Study Of New Methods For The Electrochemical Detection Of Glutathione

Glutathione?GSH?as the most abundant biothiol in the living organisms,it plays a critical role in many cellular functions.In recent years,more and more reports about GSH have revealed the abnormal level of cellular GSH has been found to be closely related with many dangerous human diseases.It is still urgently needed to develop some simple but efficient methods for monitoring GSH under both physiological and pathological conditions.However,electrochemical sensor has the features of low cost,simple operation,high sensitivity and so on,so it may has an important application prospect to design electrochemical methods for detecting glutathione.In our studies,we have been respectively established two new methods for electrochemical detection of glutathione based on mercury ion mediated strand displacement reaction and glutathione mediated ligand exchange reaction.The main content has been described as follows:1.Electrochemical detection of glutathione based on Hg²⁺-mediated strand displacement reaction strategyGlutathione plays an important role in numerous cellular functions,and the abnormal GSH expression is closely related with many dangerous human diseases.In this work,we have proposed an electrochemical method for quantitative detection of GSH based on an Hg²⁺-mediated strand displacement reaction.Owing to the specific binding of Hg²⁺with T-T mismatches,helper DNA can bind to 3?terminal of probe DNA 1 and initiate the displacement of probe DNA 2 immobilized on an electrode surface.When there is glutathione,Hg²⁺-mediated strand displacement reaction can be inhibited by the chelation of GSH with Hg²⁺,thereby leading to an obvious electrochemical response obtained from methylene blue that is modified onto the electrode.Our new method can sensitively detect GSH in a wide linear range from0.5 nM to 5?M with a low detection limit of 0.14 nM,which can also easily distinguish target molecules in complex serum samples and even cell extractions.Therefore,this new method may have great potential to monitor GSH in the physiological and pathological condition in the future.2.Electrochemical detection of intracellular glutathione based on ligandexchangeassistedreleaseofDNA-templatedsilver nanoparticlesIn this work,we have proposed an effective electrochemical method for the detection of intracellular GSH based on the high-affinity binding of GSH and silver nanoparticles?AgNPs?.AgNPs can be formed through the reduction of silver ions on the surface of a DNA template,and can be released from the template DNA through the ultra-stable Ag-S interaction in the presence of GSH.After removing the unreleased AgNPs from the reaction solution with the aid of the magnetic graphene,GSH-coated AgNPs can be dissolved to release a large amount of silver ions and thus lead to an obvious electrochemical response.The electrochemical results have shown that our new method can sensitively and specially detect GSH in a linear range from0.1 nM to 1?M with a low detection limit of 0.023 nM,which can be successfully applied to detect the intracellular GSH extracted from Hela cells.Therefore,our method may has a great potential in the clinical diagnosis of the related diseases in the future.