The Recognition Characteristic Of Functional Molecules Based On Bile Acids And Hydrogels Based On Triterpenoids

As important biogenic homologues of natural products,bile acids and triterpenoids have been playing critical roles in the field of drug research due to their good bioactivity and biocompatibility.Lately,more attention has been paid to their applications in supramolecular recognition and hydrogel on account of their chiral rigid scaffolds and multiple modification sites,which render them as ideal building blocks in designing versatile functional molecuels.These studies not only explore the importance of bile acids and triterpenoids in life process,such as material transportation and molecular recognition,but also open new scenarios in natural product-based biomaterials.In this dissertation,a series of deoxycholic acid-based fluorescent probes have been developed by modifying different binding motifs and functional groups on skeletons,and these probes exhibit high selectivity and sensitivity towards various ions and small chiral molecules.Meanwhile,by the introduction of hydrophilic groups,glycyrrhetinic acid-based hydrogels were formed,and those gels can either be used in selective dye adsorption and sustainable release,or cell culture.The major results are as follows:1.A deoxycholic acid-coumarin conjugate was synthesized by click reaction,and this probe exhibited high selectivity towards Cu2+ion.The resulting copper complex showed turn-on recognition ability in fluorescence for H2PO4-ion selectively and amino acids quantitatively.By using Cu2+ ion and H2PO4-ion as inputs and the emission as the output signal,respectively,an IMPLICATION(IMP)logic gate has been generated.2.A tweezer molecule based on deoxycholic acid and salen-type motif was developed,which could recognize Zn2+ ion selectively either in solution or test-strips through a turn-on fluorescence effect.Moreover,this chemosensor can be used in living cells imaging because of its good biocompatibility.Furthermore,the resulting zinc complex exhibited turn-off response towards H2PO4-ion,thus leading to the fabrication of an INHIBIT(INH)logic gate using Zn2+ion and H2PO4-ion as inputs and the emission as output,respectively.3.A deoxycholic acid-binaphthol macrocycle was synthesized,and such macrocyle showed selective recognition of Hg2+ion.The resulting mercury complex could furtherdiscriminate amino acids enantioselectively on account of the chiral scaffold of deoxycholic acid,as well as its macrocylic structure.4.Triterpenoid-based hydrogels were found for the first time by the introduction of hydrophilic groups.Among them,sodium glycyrrhetinate could form a hydrogel primarily promoted by dipole-dipole interactions,and this hydrogel can be utilized in dye adsorption and sustainable release.While a phosphate ester of glycyrrhetinic acid formed a gel in mixed solvent of DMSO-water through the intermolecular hydrogen bonding.After the removal of DMSO by cell culture medium,this biocompatible hydrogel was suitable for cell culture.