Preparation And Application Of Functional Organosilica Nanomaterials

Organosilica nanomaterial is a new type of organic-inorganic hybrid material.The main structure is-Si-O-Si-as the network skeleton,and organic groups are dispersed in it through the covalent bonds with silicon atoms.The organic groups distributed in the materials can also change the properties of the materials and provide unique function for the nanomaterial,such as biodegradable,fluorescence,phosphorescence and oxidation-reduction properties.Therefore,the functional organosilica nanomaterials become a research hotspot in the field of biomaterials.However,because of the negative potential of the framework of functional organosilica nanomaterials and the particle size that is large than 50 nm,the endocytosis efficiency of the organosilica nanomaterials is low.Meanwhile,the synthesis process of organosilica nanomaterials often require high temperature and emulsifiers,which will also reduce the biosafety of organosilica materials.Therefore,this paper focuses on the synthesis of multifunctional organosilica nanomaterials with small particle size through the modification of functional materials and radiation method,and the application of organosilica nanomaterials in gene transfection,cancer treatment and anti-counterfeiting coating.The main research contents and results are as follows:1.Novel glutathione(GSH)-triggered degradable organosilica nanoparticles with guanidinated-fluorinated ?-polylysine(PLL)grafted on the surface(o-SiNP-GF)are prepared.The organosilica matrix of the nanoparticles is synthesized through the hydrolysis and condensation of 1,2-bis(triethoxysilyl)ethane(BTSE)and bis[3-(triethoxysilyl)propyl]tetrasulfide(BTSPTS).The o-SiNP-GF nanoparticles have a size of about 20 nm and a positive zeta potential of 42 mV in PBS.They can disintegrate in the PBS containing GSH(10 mM).We found that o-SiNP-GF is a better gene transfection reagent than traditional one in biological safety,cell endocytosis efficiency,and DNA binding ability.The transfection efficiency ofpEGFP/o-SiNP-GF complexes in vitro and in vivo has been studied and compared it with pEGFP/polyethylenimine(PEI)complexes.The result proves that pEGFP/o-SiNP-GF complexes have higher gene transfection efficiency than that of pEGFP/PEI.2.A simple synthesis of Zn-o-SiNP by y-ray radiation in the aqueous solution of APTES and zinc nitrate is presented.Zn-o-SiNP possess a positive zeta potential of 57 mV in PBS,they have a small size less than 50 nm,and can emit strong and tunable fluorescence.The cytotoxicity and DNA-binding ability of Zn-o-SiNP,as well as in vitro and in vivo gene transfection performance of DNA/Zn-o-SiNP complexes,have been investigated using enhanced green fluorescent protein plasmid(pEGFP)as the DNA model.We prove that pEGFP/Zn-o-SiNP complexes have low toxicity and stable structure,the gene transfection efficiency of pEGFP/Zn-o-SiNP complexes also keep in high level.3.A new type of copper(?)-organosilica nanoparticle(Cu+-SiNP)is designed and prepared.When 3-mercaptopropyltriethoxysilane hydrolyze and condense in water,the sulfydryl and Cu2+ generate the disulfide bonds and Cu+ through the redox reaction.Cu+is a highly effective Fenton reagent that can react with H2O2 to generate hydroxyl radicals for cancer treatment.The complexes of thiol groups and Cu+ in the nanoparticles protect Cu+from oxidation,and can emit red fluorescence under the excitation of ultraviolet light.Therefore,this work reports the excellent nanoparticles for the integration of fluorescence imaging and cancer therapy.4.Phosphorescent silica nanoparticles(p-SiNP)are obtained by calcination at 650? of fluorescent nanoparticles which synthesized by y-ray irradiation of 3-aminopropyltriethoxysilane(APTES)and Zn2+.The size of the p-SiNP is about 150 nm.The nanoparticles emit blue fluorescence under the excitation light of 365 nm,and they will emit green phosphorescence when the light source is turned off.The phosphorescence lifetime can be effectively extended by increasing the calcination time.The p-SiNP can be directly mixed with silica sol and solidified to form a thin film,and form a phosphorescent pattern on it.The coating containing p-SiNP can be used in the application of anti-counterfeiting.