Preparation Of Organic/Inorganic Hybrid Phosphor Nano Probe And Application

Rare earth elements and their complexes exhibit relatively long lifetimes and large Stokesshifts which easily separating of excitation and emission and could be used as promising candidatesfor fluorescence probes. Although rare earth elements and their complexes possess excellent phot-ophysical properties, they have some drawbacks for biological applications since their poorsolubility in aqueous solutions, no visible absorption and toxicity. Also, the biologicalenvironmental impacts their optical function. Therefore, it is necessary to select another complexesto promote their absorbance at visible region, and the appropriate method to solve theirhydrophilicity. Due to the unique properties of high quantum efficiency, long lifetimes and visibleabsorption, phosphorescent heavy-metal [Ir(III)] complexes have been selected as the energy donorsto sensitize rare earth elements and their complexes(as the energy receptors). Meanwhile, in virtueof the unique properties of adjustable pore diameter, high surface area, large pore volume,easysurface modification, non-toxicity and biocompatibility, the mesoporous silica nanoparticles (MSN)has been as carrier used in many biological fields.Herein, the complexes of Eu(TAA)3(apt) and Ho(TAA)3(apt) have been synthetized as theenergy‘s receptors, and the complexes of iridium (III) complexes with different emission weredesigned and synthesized as the energy donors. Then through the reaction of amino in N^N ligandand3-(triethoxysilyl)propyl isocyanate, Ir(III) and Eu(III)/Ho(III) complexes were conjugated intosilica framework, and emission tunable mesoporous silica nanoparticles (MSNs) were prepared.This MSNs with low cytotoxicity does not affect the luminescence properties of complexes, and canbe as probe for cell imaging and time resolved imaging.Herein, in the system of Ir1@Eu@MSNs, Ir1@Eu@SSNs and Ir2@Eu@MSNs, thecharacteristic emission peaks from Eu3+can be observed under the irradiation of visible lightthrough energy-transfer process, and the excitation range contain458-488nm. Comparison offluorescence intensity of Ir1@Eu@MSNs’ and Ir2@Eu@MSNs’, we can draw the followingconclusion: the complex of Ir1is better than Ir2to sensitize Eu3+. This may be attributed to thetriplet state energy difference between Ir1and Ir2to Eu complex. Cell imaging showed thatIr@Eu@MSNs can stain living cell as nanoprobe with low cytotoxicity. Furthermore, time resolvedimaging in cells have also been achived using Ir@Eu@MSNs as probe. The findings demonstratedthat this kind of nanomaterials are promising candidates as phosphorescent nano-probes for bio-imaging.We further synthesized Ir2@Ho@MSNs composites. In this nanosystem, Ho complex can besensitized by Ir2complex under the irradiation of visible light through energy-transfer process, andpresent characteristic emission of Ho from visible and near-infrared region. These features makethem highly suitable as luminescent labels for bioimaging, especially in vivo imaging.