Design synthesis and applications of fluorescent probes for selective detection of thiols

Abstract

Thiols represent class of organic compounds characterized by having sulfhydryl SH functional group Cysteine Cys homocysteine Hcy and glutathione GSH are three major low molecular weight biothiols which performs various important physiological processes Abnormal levels of these species are linked to various diseases including Alzheimer 8217 s disease cardiovascular diseases cancer skin lesions etc Aromatic thiols produced from volcanic eruption petrol refineries and rubber industries are highly toxic and polluting species These exert adverse effects on human health by targeting the central nervous system kidney and liver Hydrogen sulphide H2S on the other hand is known as the third most important gasotransmitter which has anti inflammatory vasculoprotective and cardioprotective effects Overexposure to H2S leads to unconsciousness olfactory paralysis and brain damage Therefore selective and quantitative detection of these thiol species is the key to early diagnosis of such diseases and thereby in the prevention of the same Present work is dedicated towards the development of fluorescent off on probes for the selective detection of these species Designs of fluorescent probes were done with the aim of discriminating among biothiols arylthiols from biothiols H2S from biothiols etc A GSH sensitive probe was developed based on the chromenoquinoline fluorophore while 4 chloro 7 nitrobenzofurazan probe displayed excellent selectivity for Cys A rationally designed BODIPY based probe displayed selective localization in lysosomes A series of probes were also designed for selective response towards arylthiols Interestingly designed probes with BODIPY iminocoumarin and naphthaleneimide fluorophores displayed very fast response towards the analyte In order to achieve H2S selectivity a cascade reaction based probe was designed successfully Applications of these probes were demonstrated by either live cell imaging or analysis of water samples newline newline