Design,Synthesis And Imaging Of ¹⁹F NMR/Fluorescent Molecular Probes Base On Overexpressing β-Gal In Ovarian Cancer

Objectiveβ-Galactosidase(β-galactosidase,β-gal)is a typical lysosomal hydrolase that catalyzes the hydrolysis of glycosidic bonds and plays an important role in the process of converting lactose to galactose.In normal ovary,β-gal exists in the lysosome of cells,but its enzyme activity is abnormally overexpressed in primary ovarian cancer,and it can be used as a molecular target of primary ovarian cancer.By targeting overexpressed β-gal as a tumor marker in ovarian cancer,we propose a novel mechanism of 19 F NMR/fluorescence imaging dualmodality,in which changes in 19 F NMR chemical shifts reveal the presence of β-galactosidase(or tumor),fluorescence imaging determines the location and size of β-galactosidase(or tumor)and its changes via enhanced fluorescence generated by the dual mechanism of AIE and ESIPT.MethodsFocusing on this new mechanism,we designed 3 molecular probe models with different structures.A total of 76 compounds were synthesized,isolated and identified,of which 52 were new compounds and 27 were target galactosides.Among them,the enzymatic hydrolysis activity was screened out.There are 18 β-gal substrates with great changes in 19 F NMR chemical shift before and after enzymatic hydrolysis,fluorescence properties including response speed,fluorescence intensity change,stability,selectivity and competition.ResultsThrough the cytotoxic activity test,6 probes with a new dual-modality mechanism of 19 F NMR/fluorescence imaging were screened.Further tests in ovarian cancer tumor cells SKOV-3,OVCAR-3 and reference cells He La and MCF-7 showed that F3 and F6 can be used as molecular probes for the new mechanism of 19 F NMR/fluorescence imaging dual-modality for further animal model studies.Conclusions1.F3 can quickly reach a stable state within 5min,with a fluorescence enhancement of 71 times,a good linear relationship(R2=0.99)in the range of 0-12 U/m L β-gal,and good photostability within 180 min.Km=54.35 μM,Vmax=19.21 μM·S-1,with higher affinity and faster catalytic efficiency,while producing strong yellow fluorescence in OVCAR-3 cells(Figure 1).2.The fluorescence intensity of F6 can reach the maximum within 10 minutes,the fluorescence enhancement reaches 105 times,and the large Stokes(188 nm)shift,the lowest detection limit is 0.0093 U/m L,and produces obvious green fluorescence in OVCAR-3 cells(Figure 2).F3,F6 and He La,MCF-7 cells compared significantly,laying a foundation for the new mechanism of 19 F NMR/fluorescence imaging dual-modality in the early detection and treatment monitoring of ovarian cancer.