Construction And Evaluation Of Dual-site Fluorescent Probes For Microenvironment

As two important members of reactive oxygen species family,hypochlorite(Cl O^-)and hydrogen peroxide(H₂O₂)commonly coexist in organism and are involved in the same physiological and pathological processes.In addition,as an important microenvironment,polarity affects the progress of many biochemical reactions,so it must be closely related to the various functions of reactive oxygen species.In order to further reveal their intricate internal relationships in physiology and pathology,it is critical to develop fluorescent probes that simultaneously detect them.Herein,based on the potential relationships between Cl O^-and H₂O₂ or polarity,two dual-site fluorescent probes for multi-response detection of Cl O^-/H₂O₂ and Cl O^-/polarity were designed and synthesized,respectively.In this paper,the first dual-site fluorescent probe Geisha-1 for the simultaneous detection of Cl O^-and H₂O₂ was constructed by chemically grafting N,N-dimethylthiocarbamate and borate to a coumarin-1,8-naphthalimide fluorescence resonance energy transfer(FRET)platform.The UV-Vis absorption and fluorescence spectra were recorded and analyzed.As a result,the probe presented two different turn-on fluorescence response modes toward Cl O^-and H₂O₂ respectively,and a response mode based on FRET mechanism to Cl O^-+H₂O₂(the coexistence of Cl O^-and H₂O₂).In addition,Geisha-1 exhibited excellent sensitivity and high selectivity as well as quantitatively detecting Cl O^-and H₂O₂.Furthermore,the cell and tissue imaging results illustrated that probe Geisha-1 not only displays low cytotoxicity,cell membrane and tissue permeability,but also can image the spatial distribution of Cl O^-and H₂O₂ through three channels.In this paper,the dual-site fluorescent probe Joka-1 for detection of Cl O^-and polarity was designed by introducing chemical and physical response mechanisms and synthesized by modifying a coumarin-triphenylamine fluorophore with N,N-dimethylthiocarbamate,and its performance was preliminary characterized by spectral methods.The results showed that Joka-1 exhibited a fast,sensitive,highly selective and quantitatively detectable turn-on response mode toward Cl O^-,while spectral redshift and enhanced fluorescence intensity toward the increasing of polarity,which presumably caused by the intramolecular charge transfer(ICT)and aggregation-induced emission(AIE)effect respectively.In addition,the maximum emission wavelength can be used as the response for polarity,which not only has the potential for quantitative detection,but also can avoid the interference of viscosity and p H,while the fluorescence intensity can be used as an auxiliary response signal for qualitative detection of polarity,which is attributed to interference of viscosity.