静电组装金纳米粒子制备局域表面等离子体共振传感膜

采用聚电解质自组装技术制备局域表面等离子体共振(LSPR)传感膜的方法, 在玻璃基片上依次沉积聚电解质PDDA, PSS和PVTC, 并通过静电吸附构建胶体金纳米粒子自组装膜形成LSPR传感膜. 利用扫描电镜对LSPR传感膜表面形貌以及膜中金纳米粒子的粒径进行了表征, 同时通过紫外-可见消光光谱对其灵敏度和渗透深度等重要参数进行检测. 研究结果表明, 所制备的LSPR传感膜粒子分布均匀、单分散性好、稳定性高、重现性好; 消光峰位对样品溶液折射率的检测灵敏度为71 nm/RIU, 相应的峰强检测灵敏度为0.21 AU/RIU, 对表面吸附层的渗透深度约为16 nm.

Preparation of Localized Surface Plasmon Resonance Sensing Film with Gold Colloid by Electrostatic Assembly

This paper presents a new method to prepare localized surface plasmon resonance(LSPR) sensing film by self-assembly of polyelectrolyte. The optical signal arises from the dependence of the peak intensity and position of the localized surface plasmon spectrum of gold nanoparticles upon the refractive index of the surrounding medium. By using an electrostatic layer-by-layer assembly approach-PDDA/PSS/PVTC, 28 nm diameter colloidal gold nanoparticles are immobilized upon a glass substrate. The method yields a LSPR sensing film with good reproducibility and excellent stability. The spectroscopic response of the LSPR sensing film was investigated. The shift in the peak extinction wavelength and the change in the corresponding intensity of the LSPR band as a function of the refractive index of the solution are 71 nm/RIU and 0.21 a.u./RIU, respectively. The penetration depth of the electromagnetic field excited by LSPR upon the response of the sensing film is estimated to be about 16 nm.