Study On The Preparation Of Functional Nanomaterials And Their Application In In Vivo Fluorescence Imaging

Real-time, accurate observation of life activities in vivo needs of variousnon-invasive imaging methods. The in vivo fluorescence imaging has been widely usedin the research field of life sciences, medical research and drug development becauseof its unique advantages, such as simple operation, intuitive results, and sensitivitycharacteristics and so on. In recent years, functional nanomaterials are widely used inimaging. Especially the development of nanomaterials with biocompatibility, bettertargeting and excellent optical propertiesor fluorescence imaging in vivo has veryimportant significance. Aiming at the development of functional nanomaterials for invivo fluorescence imaging, the research on the preparation of new fluorescentnanomaterials and their application in fluorescence imaging in vivo are carried out inthis thesis. The three parts of the thesis are as follows.1. Study on the passive tumor targeting in vivo fluorescence imaging usingdifferent functional groups modified silica fluorescent nanoparticlesAfter the three different functional groups modified fluorescent silicananoparticles, including hydroxyl-SiNPs, carboxyl-terminated SiNPs (COOH-SiNPs)and polyethylene glycol (PEG)-terminated SiNPs (PEG-SiNPs), has been prepared byusing reverse microemulsion method, the passive tumor targeting in vivo fluorescenceimaging has been investigated. Using Ramos and CEM tumor xenograft models, invivo and ex vivo imaging studies showed that the three different functional groupsmodified fluorescent silica nanoparticles were able to quickly accumulate in the tumorarea, thanks to passive tumor targeting after injection via the tail vein. Therefore, theycan be used as fluorescence imaging probes. In addition, PEG modified silicananoparticles make it possible for a long time imaging.2. Study on the preparation of upconversion nanomaterialsWe prepared rare earth ions doped sodium yttrium fluoride crystals byhydrothermal synthesis. The effects of different reaction conditions on the synthesis ofsuch nanomaterials have been investigated. The results showed that both oleic acid andPEI complexing agent can be used as templates to successfully synthesizeupconversion nanomaterials. By comparasion, the upconversion nanomaterialssynthesized by using oleic acid as template displayed higher fluorescence intensity.Furthermore, the complexing agent, reaction time, reaction temperature, the amount of fluoride and rare earth ion ratio and other experimental conditions would change theshape, size, fluorescence intensity and spectral properties of the crystal when oleicacid was selected as template to synthesize the upconversion nanomaterials..3. Study on the in vivo fluorescence imaging using upconversion nanomaterialsAfter screening the excellent condation for preparing the upconversionnanomaterials in Charpter2, the PEG modified upconversion nanomaterials wereprepared using oleic acid as template. Subsquently, the biocompatibility andapplication of the prepared PEG modified upconversion nanomaterials in fluorescenceimaging in vivo were carried out. Through the body weight change analysis, resultsdisplayed that the body weight of the mice administrated with the upconversionnanomaterials has not been changed obviously. And we found that this material can beused in subcutaneous and muscle imaging, and whole body imaging, without interffingof the autofluorecence. The results indicate that the prepared upconversionnanomaterials appear as very promising contrast imaging agents with high penetrationand high-contrast.