Synthesis And Biological Application Of The Fluorescent Probes For Hypochlorous Acid Based On Difluoroboron Dipyrromethenes

Hypochlorous acid（HOCl）,one of the representatives of reactive oxygen species（ROS）,is often used as an original regulator in the organism and is the primary sterilization substance in the biological immune system.HOCl is generated from the reaction of H₂O₂ and Cl^-catalyzed by myeloperoxidase（MPO）in the life activities of organisms.However,Excessive accumulation of HOCl could result in damage to tissues and organs.Therefore,the development of fluorescent probes for HOCl detection holds significant biological and medical importance.The BODIPY fluorescent dyes,with their excellent photophysical and chemical properties,such as high quantum yield and stability,are extensively employed in fluorescence molecular probes and biomarkers,making them a popular research area.A new fluorescent probe BOD was designed and synthesized,containing BODIPY as the fluorescent group and 2-hydrazinobenzothiazole as the recognition group.Due to the existence of C=N isomerization,the probe BOD exhibited no fluorescence.Nonetheless,the probe BOD demonstrated selective recognition of HOCl in a PBS buffer solution and the fluorescence intensity of the probe was significantly enhanced.Equilibrium was achieved within 40 seconds of the reaction.Additionally,the probe BOD exhibited high selectivity and strong anti-interference ability,while presenting a robust linear relationship（LOD=0.22μM）with ClO^-.In cellular systems,the probe BOD demonstrated low cytotoxicity and the capability to detect exogenous hypochlorous acid.A fluorescent probe BOE was designed and synthesized,containing BODIPY as the fluorescent group and 2-hydrazinopyridine as the recognition group.Upon specific reaction with hypochlorous acid,the C=N double bond of the probe was oxidized to a carboxyl group,leading to the release of fluorescence.The color of the probe altered from purple to yellow after the reaction.Equilibrium was reached within 2 seconds,presenting a robust linear relationship with ClO^-（LOD=66 n M）.Furthermore,the probe BOE displayed specific reaction to ClO^-in the presence of various reactive oxygen species,reactive nitrogen species,and metal ions.Low cytotoxicity and fluorescence imaging experiments demonstrated that the probe BOE could detect exogenous hypochlorous acid in cells.A fluorescence probe BODIPY-OXIME was designed and synthesized,containing BODIPY as fluorophore and two oximes as recognition groups.The probe had almost no fluorescence due to the existence of C=N isomerization.The probe reacted eacted specifically with hypochlorous acid,resulting in the formation of aldehyde groups and releasing fluorescence.The color of the probe changed from red to yellow after the reaction,with a rapid response time（4 seconds）.The probe exhibited a robust linear relationship to ClO^-（LOD=0.42μM）.In the presence of various reactive oxygen species,reactive nitrogen species,and metal ions,the probe demonstrated specific response only to ClO^-,highlighting the excellent selectivity and anti-interference ability of BODIPY-OXIME.The probe successfully detected hypochlorous acid concentrations in disinfectants.