Preparation Of Long Lasting Nanoparticle And The Application In Bioimaging

Long afterglow nanoparticles have a great number of advantages such as low toxicity,relatively high chemical and optical stability, narrow emissions bond, as well as long lifetimeemission. In addition, external excitation is the unique advantage of long afterglow, which canavoid the effect of autofluorescence of biological tissues and thus result in high radio to noise.Therefore, long lasting nanoparticles have been regarded as potential probes in vivo imaging.However, since optical imaging suffers from low tissue penetration and low resolution, moreand more researches focused their attentions on the development of multifunctionalnanoprobes. The integration of optical and magnetic resolution imaging provides a newapproach to bridge the gap in resolution, sensitivity, and depth of imaging by combining thesetwo modalities. Thus, we designed the novel multifunctional nanoprobes long afterglownanoparticles containing gadolinium and magnetic iron oxide in order to enhance the highsensitivity.There are three parts in this thesis. The first section is preparation of core-shell structureGd₂O₃@mSiO₂@CaTiO₃:Pr and their application in optical imaging, magnetic resolutionimaging and drug delivery. The second section is preparation of Ca₂Gd₈（SiO₄）₆O₂:Eu,Dy,Mnwith Gd₂O₃@mSiO₂as template and their application in optical imaging and magneticresolution imaging; The third section is preparation of core-shell structureFe₃O₄@mSiO₂@CaTiO₃:Pr with the Fe₃O₄@mSiO₂as template.1Gd₂O₃@mSiO₂@CaTiO₃:Pr nanoparticles were prepared using Gd₂O₃@mSiO₂astemplate. The morphology and size of nanoparticles are unniform. The long afterglowemission of these nanoparticles can persist more than one hour and their phosphorescentsignal is sufficient to detect the obvious signal of the nanoparticles in at least40minutes inluminescence imaging. With the concentrations increasing from0to0.3mM, the T₁-weightedimages gradually became brighter, which answers for positive enhancement of the effect onT₁-weighted sequences. The nanoparticles have a concentration-dependent protonlongitudinal relaxivity （r1） of6.43mM s^-1on the0.5T scanners. The cumulative release ofIBU firstly is raipd within the starting20hours and then followed by a sustained release until90hours, and reached about73%in the whole process.2Ca₂Gd₈（SiO₄）₆O₂:Eu,Dy,Mn nanoparticles were prepared using Gd₂O₃@mSiO₂astemplate. The morphology and size of nanoparticles are uniform. The long afterglow emissionof these nanoparticles can persist more than one hour and their phosphorescent signal is sufficient to detect optical signal of the nanoparticles in at least30minutes in luminescentimaging. With the concentrations increasing from0to0.3mM, the T₁-weighted imagesgradually became brighter. This can be attributed to positive enhancement of the effect onT₁-weighted sequences. The nanoparticles have a concentration-dependent protonlongitudinal relaxivity （r1） of4.13mM s^-1on the0.5T scanners.3Fe₃O₄@mSiO₂@CaTiO₃: Pr red long afterglow nanoparticles were prepared usingFe₃O₄@mSiO₂as template. As the high calcination temperature of800oC, there existedslightly deformed, sintering and aggregation of nanoparticles. The long afterglow emission ofthese NPs can persist about20minutes.