The core-shell Fe2O3@Au particle with spindle morphology were synthesized by three steps.The mean size of the core-shell paricles was about 500 nm by 85 nm.The final single separated spindle particles were attached on...The core-shell Fe2O3@Au particle with spindle morphology were synthesized by three steps.The mean size of the core-shell paricles was about 500 nm by 85 nm.The final single separated spindle particles were attached onto Si substrates.The thiophenol(TP) was served as probe molecule to investigate the pola-rized dependent surface-enhanced Raman scattering(SERS) from single particle.Dramatic variations in SERS intensity was observed when the single core-shell particle was oriented at different angles relative to the polarization of excitation laser.The maximum SERS intensity was detected for TP absorbed on the anisotropic particle which was in the polarization direction parallel to the long axis of the particle,while the minimum intensity was detected at the direction of the incident field that is perpendicular to the long axis of the particle.Our preliminary results provided useful way for obtaining deeper insight to the SERS mechanism.展开更多
针形铁黄纳米粒子表面包覆无机物如Si、Co等氧化物形成复合纳米粒子,是改善金属磁性记录粉性能的重要方式.采用ICP,TEM,XPS方法研究复合纳米粒子的表面性质,结果表明包硅复合粒子的表面形成均匀、致密的SiO2薄膜,表面层与基体表面间的...针形铁黄纳米粒子表面包覆无机物如Si、Co等氧化物形成复合纳米粒子,是改善金属磁性记录粉性能的重要方式.采用ICP,TEM,XPS方法研究复合纳米粒子的表面性质,结果表明包硅复合粒子的表面形成均匀、致密的SiO2薄膜,表面层与基体表面间的界面结构类似异质结,导致粒子的XPS谱图中 Fe 2p谱峰发生2.7eV的化学位移;而包钴复合粒子由于钴在铁黄表面的吸附发生在部分晶面上而无法形成均匀、致密的薄膜,XPS谱图主要发生因表面荷电而导致的物理位移.展开更多
In this paper,chemical co-precipitation method was employed to synthesize Fe3O4 nanoparticles which can be well dispersed in water by using citric acid as a surfactant.Afterwards,by using Fe3O4 nanoparticles as seeds ...In this paper,chemical co-precipitation method was employed to synthesize Fe3O4 nanoparticles which can be well dispersed in water by using citric acid as a surfactant.Afterwards,by using Fe3O4 nanoparticles as seeds in a Triton X-100/hexanol/cyclohexane/water reverse microemulsion system,the core-shell structural Fe3O4@SiO2 nanocomposite particles were prepared via hydrolysis and condensation of tetraethyl orthosilicate(TEOS) under the catalysis of alkali.The effects of different stirring methods and the concentration of TEOS on the morphology of Fe3O4@SiO2 nanoparticles were investigated.The results show that the mechanical stirring can effectively control the morphology of composite nanoparticles to form a good dispersion and spherical morphology of core-shell nanoparticles.With the increase of TEOS concentration,the thickness of the SiO2 shell increases,and the morphology of the composite particles becomes more uniform.展开更多
文摘The core-shell Fe2O3@Au particle with spindle morphology were synthesized by three steps.The mean size of the core-shell paricles was about 500 nm by 85 nm.The final single separated spindle particles were attached onto Si substrates.The thiophenol(TP) was served as probe molecule to investigate the pola-rized dependent surface-enhanced Raman scattering(SERS) from single particle.Dramatic variations in SERS intensity was observed when the single core-shell particle was oriented at different angles relative to the polarization of excitation laser.The maximum SERS intensity was detected for TP absorbed on the anisotropic particle which was in the polarization direction parallel to the long axis of the particle,while the minimum intensity was detected at the direction of the incident field that is perpendicular to the long axis of the particle.Our preliminary results provided useful way for obtaining deeper insight to the SERS mechanism.
文摘首先采用共沉淀法及交互盐酸羟胺还原法制备Fe_2O_3@Au核壳结构纳米粒子,利用凝集素修饰纳米粒子(Lectin-Fe_2O_3@Au NP),然后通过动态光散射(DLS)/聚丙烯酰胺凝胶电泳/磁滞回曲线进行表征。利用MTT法测纳米粒子的细胞毒性,将不同浓度的Lectin-Fe_2O_3@Au与结直肠癌SW620细胞相互作用,普鲁士蓝进行染色,使用紫外可见光谱法(UV-Vis)和光学显微镜进行观察。结果表明凝集素修饰的纳米粒子在细胞培养基中能够稳定存在,当纳米粒子浓度为0.72 n M时,结直肠癌SW620细胞的存活率仍高于90%,其作用强度依次为蓖麻凝集素(RCA)-Fe_2O_3@Au>麦胚凝集素(WGA)-Fe_2O_3@Au>伴刀豆素(Con A)-Fe_2O_3@Au,经过普鲁士蓝染色的细胞可以观察到RCA-Fe_2O_3@Au纳米粒子的存在,表明凝集素RCA具有作为修饰纳米粒子与结直肠癌SW620细胞靶向识别的潜力。
文摘针形铁黄纳米粒子表面包覆无机物如Si、Co等氧化物形成复合纳米粒子,是改善金属磁性记录粉性能的重要方式.采用ICP,TEM,XPS方法研究复合纳米粒子的表面性质,结果表明包硅复合粒子的表面形成均匀、致密的SiO2薄膜,表面层与基体表面间的界面结构类似异质结,导致粒子的XPS谱图中 Fe 2p谱峰发生2.7eV的化学位移;而包钴复合粒子由于钴在铁黄表面的吸附发生在部分晶面上而无法形成均匀、致密的薄膜,XPS谱图主要发生因表面荷电而导致的物理位移.
文摘In this paper,chemical co-precipitation method was employed to synthesize Fe3O4 nanoparticles which can be well dispersed in water by using citric acid as a surfactant.Afterwards,by using Fe3O4 nanoparticles as seeds in a Triton X-100/hexanol/cyclohexane/water reverse microemulsion system,the core-shell structural Fe3O4@SiO2 nanocomposite particles were prepared via hydrolysis and condensation of tetraethyl orthosilicate(TEOS) under the catalysis of alkali.The effects of different stirring methods and the concentration of TEOS on the morphology of Fe3O4@SiO2 nanoparticles were investigated.The results show that the mechanical stirring can effectively control the morphology of composite nanoparticles to form a good dispersion and spherical morphology of core-shell nanoparticles.With the increase of TEOS concentration,the thickness of the SiO2 shell increases,and the morphology of the composite particles becomes more uniform.
