Construction And Application Of Biochemical Sensor Based On CHMC Fluorophore

Bioactive small molecules play an important role in organisms.The abnormal level of these molecules in organisms is often associated with various diseases.Therefore,the accurate detection of these active molecules in organism can provide an important reference for disease diagnosis and treatment.CHMC fluorophore is a kind of cyanine derivative,which possess various advantages,such as long emission wavelength and easy to modify.Based on these characteristics of CHMC fluorophore,two different types of near-infrared fluorescent probes were constructed to detect leucine aminotranspeptidase（LAP）and hydrazine（N₂H₄）in vivo.（1）A ratiometric and near-infrared fluorescence probe was constructed to detect leucine aminopeptidase.Based on the optical properties of the near-infrared fluorescent dye CHMC,a series of near-infrared fluorescent probes were constructed by conjugating dipeptides（Cys Leu）onto CHMC.In order to achieve a ratiometric detection of LAP,we introduced different substituent groups on CHMC,by adjusting the electronic effect,we finally developed a ratiometric fluorescence probe for LAP recognition.In the presence of LAP,the amide bond in Cys-Leu will be cleavaged and a free amino group will be released,which triggered the intramolecular S→N rearrangement,and a significant fluorescence change will be occurred,realizing the ratio detection of the LAP.In the in vitro test experiment,the fluorescent probe HCHMC-S-Leu showed a good detection effect,its emission wavelength was blue shifted from 683nm to 620nm,and the detection limit was 40.5 ng·mL^-1,and the response time was also relatively short.In the in vivo experiment,we successfully realized the efficient tracking and detection of LAP in cancer cells and zebrafish.（2）Construction of near-infrared fluorescence probe for recognition of hydrazine（N₂H₄）.In order to make the emission wavelength shift to the near-infrared region,we introduced amino substituents to CHMC and constructed a new fluorescence group（CH-N）.Based on the optical properties of CH-N,three fluorescent probes CH-NO1,CH-NO2 and CH-NO3 were constructed by introducing bromoalkyl ester,bromoalkyl carbonate and thiophene ester to CH-N.All probes can interact with hydrazine,and cause a significant fluorescence change.After systematic analysis and comparison of the three probes,it was found that CH-NO1 had the most significant change in the fluorescence signal at 640nm,the signal-to-noise ratio was relatively high,and it had a low detection limit(LOD=2.7x10^-8M),which was more conducive to the efficient detection of molecular hydrazine.