Universidade Estadual de Campinas, IFGW , Campinas, São Paulo 13083-859, Brazil.
Universidade Federal de Pernambuco, DQF , Recife, Pernambuco 50670-901, Brazil.
Langmuir. 2017 Mar 7;33(9):2257-2262. doi: 10.1021/acs.langmuir.6b04308. Epub 2017 Feb 20.
Aqueous colloidal silver nanoparticles have substantial potential in biological application as markers and antibacterial agents and in surface-enhanced Raman spectroscopy applications. A simple method of fabrication and encapsulation into an inert shell is of great importance today to make their use ubiquitous. Here we show that colloids of silver-core/silica-shell nanoparticles can be easily fabricated by a laser-ablation-assisted chemical reduction method and their sizes can be tuned in the range of 2.5 to 6.3 nm by simply choosing a proper water-ethanol proportion. The produced silver nanoparticles possess a porous amorphous silica shell that increases the inertness and stability of colloids, which decreases their toxicity compared with those without silica. The presence of a thin 2 to 3 nm silica shell was proved by EDX mapping. The small sizes of nanoparticles achieved by this method were analyzed using optical techniques, and they show typical photoluminescence in the UV-vis range that shifts toward higher energies with decreasing size.
水相胶体银纳米粒子作为标记物和抗菌剂，在表面增强拉曼光谱应用中具有很大的应用潜力。今天，一种简单的制造方法和封装到惰性壳中对于使其广泛应用非常重要。在这里，我们展示了可以通过激光烧蚀辅助化学还原法很容易地制造出银核/二氧化硅壳纳米粒子胶体，并且通过简单地选择适当的水-乙醇比例，可以将其尺寸调谐在 2.5 至 6.3nm 的范围内。所制备的银纳米粒子具有多孔无定形二氧化硅壳，增加了胶体的惰性和稳定性，与没有二氧化硅的胶体相比，其毒性降低。通过 EDX 映射证明了存在一个 2 至 3nm 的薄二氧化硅壳。通过该方法获得的小尺寸纳米粒子使用光学技术进行了分析，并且它们在 UV-vis 范围内显示出典型的光致发光，随着尺寸的减小，光致发光向高能位置移动。
