity for certain metals, playing pivotal roles in intracellular and extracellular biological processes. Fluctuations in their levels profoundly impact overall physiological health. Despite the development of various probes for biothiol detection and quantification, their inability to monitor thiol-to-disulfide state transitions persists as a limitation. Given their association with pathologies, early detection remains imperative. Gold nanorod (AuNR)-based colorimetric probes have garnered attention for their utility in visual diagnostic assays. Herein, we present a cost-effective, and sensitive multicolor ratio measuring probe enabling on-site simultaneous identification, discrimination, and quantification of essential biothiols─cysteine (CYS), glutathione (GSH), cystine (CYSS), and glutathione disulfide (GSSG)─while also quantifying thiol-to-disulfide ratios. Our investigation clarifies the probe's functionality, elucidating etching and antietching mechanisms based on sulfhydryl group coordination with Hg. This coordination impedes gold amalgam formation, facilitating discriminative detection via AuNR size and aspect ratio modulation, validated by transmission electron microscopy. Notably, distinct rainbow-like fingerprint patterns were discernible both visually and spectroscopically for the aforementioned biothiols and their respective thiol-to-disulfide ratios. Subsequent qualitative and quantitative analyses via linear discriminant analysis (LDA) and partial least squares regression revealed linear correlations over broad concentration ranges (CYS: 1.9-40 μmol L, GSH: 3.2-200.0 μmol L, CYSS: 2.0-70.0 μmol L, GSSG: 3.7-100.0 μmol L), with detection limits of 0.66 μmol L (CYS), 1.07 μmol L (GSH), 0.69 μmol L (CYSS), and 1.24 μmol L (GSSG). Moreover, thiol-to-disulfide ratios exhibited linear patterns within 0.2-5 μmol L, with detection limits of 0.13 and 0.09 μmol L, and exceptional analytical sensitivities of 32.648 and 49.782 for (CYS/CYSS) and (GSH/GSSG), respectively. Lastly, we evaluated the probe's performance in complex matrices relative to aqueous media, both quantitatively and qualitatively.
生物硫醇的特点是含有巯基，对某些金属表现出显著的亲和力，在细胞内和细胞外的生物过程中起着关键作用。它们的水平波动对整体生理健康有深远的影响。尽管已经开发出各种用于生物硫醇检测和定量的探针，但它们无法监测巯基-二硫键状态转变仍然是一个限制。鉴于它们与病理学的关联，早期检测仍然至关重要。基于金纳米棒（AuNR）的比色探针因其在可视化诊断测定中的应用而受到关注。在这里，我们提出了一种具有成本效益和高灵敏度的多色比率测量探针，能够现场同时识别、区分和定量必需的生物硫醇——半胱氨酸（CYS）、谷胱甘肽（GSH）、胱氨酸（CYSS）和谷胱甘肽二硫化物（GSSG）——同时定量巯基-二硫键的比值。我们的研究阐明了探针的功能，根据巯基基团与 Hg 的配位阐明了蚀刻和抗蚀刻机制。这种配位阻碍了金汞齐的形成，通过 AuNR 尺寸和纵横比的调制实现了有区别的检测，这通过透射电子显微镜得到了验证。值得注意的是，对于上述生物硫醇及其各自的巯基-二硫键比值，可以通过肉眼和光谱两种方式观察到明显的彩虹状指纹图谱模式。通过线性判别分析（LDA）和偏最小二乘回归进行的后续定性和定量分析显示，在广泛的浓度范围内存在线性相关性（CYS：1.9-40 μmol L，GSH：3.2-200.0 μmol L，CYSS：2.0-70.0 μmol L，GSSG：3.7-100.0 μmol L），检测限为 0.66 μmol L（CYS）、1.07 μmol L（GSH）、0.69 μmol L（CYSS）和 1.24 μmol L（GSSG）。此外，巯基-二硫键比值在 0.2-5 μmol L 范围内呈现线性模式，检测限分别为 0.13 和 0.09 μmol L，并且对于（CYS/CYSS）和（GSH/GSSG），分别具有 32.648 和 49.782 的出色分析灵敏度。最后，我们相对于水相评估了探针在复杂基质中的定量和定性性能。
