单金纳米棒的光散射分析化学:径向比与分析灵敏度的关系

Light scattering analysis of single gold nanorod: the correlation between aspect ratio and analytical sensitivity

单纳米颗粒作为信号感应单元在化学与生物传感应用中已引起广泛关注.本文通过暗场显微成像(iDFM)研究了不同径向比金纳米棒的光散射性质.将iDFM与扫描电子显微镜(SEM)结合表征种子生长法制备的金纳米棒,结果发现,因局域表面等离子体共振而展示出的红色散射光随单个金纳米棒的径向比增大逐渐红移,且金纳米棒对其周围介质折光率(RI)变化的敏感程度随径向比增大而增大.这一结果对设计高灵敏的生物纳米传感器、提高分析检测的灵敏度具有很好的指导意义.

In this paper, aspect ratio-dependent localized surface plasmon resonance（LSPR） scattering of gold nanorods was investigated through dark-field microscopic imaging（iDFM） at single nanoparticles level. Seedmediated growth method was used to make gold nanorods with different aspect ratios. By combining iDFM with scanning electron microscope（SEM）, we found that single gold nanorods（AuNRs） scattered red light, and the scattering spectra of single AuNRs shifted towards to longer wavelength as the aspect ratio increased. In addition, the refractive index（RI） sensitivities of single AuNRs with different aspect ratios were proven to be different, and the RI sensitivities got higher with increasing aspect ratio. These results are of implication for further designing highly sensitive nanobiosensors and improving the detection sensitivity.