Preparation And Bioapplication On Rare Earth Fluorides Nanomaterials

Rare-earth fluorides have attracted considerable interest due to their unique luminescence properties.Rare-earth fluorides exhibit superb photostability,chemical stability and biocompatible,thus making them applicable to bioimaging,biochemical probing and drug delivery.In this dissertation,we mainly research the preparation and application of NH₄Eu₃F₁₀,NaYF₄:Yb³⁺/Er³⁺and NaGdF₄:Yb³⁺/Er³⁺nanoparticles.We explored the synthetic method,studied the formation mechanism,found out the influence of reaction conditions on the structure,morphology and particle size of products,and further used the as-obtained nanoparticles for bio imaging and drug delivery.This thesis mainly includes three parts as follows:?1?Cubic phase NH₄Eu₃F₁₀ nanospheres with controllable sizes were synthesized via a modified hydrothermal route by varying the dosage of ammonium hydroxide solution.Dependence of structure and morphology on the dosage of ammonia water and reaction time were investigated by X-ray powder diffraction?XRD?and transmission electron microscopy?TEM?.Being unstable,NH₄Eu₃F₁₀ decomposed into EuF3 and NH4F during the long-time hydrothermal treatment.EDTA,as the chelatiol agent of Eu³⁺ and the Capping ligand on the surface of as-obtained nanospheres,showed different chelating abilities depending on the dosage of ammonium hydroxide solution.Increasing the amount of ammonia not only decreased the effective concentration of Eu³⁺,but also decelerated the growth of NH₄Eu₃F₁₀ nanospheres and stabilized them by reducing the surface energy.Given the satisfactory hydrophilicity,biocompatibility,and luminescence,the as-obtained nanospheres were applied as promising agents for cell?2?Herein,we synthesized carboxyl polymer-coated NaYF₄:Yb³⁺/Tm³⁺nanoparticles through a hydrothermal route during which methacrylic acid polymerized and bound to the surface of the nanoparticles.Dependence of structure and morphology on the dosage of NaOH was investigated by XRD and TEM.The polymerization degree of poly?methacrylic acid?and the amount of capping carboxyl group influenced by the dosage of NaOH were also studied.Other carboxyl-functionalized rare-earth fluorides could be obtained by using this method,the mechanism for which was also investigated.cis-Dichlorodiammineplatinum????cisplatin,CDDP?-loaded NaYF₄:Yb³⁺/Tm³⁺nanoparticles?NaYF₄-CDDP?were characterized by energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy,and CDDP was loaded in the form of Pt-O bonds.Upconversion luminescence images revealed the time course of intracellular CDDP delivery by NaYF₄-CDDP.Compared with CDDP alone,NaYF₄-CDDP composite exerted cytotoxic effects on HeLa and MCF-7 cancer cell lines depending more on time and more slowly due to time-dependent cellular uptake and drug release.Non-loaded NaYF₄:Yb³⁺/Tm³⁺ nanoparticles were also eligible for upconversion luminescence cell imaging.?3?NaGdF₄:Yb₃D/Er³⁺ nanoparticles were synthesized via a modified hydrothermal route.Dependence of structure and morphology on the dosage of sodium polyacrylate was investigated by XRD and TEM.The as-prepared nanoparticles could be used for magnetic resonance imaging.CDDP was loaded onto the surface of NaGdF₄:Yb³⁺/Er³⁺nanoparticles through binding carboxyl in the form of Pt-O bonds,and DOX was loaded via electrostatic interaction of hydrogen bond.DOX could be also loaded to NaGdF₄-CDDP through the same way,while the loading efficiency of both drugs remaining unchanged.Three as-prepared drug delivery systems were used for tumor inhibition both in vitro and in vivo,and the results indicated that NaGdF₄-CDDP-DOX showed better therapeutic effect.