Green Synthesis Of β-cyclodextrin Metal-organic Frameworks And The Adsorption Of Quercetin And Emodin

As a second-generation macromolecule organic compound in supramolecular chemistry,β-cyclodextrin(CD)has special structure of internal hydrophobicity and external hydrophilicity.It can improve the properties of guest molecules by forming inclusion complexes with many guest molecules through hydrophobic interaction,van der Waals force and hydrogen bond.At present,it has important applications in various fields.But there are also some drawbacks in natural CD.Therefore,chemical modification of cyclodextrin is necessary in order to broaden the application range of β-cyclodextrin.In recent years,the research of single-modified and bridged-modified β-cyclodextrin derivatives has developed rapidly,and the physical and chemical properties of these derivatives have been improved correspondingly,however,little research has been done on cyclodextrin metal-organic framework materials.Based on the high specific surface area,adjustable pore size and easy functionalization of metal-organic framework materials,it has attracted wide attention of researchers and has been widely used in many fields,such as gas adsorption,storage of clean gas fuels,separation and analysis,catalysis,drug carriers and so on.In this paper,two new cyclodextrin metal organic framework materials(CD-MOFs)were prepared,and their drug-loading behaviors for quercetin and emodin were further studied using K-CD-MOFs as carriers.The main contents of this paper are as follows:1.The structure and properties of β-cyclodextrin and its derivatives are introduced.The properties,types,synthesis methods and application fields of metal organic framework materials are summarized.Finally,the main research contents of this subject are put forward.2.Two new type of cyclodextrin metal-organic framework material(K-CD-MOFs 、 Na-CD-MOFs)was synthesized by vapor diffusion method.The structure of the porous material was analyzed by X-ray single crystal diffractometer and characterized by infrared spectrum,X-ray powder diffraction,scanning electron microscopy and thermogravimetric analysis.The experimental results showed that the porous material was successfully synthesized and could be used as the raw material for drug loading in the next step.3.QU/K-CD-MOFs drug-loaded complex was prepared by impregnation method and characterized by infrared spectrum,X-ray powder diffraction and thermogravimetric analysis.Then the loading characteristics of K-CD-MOFs and drugs adsorption behavior was studied by changing the reaction time,temperatures,MOFs quality,initial drugs concentration and pH value.The experimental results showed that the maximum drug loading of the system was 150.2 mg/g when the temperature was 45°C the reaction time was 48 h,the quality of K-CD-MOFs was 30 mg,the initial concentration of quercetin was 3.2 mg/ml and the pH was 6.In addition,the pseudo-second-order model kinetic model is more suitable for drug-loading adsorption by fitting the kinetic model.The interaction between quercetin and K-CD-MOFs mainly depends on van der Waals force and hydrogen bond.The loading adsorption behavior of quercetin shows that some organic drug molecules can be chemisorbed by K-CD-MOFs.4.EMO/K-CD-MOFs drug-loaded complex was prepared by impregnation method,characterized by infrared spectroscopy,X-ray powder diffraction,thermogravimetric analysis,and then K-CD-MOFs was used as drug-loaded adsorbent.The effects of temperature,reaction time,MOFs quality,initial concentration of emodin and pH value on drug-loaded complex were investigated.The results showed that the maximum drug loading was 199.8 mg/g when the temperature was 35 °C,the reaction time was 48 h,the quality of K-CD-MOFs was 30 mg,the initial concentration of emodin was 2.3 mg/ml and the pH was 6.By fitting the kinetic model,we can see that the pseudo-second-order kinetic model is more suitable for the drug-loading adsorption process compared with the pseudo-first-order kinetic rate equation,which is chemical adsorption.The interaction between emodin and K-CD-MOFs mainly depends on Van der Waals force and hydrogen bond.The purpose of this research is to find a natural,degradable,high porosity and high loading drug carrier for emodin loading by K-CD-MOFs,and through the loading of this new material on emodin,the application prospect of emodin in the field of medicine can be broadened.