The Preparation Of Upconversion Nanoparticles And Their Bio-medical And Environmental Application

Upconversion nanoparticles （UCNPs）, as a new type of luminescent materials, havearoused people’s wide concern due to their unique optical properties. The UpconversionLuminescence’s study on rare earth ions has shifted the focus from the initial stage ofpreparation to the stage of application developments; grown from the initial application inthe field of optics to areas such as biomedical and environmental testing. The modifiednanoparticles, as fluorescence probes, are applied into aspects such as biomarkers,biological imaging and drug delivery. Furthermore, UCNPs nanoparticles based onupconversion nanoparticle’s fluorescence resonance energy transfer （FRET） system, hasfulfilled its function as a method on detection of environmental pollutants. The detailedresults are as follows：(1) By using characterization methods including XRD, SEM, Fluorescence spectr（FL）and TEM, do research on UCNPs’ morphology, size and optical properties underdifferent reaction conditions, to obtain an optimal reaction parameter.(2) Modify UCNPs using porous Silicon, to improve the hydrophilic andbiocompatibility of the nanoparticles. Conducting cell experiments with modifiednanoparticles as fluorescence probes, and drug carriers, and finally obtain a clear photoimaging and maximum drug loading capacity of0.156mmol/g, maximum drug release’srate of70%, in the acidic microenvironment.(3) Prepare the UCNPs with thermal decomposition method, and absorb RhodamineB hydrazide （RBH） by hydrophobic interactions, constructing the FRET formed bynanoparticles as the donor, and Cu2+with Rhodamine B hydrazide’s complexation as thereceptor. Achieved the quantitative detection of copper ions, based on the ultravioletabsorption enhancement of the receptor and the fluorescence quenching of the donor.To sum up, we can obtain successfully NaYF4nanoparticles with features likecontrollable morphology, uniformed particle size and sound luminescence properties, byadopting the optimum reaction parameters. The modification with porous Silicon onnanoparticles, improving the water solubility and biocompatibility, allows the nanoparticles to be widely used in fields such as biomedical and environmentalmonitoring as fluorescence probes.