Preparation Of New Targeted Anti-cancer Drug Delivery Systems Based On Nano MOFs Composites

Background:Adenocarcinoma is the most common cause of cancer death worldwide.The annual incidence rate of liver disease is among the top five deadliest cancers,and is even higher in developing countries.Rubicund（DOX）is commonly used clinically for the treatment of entity tumorous.However,its poor bioavailability,systemic toxicity and multidrug resistance hinder its clinical application.Therefore,it is necessary to develop a low toxicity,high efficacy method to improve the bioavailability of DOX and improve the therapeutic effect of adenocarcinoma.Metal-organic frameworks（MOFs）show great potential in the biomedical field because of their ordered pore structure,high specific surface area,adjustable composition structure,controllable size and morphology,functional diversity and natural biodegradability.Nano-level MOFs（NMOFs）materials are expected to be a new type of drug carrier.It is because it has many excellent properties such as large specific surface area and large pore size,high molecular loading capacity,post-synthesis modification for various functionlization,open metal sites for stronger interaction with drug molecules,environmentally sensitive and controllable release.Hyaluronic acid（HA）is a natural polysaccharide with unique characteristics in biocompatibility.CD44 is a type of transmembrane glycoprotein with HA as its natural ligand,which can endow NMOFs with the ability to target tumor tissues.Objective:Developed a new type of environmental responses responsive multifunctional drug carrier based on NMOFs.By modifying the targeted molecule HA after synthesis,the targeted delivery of doxorubicin（DOX）can be achieved and the systemic toxicity of DOX can be reduced,therefore the therapeutic effect can be improved.Utilizing the special composition of the new NMOFs material and its sensitivity to environmental p H,the controlled release of anticancer drugs in response to the environment can be achieved.Methods:1.Preparation of MIL-101（Fe）-NH₂nano metal organic framework material by solvothermal method.DOX was load into the material by physical adsorption to form a nano-drug carrier system DOX@MIL-101（Fe）-NH₂（DMN）.Then,HA was used to modify the surface of the nano-drug carrier system to synthesize a new type of nano-drug carrier system DOX@MIL-101（Fe）-NH₂/HA（DMNH）.Using scanning electron microscope（SEM）,specific surface area and porosity analyzer,x-ray diffraction（XRD）,fourier transform infrared（FT-IR）,potential potential（Zeta potential）to characterize its morphology,specific surface area and porosity,crystal structure,functional group structure,particle size and potential information.The best drug loading conditions were obtained by examining the drug loading weight ratio and drug loading time;The drug release behavior were studied under different p H values to get the drug release curve.The uptake of free DOX,DMN and DMNH by Hep G2 cells was detected by laser confocal microscope at different times.The MTT method was used to evaluate the cytotoxicity of free DOX,MIL-101（Fe）-NH₂,DMN and DMNH.2.DOX was choosed as the drug-loading model,and the UIO-66-NH₂nano metal organic framework material synthesized by solvothermal as the carrier.The drug loading process was optimized to obtain the highest drug loading rate.HA was used as a targeting ligand to coat its surface to synthesize a novel nano-drug carrier system DOX@UIO-66-NH₂/HA（DUNH）.The crystal structure,morphology and size,functional group structure,specific surface area and porosity,particle size and potential were characterized using x-ray diffraction（XRD）,scanning electron microscope（SEM）,fourier transform infrared（FT-IR）,ratio Surface area and porosity analyzer,zeta potential（Zeta potential）.The drug loading process was studied under different p H values to get the drug release curve.Confocal laser microscope was used to evaluate the uptake ability of Hep G2 cells to free DOX,DUN and DUNH at different times.The inhibition rate of free DOX,UIO-66-NH₂,DUN and DUNH on Hep G2 cells was compared by MTT method.Results:1.The prepared MIL-101（Fe）-NH₂nanomaterial presents a regular octahedral morphology with a particle size of about 200nm.The electric potential of the nano-drug-loading material increased after loading,indicating that DOX was successfully loaded into MIL-101（Fe）-NH₂.The optimal drug loading rate of MIL-101（Fe）-NH₂was 65.32%.Infrared spectroscopy proved that HA has been successfully combined to the surface of DMN.The release of DOX from DMN and DMNH shows time and p H dependence according to the drug release curve.The drug release rates were 85.90%and 65.04%for DMN and DMNH,on 48 h at p H=5.5.The results of cell uptake experiments show that the prepared nano-drug-loaded particles DMN and DMNH can enter cells through endocytosis.As time increases in the acidic environment of Hep G2 cells,the release of loaded DOX increases and enters the cells.DMNH can transport more anticancer drugs DOX into cells than free DOX and DMN.The results of cytotoxicity showed that DMNH has a higher cell inhibition rate than free DOX and DMN at the same drug concentration.2.UIO-66-NH₂,DUN and DUNH have been successfully prepared.And drug loading and HA coating will not change the crystal structure of UIO-66-NH₂.The scanning electron micrograph shows that UIO-66-NH₂has a regular octahedral morphology with a particle size of about 100 nm.The release of DOX from DUN and DUNH was triggered by p H.When the p H was 5.5 and the time reached 48 h,the drug release rates were 67.55%and 59.16%,respectively.According to the results of the cellular uptake experiment,the fluorescence intensity of Dun and Dunh increased with time,which proves that they can be effectively taken up by tumor cells.As the concentration and time increase,the cell survival rate decreases.The results of cytotoxicity proved that DUNH showed high cytotoxicity to Hep G2 Compared with free DOX and DUN.Conclusion:The prepared MIL-101（Fe）-NH₂and UIO-66-NH₂nano metal organic framework materials have stable structure and uniform size.The anticancer drug doxorubicin（DOX）was successfully encapsulated in NMOFs to prepare DMN and DUN nano-drug carrier systems.Using HA to modify the nano particles to obtain DMNH and DUNH composite-nano-drug-carrying systems,which gives the carriers tumor targeting.The results show that the drug release rates of DMNH and DUNH are both time-and p H-dependent.Due to the HA modification on the surface,DMNH and DUNH have advantages in cell uptake.Due to the CD44 receptor-mediated targeting effect,the DMNH and DUNH showed a stronger tumor suppressor effect than the other groups.The prepared nano-drug carrier systems DMNH and DUNH show great potential in p H-responsive drug delivery.