Applied Optics Group, Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD, UK.
Engineering Photonics, Cranfield University, Cranfield, Bedfordshire MK43 0AL, UK.
Biosens Bioelectron. 2016 Jan 15;75:222-31. doi: 10.1016/j.bios.2015.08.046. Epub 2015 Aug 22.
An optical fibre long period grating (LPG), modified with a coating of silica core gold shell (SiO2:Au) nanoparticles (NPs) deposited using the layer-by-layer method, was employed for the development of a biosensor. The SiO2:Au NPs were electrostatically assembled onto the LPG with the aid of a poly(allylamine hydrochloride) (PAH) polycation layer. The LPG sensor operates at the phase matching turning point to provide the highest sensitivity. The SiO2:Au NPs were modified with biotin, which was used as a ligand for streptavidin (SV) detection. The sensing mechanism is based on the measurement of the refractive index change induced by the binding of the SV to the biotin. The effect on sensitivity of increasing the surface area by virtue of the SiO2:Au nanoparticles' diameter and film thickness was studied. The lowest measured concentration of SV was 2.5nM, achieved using an LPG modified with a 3 layer (PAH/SiO2:Au) thin film composed of SiO2 NPs of 300nm diameter with a binding constant of k=1.7(pM)(-1), sensitivity of 6.9nm/ng/mm(2) and limit of detection of 19pg/mm(2).
一种采用层层法沉积的二氧化硅核金壳（SiO2:Au）纳米粒子（NPs）涂层修饰的光纤长周期光栅（LPG）被用于开发一种生物传感器。SiO2:Au NPs 通过聚（盐酸烯丙胺）（PAH）聚阳离子层静电组装到 LPG 上。LPG 传感器在相匹配转折点运行，以提供最高的灵敏度。SiO2:Au NPs 被修饰上生物素，用作链霉亲和素（SV）检测的配体。传感机制基于测量 SV 与生物素结合引起的折射率变化。通过 SiO2:Au 纳米粒子的直径和薄膜厚度增加表面积对灵敏度的影响进行了研究。使用由 300nm 直径的 SiO2 NPs 组成的 3 层（PAH/SiO2:Au）薄膜修饰的 LPG 实现了最低 SV 测量浓度 2.5nM，其结合常数为 k=1.7(pM)(-1)，灵敏度为 6.9nm/ng/mm(2)，检测限为 19pg/mm(2)。
