Preparation And Properties Of Rare Earth-Folate Coordination Polymer Ultra-microsphere Materials

Folic acid（FA）is a targeting molecule that can be internalized by a folate receptor（FR）and enters the cytoplasm through FR-mediated endocytosis to achieve drug action.It is suitable for a large number of human cancer cells with overexpressed folate receptor（FR）,so FA is a tumor-specific targeting molecule with poor biocompatibility and poor immunogenicity to normal cells.Rare earth coordination polymer,as a material that has been particularly favored in various application fields,has properties that are unmatched by many other materials.One of its main application fields is luminescent material,which not only has down conversion luminescence properties but also has a high efficiency up-conversion luminescence properties.In order to improve the targeting of rare earth coordination polymers and reduce the toxic and side effects of drugs,FR can be used to actively target rare earth coordination polymers to target organs or target cells to achieve folic acid-rare earth coordination polymers（RE-FACP）active targeted transportation.There is little research on rare earth coordination polymers using FA as a ligand.Therefore,in order to achieve the effects of targeted imaging and targeted drug delivery,the work presents a series of methods and ideas for the synthesis of rare earth coordination polymers.（1）Preparation and properties of Eu-FACP ultra-microsphere with down-conversion properties.When FA is used as the organic crosslinking ligand and rare earth europium ions are used as metal ions,the reaction time,reaction temperature,and coordination ratio of the ligands and ions are obtained by the mixed solvent method to obtain a uniform shape,excellent dispersion particle size and well-dispersed europium-based folic acid coordination polymer（Eu-FACP）with a particle size of 100-200 nm,Eu-FACP characterizes the morphology and structure of materials by SEM,TEM,XRD,etc.At the same time,its performance is investigated for it’s luminescence imaging,biological toxicity and targeted imaging capabilities,Experimental research shows that Eu-FACP is a hollow ultra-microsphere with a particle size of about 200 nm,which has great biocompatibility and fluorescence intensity.It is co-cultured with MCF-7 cells.It can be found that it has a good targeted luminescence ability.From this,it can be seen that folic acid can still play a targeting role after coordination with europium ions.This research can provide ideas and references for composites that target rare earths to target cancer tissues.（2）Preparation and properties of Y-FACP ultra-microsphere with up-conversion properties.On the basis of the above research,because biological tissues have obvious absorption of light in the visible light region,and the up-conversion material can achieve the ability to convert near-infrared light into visible light,When FA is used as the organic crosslinking ligand,rare earth yttrium ions are used as metal ions and doped with ytterbium ions(Yb³⁺)and erbium(Er³⁺)ions,Rare earth yttrium ions are metal ions and doped with erbium and ytterbium ions to form uniform size and good dispersion.The particle size is converted to ultra-microsphere on ytterbium-doped yttrium base with a particle size of 100-200 nm（Y-FACP）,Through a series of experimental investigations to obtain the best doping ratio and best fluorescence intensity,and to explore its biological toxicity and drug loading capacity,Folic acid and yttrium ions(doped withYb³⁺,Er³⁺)to form coordination polymers,FA-YCP is a hollow microspheres with a particle diameter of about 100 nm-200 nm,which has good cytotoxicity and fluorescence intensity.At the same time,it can be found to have great drugs loading of with doxorubicin（DOX）.Load capacity,and in view of its light-emitting ability and the particularity of the excitation light source,this study can provide ideas and reflections for the synthesis of up-conversion drug-loaded coordination polymers.（3）Preparation and properties of multifunctional Gd-FACP ultra-microsphere.Through exploration and experimentation,rare earth Gadolinium ions are metal ions,doped with ytterbium ions(Yb³⁺)and erbium(Er³⁺)ions,and folic acid is used as an organic ligand to form a homogeneous morphology and well-dispersed Gadolinium-Based Coordination Polymer（Gd-FACP）.Through SEM,EDS,TEM,XRD,FT-IR and other characterization results show FA and Gadolinium ions(doped with Yb³⁺,Er³⁺)form up-converted ultra-microsphere with a particle size of200 nm.It has a certain up-conversion fluorescence intensity.At the same time,its cytotoxicity and drug loading capacity are also investigated.The results show that it has a good drug loading capacity.