Design,Synthesis And Application Of Single-dye-based Ratiometric Fluorescent Probe

Fluorescence analysis is more and more popular because of its high sensitivity and strong selectivity.As an analytical method,fluorescence probe has been used in many aspects,such as environmental monitoring,material labeling,and biological imaging.The commonly used fluorescent probes include organic fluorescent probes,inorganic fluorescent probes and fluorescent quantum dots.The organic molecular fluorescent probe has made rapid development in fluorescence labeling and fluorescence detection due to its advantages of simple synthesis,convenient use and strong pertinence.But there will always be in the environment of the probe to use certain background fluorescence signal interference,and after continuous exploration ratio type fluorescent probes has overcome the effect of these problems,but the ratio of general type fluorescent probes are through two dyes to achieve the purpose of ratio test,although the ratio of this type of probe can be customer service background fluorescence interference,but hard to avoid can appear mutual crosstalk between two dye.Therefore,it is of great significance to develop a ratio fluorescent probe composed of a single dye.This paper is based on this idea to improve the application of organic fluorescent probe in analytical detection and biological imaging.?1?The design of novel ratiometric nanoprobes with two well-resolved flu orescence bands for accurate imaging of lysosomal hypochlorous acid?HCl O?i s significant to understand its biological and pathological behaviors.Herein,we develop a single-dye-doped self-referenced ratiometric nanoprobe?SSRN?for im aging of HCl O in lysosomes under a single-wavelength excitation(?_ex=405 nm).The referenced unit?benzothiazole moiety?and HCl O-responsive unit?rhodami ne B?are integrated into the single dye?HB-Py?to achieve the self-referenced ratiometric effect.The well-dispersed SSRN are prepared by a simple coprecipi tation of the morpholine moiety modified amphiphilic polymers?CO-720-MA?a nd HB-Py.Of note,the two well-resolved fluorescence bands??130 nm?of S SRN could provide accurate imaging of analyte in live cells.Additionally,othe r distinct merits with SSRN are also simultaneously realized,including high wa ter solubility,high sensitivity?detection limit:52 n M?,excellent selectivity,goo d biocompatibility and excellent photostability.Significantly,benefiting from the morpholine moiety,this nanoprobe SSRN can specially locate lysosomes and enable ratiometric imaging of exogenous/endogenous HCl O in lysosomes.?2?The rational development of a versatile tool capable of rapid and cyclic detection of nerve agents is of great significance due to the extreme toxicity of nerve agents.Herein,we report a reversible colorimetric and ratiometric fluorescent probe?DMC-Py?for rapid and cyclic detection of nerve agent mimic?diethyl chlorophosphate,DCP?based on intramolecular charge transfer?ICT?mechanism.When exposed to DCP,the pyridine unit of DMC-Py is quickly converted to pyridinium salt?<7s?,the toxic DCP is simultaneously transformed into non-toxic neutral phosphate,accompanying a rapid color change from light green to dark yellow and fluorescence change from cyan to orange red because of the enhancement of ICT effect.The addition of triethylamine to the corresponding DMC-Py H product can revert to the original state of DMC-Py.Alternating exposure of DMC-Py to DCP and triethylamine can induce the color and dual-emission changes in the both solution phase and filter paper,thereby achieving the reversibility of the probe.The whole probe has the characteristics of good selectivity,fast response time and reversible cycle detection,etc.This strategy can provide important ideas for the rational design of reversible fluorescent probe for nerve agent cycling detection.