Au/Metal–Organic Framework Nanocapsules for Electrochemical Determination of Glutathione

Abstract

An ultrasensitive signal amplification strategy has been developed using Au@Cu-MOF nanocapsules as an electrochemical platform for the determination of glutathione (GSH) based on the signal output from solid-state electrochemistry of cuprous chloride (CuCl). The Au@Cu-MOF nanocapsule, with a metal−organic framework (MOF) sandwich shell and an encapsulated Au nanoparticle layer, was prepared via coordinate replication of a Cu 2 O redox-template strategy. Also, the Au@Cu-MOF nanocapsule-modified electrode achieved boosting signal output in the presence of chlorine ions (Cl − ) by solid-state electrochemistry of CuCl, which showed a pair of remarkable peaks. However, in the presence of GSH, the phenomenon termed as "crowding-out effect" appeared, in which the specific Cu−GSH interaction triggered the competitive reaction with the conversion of CuCl into nonelectroactive substance of Cu−GSH, leading to a sharp decrease in the peak current of CuCl. The Au@Cu-MOF nanocapsule-modified electrode showed high sensitivity toward GSH owing to the specific electrochemical output at a relatively low potential, which can effectively shield the possible interferences from complex physiological surroundings. The crowding-out effect can also improve the selectivity, particularly for complex analytical samples in terms of electrode fouling. The electrochemical sensor showed a wide linear range of 0.01−40 nM and 40 nM to 10 μM, with a detection limit of 2.5 pM (S/N = 3). The sensor can be utilized for the determination of GSH in various real vegetable and serum samples with satisfactory results. Besides, it can also be applied for probing GSH in the lysates of Romas cells with good sensitivity, which brings dawn for early diagnosis of cancer in clinics. Moreover, the ultrasensitive and selective solid-state CuCl electrochemistry-promoted signal amplification strategy as well as the excellent stability and special nature of Au@Cu-MOF nanocapsules may promise their wide application in biological and food analysis fields.

Turn-on signal fluorescence sensor based on DNA derived bio-dots/polydopamine nanoparticles for the detection of glutathione

“…The methods currently used for the detection of GSH are colorimetry, 5–7 electrochemical analysis, 8–10 high performance liquid chromatography 11,12 and fluorescence analysis. 13–15 Among these analytical methods, the fluorescence analysis method overcomes the defects of other methods such as complex operation, high equipment requirements, poor sensitivity and selectivity, and being time-consuming, which makes it more promising for detecting GSH.…”

Towards Development of Molecularly Imprinted Electrochemical Sensors for Food and Drug Safety: Progress and Trends

“…The last, but not least, electrochemical signal label is closely related to detection sensitivity and accuracy, and the design of the signal includes an electroactive substance and signal amplification strategy. To indicate analytes, various electroactive substances are used as electrochemical signals with signal amplification to improve detection sensitivity [ 22 , 23 ]. However, the single-signal output is prone to be influenced by external environmental interferences, so it is necessary to design the signals to eliminate the interferences and enhance the sensitivity.…”

Ultrasensitive and Selective Detection of Glutathione by Ammonium Carbamate–Gold Platinum Nanoparticles-Based Electrochemical Sensor

“…However, it is difficult to detect the concentration of glutathione due to the instability of glutathione in solution and its tendency to be oxidized to form disulfides. Thus far, scientists have proposed several different analytical methods for glutathione analysis, such as ultraviolet spectrophotometry [ 6 ], fluorescence spectrophotometry [ 7 ], mass spectrometry [ 8 ], high-performance liquid chromatography [ 9 ], flow injection analysis [ 10 ], and enzymatic [ 11 ] and electrochemical methods [ 12 , 13 , 14 , 15 , 16 ]. However, most of the aforesaid methods have some limitations, such as the necessity for complex and expensive instruments, the demand for skill-based operation, and time-consuming nature.…”