Preparation Of Porous Silica Nanoparticles And Their Applications

ObjectiveThe purpose of this paper was to prepare porous SiO₂ nanoparticles with large specific surface area and good biocompatibility.The prepared porous SiO₂nanoparticles were used as adsorbents to adsorb organic dyes and their adsorption properties were explored.Porous SiO₂ nanoparticles and sodium alginate composite microspheres（SiO₂@SA）were used as drug carrier loaded with antioxidant drug tea polyphenols（TP）to investigate the drug loading properties of SiO₂@SA microspheres and their effects on the proliferation and differentiation of osteoblasts.MethodsIn the ethanol-water solvent system,tetraethoxysilane（TEOS）was used as the silicon source to prepare SiO₂ nanoparticles under the catalysis of ammonia water,and then the porous SiO₂ nanoparticles were prepared by the etching of sodium hydroxidelye.In the experiment of investigating the adsorption properties of porous SiO₂ nanoparticles,organic cationic dyes alcian blue（AB）,methylene blue（MB）and anionic dyes congo red（CR）,coomassie brilliant blue（CB）solutions were used to simulate dyes wastewater.The effects of different factors on the adsorption properties of porous SiO₂ nanoparticles were investigated.In addition,pH-sensitive TP@SiO₂@SA@CaCO₃ hydrogel microspheres were formed by SiO₂@SA composite hydrogel microspheres encapsulated the anti-oxidant drug tea polyphenols（TP）.The release behavior of TP@SiO₂@SA@CaCO₃hydrogel microspheres was investigated under pH=7.4 and pH=5.5 conditions.The morphologies ofnanoparticles and TP@SiO₂@SA@CaCO₃hydrogel microspheres were investigated byscanning electron microscopy（SEM）and transmission electron microscopy（TEM）.The componentsofnanoparticlesandTP@SiO₂@SA@CaCO₃hydrogelmicrospheres were detected by Fourier Transform Infrared spectroscopy（FTIR）.The crystalline phase of nanoparticles was detected by X-ray diffraction（XRD）.The absorption spectroscopies of the adsorbed dyes and the loaded TP were tested by UV-vis.Results（1）The obtained porous SiO₂ nanoparticles have a good morphology with an average diameter of³70nm.The obtainedTP@SiO₂@SA@Ca CO₃hydrogel microspheres have a rough morphology with an average diameter of⁴ mm.（2）It is known that organic cationic dyes AB and MB hadbeen successfully adsorbed by porous SiO₂ nanoparticles as well as tea polyphenols have been successfully encapsulated in TP@SiO₂@SA@CaCO₃ hydrogel microspheres from the results of Fourier Transform Infrared spectroscopy and UV-vis absorption spectroscopy.（3）The adsorption efficiency of porous SiO₂ nanoparticles on AB and MB were 99.71%and 99.06%,respectively,and the adsorption capacity was 250mg/g and 160 mg/g,respectively.The results of the recycle experiment（calcining method）indicated that porous SiO₂ nanoparticles could be recycled at least 6 times.The obtained TP@SiO₂@SA@CaCO₃ hydrogel microspheres had a drug DLE of 92.96%and DLC of 19.62 wt%.（4）In in-vitro released experiment,the release amount of TP was only 12.9%from TP@SiO₂@SA@CaCO₃ hydrogel microspheres at pH=7.4 after dialysis for 6 h.At pH=5.5,it reached 42%after dialysis for 1 h,nearly 100%within 6 h.（5）InMTTassay,theconcentrationofTPin TP@SiO₂@SA@CaCO₃hydrogel microsphereswas 2.0 mM,osteoblast cell viability increased to 80.3%at pH=5.5.Conclusions（1）The prepared porous SiO₂ nanoparticles had high adsorption efficiency and adsorption capacity for cationic organic dyes,and could be recycled several times after removing adsorbed dyes by calcination.As an efficient and recyclable adsorbent,the treatment of organic dye contamination had a certain application prospect.（2）ThepreparedTP@SiO₂@SA@CaCO₃composite hydrogelmicrospheres had an acidity response property and gradually degrade under the condition of pH=5.5,releasing encapsulated anti-oxidant drugs tea polyphenols,and effectively promoted the proliferation and differentiation of osteoblasts.