title: Label-free colorimetric detection of biothiols utilizing SAM and unmodified Au nanoparticles.
abstract: Herein, a sensitive and selective sensor for biothiols based on colorimetric assay is reported. S-adenosyl-L-methionine (SAM) could induce the selective aggregation of unmodified gold nanoparticles (AuNPs) by electrostatic interaction. In the presence of biothiols, such as glutathione (GSH), homocysteine (Hcy), and cysteine (Cys), AuNPs prefer to react with thiols of biothiols rather than SAM due to the formation of Au-S bond. Thus, the AuNPs turn from the aggregation to the dispersion state, and the corresponding color variation in the process of anti-aggregation of AuNPs can be used for the quantitative screening of biothiols through UV-vis spectroscopy or by the naked eye. Under optimized conditions, a good linear relationship in the range of 0.4-1.2 µM is obtained for Cys, 0.2-0.9 µM for GSH, and 0.6-3.0 µM for Hcys. The detection limits of this assay for GSH, Cys and Hcys are 35.8 nM, 21.7 nM, and 62.4 nM, respectively. This colorimetric assay exhibits rapid operation (within 5 min), high selectivity and sensitivity towards biothiols with tunable dynamic ranges.
authors: Department of Chemistry, Nanchang University, Nanchang 330031, China.
authors: Zhi-Jian
authors: ZJ
authors: Li
authors: Department of Chemistry, Nanchang University, Nanchang 330031, China.
authors: Xiang-Juan
authors: XJ
authors: Zheng
authors: Department of Chemistry, Nanchang University, Nanchang 330031, China.
authors: Li
authors: L
authors: Zhang
authors: Department of Chemistry, Nanchang University, Nanchang 330031, China.
authors: Ru-Ping
authors: RP
authors: Liang
authors: Department of Chemistry, Nanchang University, Nanchang 330031, China.
authors: Zhi-Mei
authors: ZM
authors: Li
authors: Department of Chemistry, Nanchang University, Nanchang 330031, China. Electronic address: jdqiu@ncu.edu.cn.
authors: Jian-Ding
authors: JD
authors: Qiu
mesh_terms: D015374:Biosensing Techniques; D003124:Colorimetry; D003545:Cysteine / Q000302:isolation & purification*; D005978:Glutathione / Q000302:isolation & purification*; D006046:Gold / Q000737:chemistry; D006710:Homocysteine / Q000302:isolation & purification*; D006801:Humans; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry; D008715:Methionine / Q000031:analogs & derivatives / Q000737:chemistry
chemical_list: D006710:Homocysteine; D006046:Gold; D008715:Methionine; D005978:Glutathione; D003545:Cysteine
keywords: Aggregation; Au nanoparticles; Biothiols; Colorimetric; Sam