Detection of glutathione with an "off-on" fluorescent biosensor based on N-acetyl-L-cysteine capped CdTe quantum dots.
This paper reports a quantum dot (QD)-based "off-on" fluorescent biosensor specifically for the determination of glutathione (GSH) with high sensitivity. The biosensor was based on the following two properties. Firstly, the high fluorescence of N-acetyl-L-cysteine (NALC) capped CdTe QDs could be effectively quenched by Hg(2+) due to the binding of Hg(2+) to the NALC on the surface of the QDs and the electron transfer from the photoexcited NALC-capped CdTe QDs to Hg(2+). Secondly, in the presence of GSH, the fluorescence intensity of NALC-capped CdTe QDs was found to be efficiently recovered. Under some optimized conditions, the relatively restored fluorescence intensity was proportional to the concentration of GSH in the range of 4-64 μg mL(-1), with a correlation coefficient of 0.9980 and a limit of detection of 2.49 ng mL(-1). In addition, the established method shows a high selectivity for some amino acids except cysteine. Moreover, to further investigate its performance, the biosensor was applied to the determination of GSH in human serum samples through a standard addition method and determination of normal GSH concentration in original human serum samples with satisfactory results.
School of Chemistry and Chemical Engineering, Southwest University, Chongqing, 400715, China. flyjd6400@163.com.
Xuanping
X
Tan
Jidong
J
Yang
Qin
Q
Li
Qiong
Q
Yang
D000111:Acetylcysteine / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D019187:Cadmium Compounds / Q000737:chemistry*; D004579:Electron Transport; D005978:Glutathione / Q000032:analysis* / Q000097:blood / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D045663:Quantum Dots / Q000737:chemistry*; D012965:Sodium Chloride / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013691:Tellurium / Q000737:chemistry*
D019187:Cadmium Compounds; D012965:Sodium Chloride; D005978:Glutathione; D013691:Tellurium; C028337:cadmium telluride; D000111:Acetylcysteine