A reversible competition colorimetric assay for the detection of biothiols based on ruthenium-containing complex.
A novel reversible colorimetric sensor, which based on a competitive ligation of Hg(2+) by thiols, cysteine (Cys) or glutathione (GSH), and thiocyanate (SCN) on the N3 dye (bis(4,4'-dicarboxy-2,2'-bipyridine) dithiocyanato ruthenium (II)), was developed for the detection of biothiols. First, Hg(2+) ions coordinate to the sulfur atom of the dyes' SCN groups, and this interaction induces a change in color from red to yellow, owing to the formation of a complex of Hg(2+)-N3. Then, in the presence of biothiols, the red color of N3 is recovered concomitantly with the dissociation of the Hg(2+)-N3 complex, due to the extraction of Hg(2+) by biothiols. Thus the corresponding color variation in the process of the dissociation of the Hg(2+)-N3 complex can be employed for the quantitative detection of thiols using UV-vis spectroscopy. In particular, the transformation can be readily viewed with the naked eye. A good linear relationship between the change in absorbance (ΔAbs) of Hg(2+)-N3 at 461 nm and the thiol concentration was obtained in the range of 0.5-25 μM, and the detection limits are then calculated to be 57 and 52 nM for Cys and GSH, respectively. The proposed colorimetric assay displays a high selectivity for Cys over various other amino acids and GSSG (oxidized glutathione).
College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083, PR China.
Yuanqiang
Y
Hao
Dandan
D
Xiong
Liqiang
L
Wang
Wansong
W
Chen
Binbin
B
Zhou
You-Nian
YN
Liu
D015082:2,2'-Dipyridyl / Q000031:analogs & derivatives / Q000737:chemistry*; D001667:Binding, Competitive; D002413:Cations, Divalent; D003116:Color; D003124:Colorimetry / Q000379:methods; D003545:Cysteine / Q000032:analysis*; D005978:Glutathione / Q000032:analysis*; D008628:Mercury / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D012428:Ruthenium / Q000737:chemistry*; D013053:Spectrophotometry; D013861:Thiocyanates / Q000737:chemistry
D002413:Cations, Divalent; D009942:Organometallic Compounds; D013861:Thiocyanates; D015082:2,2'-Dipyridyl; D012428:Ruthenium; D008628:Mercury; D005978:Glutathione; D003545:Cysteine; C031760:thiocyanate
Competitive ligation; Reversible colorimetric assay; Ruthenium-containing dye; Thiol detection