Walter Schottky Institut, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany.
Nanotechnology. 2012 Mar 23;23(11):115607. doi: 10.1088/0957-4484/23/11/115607. Epub 2012 Mar 2.
We report the photo-induced nucleation and growth of silver nanoparticles in aqueous solution in the presence of DNA oligomers. An organic dye (Cy5) was used as a photosensitizer to initiate the nanoparticle growth upon illumination with 647 nm light. The formation of nanoparticles and growth kinetics were observed by extinction spectroscopy, dynamic light scattering, and transmission electron microscopy. Irradiation of the precursor solutions with light at the Cy5 absorption maximum triggered the instantaneous formation of spherical particles with a metallic core ~15 nm in diameter. Remarkably, the particles feature significantly larger effective hydrodynamic diameters (35 nm) in solution, indicative of a DNA ad-layer on the nanoparticle surface. Centrifugation experiments confirmed that DNA was inseparably associated with the nanoparticles and indicated that DNA oligomers adsorb onto the nanoparticle surface during growth, playing the role of a capping agent. The introduced method is a fast and facile way to prepare DNA-capped silver nanoparticles in a single growth step.
我们报告了在 DNA 寡聚物存在下，水溶液中银纳米颗粒的光诱导成核和生长。一种有机染料（Cy5）被用作光增敏剂，在 647nm 光照射下引发纳米颗粒生长。通过消光光谱、动态光散射和透射电子显微镜观察了纳米颗粒的形成和生长动力学。在 Cy5 吸收最大值的光照射下，前驱体溶液的辐照瞬间触发了具有约 15nm 直径的金属核的球形颗粒的形成。值得注意的是，颗粒在溶液中具有显著更大的有效水动力直径（35nm），表明纳米颗粒表面存在 DNA 加层。离心实验证实 DNA 与纳米颗粒不可分离地结合在一起，并表明 DNA 寡聚物在生长过程中吸附在纳米颗粒表面上，起到了封端剂的作用。所提出的方法是在单个生长步骤中快速简便地制备 DNA 封端的银纳米颗粒的方法。
