Application Of Copper-containing Metal Organic Gel In Fluorescence Detection Of Biomolecules

Metal-organic gels?MOGs?is a new kind of metal organic hybrid material,formed by self-assembly of metal ions and organic ligands in organic solvents or water through coordination bond and a series of noncovalent forces such as hydrogen bonds,hydrophobic interactions,dipolar interactions,electrostatic interactions and?-?stacking.According to the different metal centers,coordination geometries and ligands,MOGs exhibits different properties such as magical optical property,tunable catalytic and mechanical property.Therefore,MOGs as a new type of intelligent soft material,has potential application in the fields of catalysis,chemical sensing,adsorption and drug loading.This is devoted to the application of Cu???-based metal organic gel as fluorescence anisotropy amplifier and artificial enzyme in fluorescence analysis of prostate specific antigen?PSA?and glucose and cysteine.The details are as the follows?1?Cu???-based metal-organic gel enhance fluorescence anisotropy for detection of PSAThe detection of PSA was realized by using the method of amplifying the anisotropy of fluorescence?FA?due to the large volume and mass of Cu-MOG which prepared by2,6-bis?2-benzimidazyl?pyridine?BBPY?and Cu²⁺.The dye-labeled PSA aptamer?PA?product can be adsorbed onto the benzimidazole derivative-containing Cu-MOG via electrostatic incorporation and strong?-?stacking interactions,which significantly increased the FA value due to the enlargement of the volume of the PA/Cu-MOG complex.With the introduction of target PSA,the FA value was obviously decreased on account of the specific recognition between PSA and PA which resulted in the detachment of PA from the surface of MOGs.Hence,a method for PSA detection with enhanced fluorescence anisotropy was developed.Under the optimal conditions,the linear range of PSA is 0.5-8 ng/mLwith a detection limit of 0.33 ng/mL.We further applied this method to the detection of PSA in human serum and with satisfactory results.?2?Copper???/cobalt???bimetallic organic gel with enhanced peroxidase-like activity for determination of glucoseA series of Cu???/Co???bimetallic organic gel?Cux/Coy-MOG?was prepared by mixing the bridging ligand 2,4,6-tri?4-carboxyphenyl?-1,3,5-triazine?H₃TATAB?with Cu²⁺and Co²⁺ions at room temperature.The as-prepared Cux/Coy-MOG can catalyze the reaction of H₂O₂ with terephthalic acid?TPA?,producing a blue fluorescence product with the maximum excitation/emission at 315/446 nm.The Cu_0.5/Co_0.5-MOG shows the highest peroxidase-like activity among the other prepared Cux/Coy-MOG,and internal redox cycle mechanism of peroxidase-like activity enhancement was proposed through X ray photoelectron spectroscopy?XPS?and cyclic voltammetry measurements.In addition,based on the peroxidase-like activity of Cu_0.5/Co_0.5-MOG,a fluorescence analysis strategy for the determination of glucose was established.the linear range of glucose is0.5-120?M with a detection limit of 0.33?M.The method was successfully applied to the detection of glucose in serum and good results were obtained.?3?Cu-MOG derivatives with enhanced multiple enzyme-like activities for the detection of cysteine by cascade reactionCu-MOG was prepared from Cu²⁺and H₃TATAB under mild conditions.Based on the thixotropy of MOGs,a stable 3D Cu-based metal-organic porous network?Cu-MOPN?with intrinsic oxidase-and peroxidase-mimicking activities has been successfully fabricated from 1D Cu-based metal-organic gel?Cu-MOG?under microwave irradiation.Owing to the high BET surface area,hierarchically porous structure and inherent mass transfer channels,the Cu-MOPN shows higher catalytic activity than that of Cu-MOG.Furthermore,based on the excellent cysteine oxidase and hydrogen peroxide mimic enzyme activities of Cu-MOPN,a fluorescence analysis platform for the highly selective detection of cysteine was established by the cascade reaction.Under the optimal conditions,the linear range of cysteine is 1-50?M,and the detection limit is 93 nM.The method was applied to the determination of cysteine in serum,and satisfactory results were obtained.