Study On The Design,Synthesis And Biological Application Of β-Galactosidase Fluorescent Probe

The β-galactosidase(β-gal)is a kind of glycosidolytic enzyme,which hydrolyses β-galactose to monosaccharide by hydrolyzing glycosidate bonds.It is the key worker in the decomposition of lactose to galactose and glucose.Therefore,it is very important for biology.Because β-gal is overexpressed in primary ovarian cancer,it is a molecular target for visualizing peritoneal metastasis of ovarian cancer.And the enzyme activity of β-gal is increased in primary ovarian cancer compared with normal ovaries.In addition,β-gal is also an important bio-marker of cell aging.Therefore,the β-gal is very important in medical research,genetic diagnosis,biological immunity and so on.And it is very necessary to provide effective methods to identify the source of the enzyme.Fluorescent probes can be a powerful tool for tracking enzyme activity and have attracted the attention of many researchers due to their non-invasive,scalable and real-time response.Therefore,the design and synthesis of fluorescent probes with specificity and high sensitivity are particularly important for the detection of β-gal.In this paper,three fluorescent probes are designed and synthesized for the specific detection of β-gal.And their spectral properties and bioimaging applications are also studied.(I)A two-photon fluorescent probe G-GAL was developed.This probe uses GCTPOC as a fluorescent reporter molecule and uses a small molecule cleavable by β-galactosidase as an initiator of enzyme activity.This probe is designed to detect β-galactosidase in living cells and tissues.The probe G-GAL has the advantages of rapid reaction,greater fluorescence enhancement and strong specificity.In addition,the probe G-GAL also has excellent tissue penetration performance.(II)A fluorescent probe ESIPT-GAL based on the ESIPT mechanism was developed.The β-galactosylase fluorescent probe(ESIPT-GAL)based on ESIPT mechanism was constructed with the chromophore derived from ESIPT fluorescent dye HBT as the signal reporter group and β-galactose as the response group.The probe ESIPT-GAL had large fluorescence signal enhancement,relatively low background fluorescence and high sensitivity to β-galactosidase.Moreover,the probe had the advantages of fast response speed and high selectivity to various interfering substances.Cell imaging experiments showed that the probe ESIPT-GAL could be used to detect β-galactosidase in living cells.(III)A β-galactosidase fluorescent probe(TR-G)was developed,which uses Rho as a fluorophore and connects it to galactose by an ether bond to detect β-galactosidase.The probe TR-G had high selectivity and sensitivity,and had an emission wavelength greater than 600 nm.Biological imaging experiments showed that TR-G could detect β-galactosidase in vivo and in vitro.