Design And Synthesis Of Fluorescent Probes For Amino Acids And Carbon Monoxide And Their Cell Imaging Studies

There are many active species in living systems,such as ions,small molecules,amino acids,enzymes,peptides,and proteins,etc.,which play a vital role in the metabolism of the body.Fluorescent probe technology has attracted wide attention in the fields of chemistry,biology,environmental science,and medicine because of its advantages such as convenience,easy operation,low cost,and interference from external magnetic fields.Therefore,designing and synthesizing new fluorescent probes with good sensing performance to identify these active species in living organisms and to perform visual quantitative and qualitative analysis on these active species has become a hot topic for researchers all over the world.This article is mainly divided into three parts,as follows:Chapter 1,introduces the research background and recognition mechanism of fluorescent probes,including photo-induced electron transfer?PET?,intramolecular charge transfer?ICT?,and fluorescence resonance energy transfer(Fluorescence resonance energy transfer?FRET?,Excited-state Intramolecular Proton transfer?ESIPT?,Aggregate-induced emission?AIE?.The research progress and status of several types of fluorescent probes are discussed in detail by examples.Chapter 2,We have successfully developed a new type of fluorescent probe,PNT by introducing a naphthalimide fluorophore and N-p-toluenesulfonyl-1,2-diphenylethylenediamine?TsDPEN?.This probe has good recognition performance for Cu²⁺in aqueous solution.After the probe PNT is combined with Cu²⁺,the fluorescence is rapidly quenched.The resulting PNT-Cu complex gradually restores fluorescence after adding histidine and cysteine,and has good selectivity.Cell imaging experiments have shown that the probe PNT can penetrate cell membranes and achieve fluorescence imaging of Cu²⁺,histidine,and cysteine in living cells.This results indicate that the probe PNT has practical application value in biological systems.Chapter 3,Based on the fluoroboropyrrole BODIPY fluorophore,we designed and synthesized two small-molecule fluorescent probes,PNC and PEC.These two probes can selectively recognize carbon monoxide in PBS buffer and aqueous solution.Due to the fluorescence quenching effect of the nitro group,the probe has very weak fluorescence.In the presence of carbon monoxide,the nitro group will be reduced to an amino group to enhance the fluorescence of the system,thereby achieving the purpose of detecting carbon monoxide.The two probes showed excellent recognition performance for carbon monoxide,with good sensitivity and selectivity.In addition,the results of cell imaging experiments show that the probe can not only recognize carbon monoxide in cells,but also endogenous carbon monoxide produced by cells under the stimulation of heme.