Yin Hong Jun, Chen Zhao Yang, Zhao Yong Mei, Lv Ming Yang, Shi Chun An, Wu Zheng Long, Zhang Xin, Liu Luo, Wang Ming Li, Xu Hai Jun
Beijing Key Laboratory of Bioprocess, Beijing University of Chemical Technology, Beijing, 100029, China.
Engineering Research Center for Semiconductor Integrated Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China.
Sci Rep. 2015 Sep 28;5:14502. doi: 10.1038/srep14502.
Surface enhanced Raman scattering (SERS) substrate based on fabricated Ag@Au core-shell dendrite was achieved. Ag dendrites were grown on Si wafer by the hydrothermal corrosion method and Au nanofilm on the surface of Ag dendritic nanostructure was then fabricated by chemical reduction. With the help of sodium borohydride in water, Au surface absorbates such as thiophene, adenine, rhodamine, small anions (Br(-) and I(-)), and a polymer (PVP, poly(N-vinylpyrrolidone)) can be completely and rapidly removed. After four repeatable experiments, the substrate SERS function did not decrease at all, indicating that the Ag@Au dendrite should be of great significance to SERS application because it can save much resource. Six-month-duration stability tests showed that the Ag@Au core-shell dendrite substrate is much more stable than the Ag dendrite substrates. We have also experimented on fast detection of Cd(2+) at 10(-8) M concentration by decorating single-stranded DNA containing adenine and guanine bases on the surface of this Ag@Au dendrite. Finite-difference time-domain simulations were carried out to investigate the influence of Au nanolayer on Ag dendrites, which showed that the local electric fields and enhancement factor are hardly affected when a 4 nm Au nanolayer is coated on Ag dendrite surface.
制备了基于Ag@Au核壳树枝状结构的表面增强拉曼散射（SERS）基底。通过水热腐蚀法在硅片上生长银树枝状结构，然后通过化学还原法在银树枝状纳米结构表面制备金纳米膜。在硼氢化钠的作用下，金表面的吸附物如噻吩、腺嘌呤、罗丹明、小阴离子（Br(-)和I(-)）以及聚合物（PVP，聚（N-乙烯基吡咯烷酮））能够被完全快速去除。经过四次可重复实验后，基底的SERS功能完全没有下降，这表明Ag@Au树枝状结构对SERS应用具有重要意义，因为它可以节省大量资源。为期六个月的稳定性测试表明，Ag@Au核壳树枝状结构基底比银树枝状结构基底更加稳定。我们还通过在这种Ag@Au树枝状结构表面修饰含有腺嘌呤和鸟嘌呤碱基的单链DNA，对10(-8) M浓度的Cd(2+)进行了快速检测实验。进行了时域有限差分模拟以研究金纳米层对银树枝状结构的影响，结果表明当在银树枝状结构表面包覆4 nm金纳米层时，局部电场和增强因子几乎不受影响。
