The Design,Synthesis And Properties Study Of Fluorescent Probe For Reactive Sulfur Species Based On A Naphthalimide-indole Fused Chromophore

Fluorescent probes have been extensively used in life science research fields such as fluorescence sensing and medical diagnostics because of their high sensitivity and excellent selectivity.Therefore,the development of innovative fluorescent probes with superior performance has far-reaching significance.The dye TPFC4 obtained by the hybridization of naphthalimide and indoles has a long emission wavelength(red emission)and a large Stokes shift(> 100 nm),which is a good framework for constructing fluorescent probes.In this paper,on the basis of dye TPFC4,fluorescent probe TPFC-DNB was designed and synthesized for selective detection of thiophenol,and TPFC-DNBS was developed for discrimination of thiol-containing amino acids over other amino acids.And TPFC-SePh was developed for distinguishing GSH from Cys/Hcy and other amino acids.The contents are as follows:(1)Probe TPFC-DNB was constructed by attaching a sensing group,2,4-dinitrophenyl group,to the core of TPFC4 through a ether bond.Due to the PET process,TPFC-DNB was non-fluorescent.When TPFC-DNB was treated with thiophenol,a nucleophilic substitution reaction occurred,which resulted in the leaving of the sensing unit and the inhibition of PET process,and therefore the fluorescent signal of TPFC4 was restored.This probe exhibited excellent selectivity,a large Stokes shift(140 nm),a red emission(590 nm)and a low detection limit(36nM)and a rapid respond time.Furthermore,this probe was successfully used in the detection of thiophenol in living cells.(2)Probe TPFC-DNBS was constructed by replacing 2,4-dinitrophenyl group(DNB)with 2,4-dinitrobenzenesulfonyl group(DNBS)as a sensing unit group for thio-containing amino acids.TPFC-DNBS was non-fluorescence due to the PET process from DNBS group.The addition of the mercapto amino acids(Cys,Hcy and GSH)led to leaving of sensing unit group and realease the free TPFC4,resulting a strong fluorescence signal.This probe has an 590 nm emission wavelength and a 137 nm Stokes shift in detecting mercapto amino acids.This probe was successfully used in the detection of endogenous and exogenous mercapto amino acids in living cells.(3)Using phenylselenyl moiety(–SePh)as a sensing unit,probe TPFC-SePh was constructed on the bases of combination of dyes TPFC4 and coumarin.This probe was able to discriminate GSH from Cys/Hcy and other amino acids.The interaction of GSH with this probe can triggered the leaving of –SePh,resulting in a strong fluorescence signal.However,Cys/Hcy reacted with TPFC-SePh accompanying the leaving of –SePh,and subsequently a rearrangement reaction occurred,which resulted in a weak fluorescence signal.Probe TPFC-SePh displayed emission wavelength centered at 570 nm and a 120 nm Stokes shift in the detection of GSH.It also has good selectivity and anti-interference ability.