| With the progress of nanotechnology, nanomaterials have been made broad research and application in biomedicine. Recent advances in nanomedicine have heightened the demand for new therapies and coherent implementation applications for the integration of medical diagnostics, drug delivery and efficient therapy (therano sties) into a single structured nanoplatforms.Rare earth upconversion nanoparticles (UCNPs) are able to emit the spectra from ultraviolet (UV) to near infrared reflection (NIR) under excitation by near-infrared (NIR) light, which possess a range of unique properties, such as tunable emission, high photostability, low cytotoxicity, and importantly, little background auto-fluorescence and low damage to cells and tissues making them attractive agents in biomedical imaging and detection. Benefiting from the significantly improved physical, chemical, and biological properties, UCNPs will also bring new changes and rapid development to multifunctional nano-materials for bio imaging and simultaneous diagnosis and therapy.In this thesis, we further explore the applications of UNCPs and their nano-composites in tissue engineering and optical-guide drug delivery. Monodispersed rare earth doped Perovskite (CaTiO3 and SrTiO3) nanoparticles with narrow size distribution, good crystalline property and high luminescent intensity are firstly synthesized by different methods. Then CaTiO3:Yb3+,Er3+@ Bioactive Glass (CaTiO3:Yb3+,Er3+@BG) nano fibers are synthesized to optically monitor the mineralization of bioactive glasses in body fluid. Moreover, SrTiO3:Yb3+,Er3+@mSiO2.are prepared by coating mesoporous silica shell onto the SrTiO3:Yb3+,Er3+ nanoparticles as drug carrier. Based on this, we can expediently monitor the drug loading and release process by upconversion luminescent. The specific contents are as follows:Chapter 1:The first part briefly describes the nanomaterials used for biomedicine, especially the properties and applications of rare earth upconversion luminescent nanoparticles. Also, the advantages and preparation methods of UCNPs with perovskite matrix.Chapter 2:The summarize of the raw materials for experiments and the analysis methods, such as XRD, FTIR, S EM and so on.Chapter 3:Preparation of UCNPs by different methods. The nanoparticles are obtained by sol-gel process, but with severe aggregation because of the high temperature annealing. Then CaTiO3:Yb3+,Er3+ nanoparticles for about 60nm with narrow size distribution are synthesized by co-precipitation method. EDTA contributes much in the control of crystal grow and aggregation Further, monodispersed SrTiO3:Yb3+,Er3+ nanoparticles are prepared by the modified LSS method with the diameter of ～100nm. All these nanoparticles possess good upconversion luminescent properties.Chapter 4:In order to prove a facile method of detecting the various changes in tissue engineering, complex nanofibers are fabricated by combining the CaTiO3:Yb3+:Er3+ with bioactive glass (CaTiO3:Yb3+,Er3+@BG) by electrospinning. The UC PL intensity is quenched during the bone-like apatite formation in simulated body fluid (SBF). Such results make it possible to optically monitor the bone regeneration and scaffold degradation in bone tissue engineering.Chapter 5:A range of monodispersed core-shell structured photo luminescent SrTiO3:Yb3+,Er3+@mSiO2 nanoparticles were designed and synthesized as the new type of drug carrier with great biocompatibiliy. Surfactant cetyltrimethylammonium bromide (CTAB) was used to vary the microstructure of the mesoporous SiO2 shell. We further discuss the drug loading capacity and release kinetics for a period of time. More importantly, DOX releasing kinetics was found to correspond well to the evolution of the up-conversion luminescence (UCL) phenomenon. This study has therefore been anticipated to suggest a promising multifunctional drug delivery platform for advanced chemotherapies.Chapter 5:We give conclusions of these researches and discuss the remaining problems which may need further study. |
PDF Full Text Request