Controlled Doping Of Dye In The Silica Nanoparticles And Study Of Their Properties

Biolabeling is needful to be used in medicine research and clinicaldiagnosis for monitoring the cells activities and recognition and expressing thedistribution of biomolecules in vitro or vivo and metabolism of livingorganism. With the development of study for life especially in gene andprotein research, biolabeling technology is faced new challenges andrequirements.Due to specialty and complex of biological system, luminescent probe ishighly demanded for detecting life nature. They are high photo stability and nophotobleaching, low toxicity , good excitation and emission efficient, highsensitivity to biological activity, obvious spectra character and so on. As amatrix material for luminescent probes, silica provides a chemically andmechanically stable vehicle, which can protect the encapsulated dye moleculesfrom external perturbations, while exposing a biocompatible and easilyfunctionalized surface to the environment and in some cases enhancing thephotophysical properties of the encapsulated dyes.However, poor controlled doped method lead to unmultivariateluminescent properties and low chemical stability. And less repeatability ofpreparation greatly limits the applications of these materials. On the basis ofstudy for interaction between dye molecules and silica matrix, we systemically study internal relationship of architectures of dye doped silica nanoparticlesand properties and build controlled method through changing doped processand particles structure. The obtained dye doped silica nanoparticles can beused for immunoassay and biolabeling application with high sensitivity. At last,after combination of adjust in doping method and component of colourometryRGB luminophors, in is feasibility to achieve color coding and high throughout detections.In chapter 2, we show that the Ru(4,7Ph2phen)3 doped silica nanoparticles from St?ber method present ultralonglifetime of phosphorescence emission after the shell growth and dense liquid treatment. Itis identified that shell growth is effective to suppress the nonradiative decayprocess from 3MLCT excited states by shielding the doped dye from solventeffect, and dense liquid treatment is supposed to provide steric constraints forthe doped dye, thus leading to decreased deactivation of the thermallypopulated 3dd (ligandfield)states. Right combination of Stober method anddense liquid treatment results in Ru(4,7Ph2phen) 3 doped silica nanoparticleswith average lifetime as long as 17.69μs. They make the bioassays moreprecise by distinguishing the intrinsic background fluorescence ofbiomolecules in a timeresolvedway.In chapter 3, through changing ammonia concentration to adjust growthprocess of silica particles, we study the effect of different interaction processof silica particles on the luminescent properties of the dye doped silicananoparticles. The experiments demonstrate that the quantum yield of theparticles decrease gradually with the increase in ammonia concentration due tothe extent of dye aggregation in the silica nanoparticles increased. It is becausein the nucleation process, the more ammonia concentration results in thesmaller number of primary particles. Thus the more dye can accumulated on the particles. In the subsequent growth process, the aggregate proceedsbetween the primary particles are controlled by cooperation effects of ionstrength effect induced by ammonia and the stability of the primary particlesinduced by dye adsorption. So the quantum yield and emission wavelength aredecreased and red shift gradually with increased ammonia concentration.In chapter 4, on the basis of relationship between silica architecture andluminescent properties, we synthesize the dye doped silica nanoparticles withdifferent doped structure by changing concentration ratio of dye and TEOS.When the concentration ratio is high, the dye aggregations distribute in the allof the core and shell silica layer. While the concentration ratio is low enough,the dye molecules are only loaded in the core homogeneously and coated bythick silica shell. The experiment results indicate that the relativeconcentration of dye concentration and primary silica particles decides thegrowth modal of silica nanoparticles. High dye concentration can lead tocontrolled aggregate between primary silica particles by reducing the colloidalstability of the particles, and low dye concentration results in growth modal ofmonomer addition because of little dye molecules adsorption on the primaryparticles. When further dense liquid treatment on the dye doped silicananoparticles with homogeneous dye distribut ion and thick silica shellprotection, the little solvent effect on the luminescent properties and emissionintensities are increased strongly. So the obtained dye doped silicananoparticles can provide a much improved efficiency for the cell labelingcompared to the pure dyes. Moreover, extend 48 h incubation experimentsreveal that there is no deleterious effect of the nanoparticle on cell viability .And the dye doped silica nanoparticles with the highest quantum yield can alsobe used for immunoassay application and show a good line relation and highsensitivity. In chapter 5, hydrophobic octadecyloxycoumarin doped silicananoparticles by cation CTABdirect template modified Stober method. Theproper CTAB in the ethanol/water mixture can format stability micellestructure, which has oil phase to disperse hydrophobic dye and hydrophilicpositive charge group to electric adsorption on the silica. The coumarin dopedsilica particles maintain the high blue fluorescent intensity and no dyebleaching from happen. On the other hand, Ru(phen)3 molecules of redluminescent and FITC of green fluorescence are codopedin silica through interacting of static adsorption and covalence, respectively . Controlling thethickness of silica layer between two dyes and relative concentration of twodyes, the multicolor particles emit high luminescent intensity and a wide rangeof luminescence. Combination of adjust in doping method including covalence,static and hydrophobic interaction and component of colourometry RGBluminophors, we will build highly integrated''lab on a particle''architectureswith multicolor emission by single wavelength excitation.