Wang Li, Wan Xiu-Mei, Gao Ran, Lu Dan-Feng, Qi Zhi-Mei
State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China.
School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100049, China.
Sensors (Basel). 2017 Jun 1;17(6):1255. doi: 10.3390/s17061255.
A wavelength-interrogated surface plasmon resonance (SPR) sensor based on a nanoporous gold (NPG) film has been fabricated for the sensitive detection of trace quantities of benzo[a]pyrene (BaP) in water. The large-area uniform NPG film was prepared by a two-step process that includes sputtering deposition of a 60-nm-thick AuAg alloy film on a glass substrate and chemical dealloying of the alloy film in nitric acid. For SPR sensor applications, the NPG film plays the dual roles of analyte enrichment and supporting surface plasmon waves, which leads to sensitivity enhancement. In this work, the as-prepared NPG film was first modified with 1-dodecanethiol molecules to make the film hydrophobic so as to improve BaP enrichment from water via hydrophobic interactions. The SPR sensor with the hydrophobic NPG film enables one to detect BaP at concentrations as low as 1 nmol·L. In response to this concentration of BaP the sensor produced a resonance-wavelength shift of Δλ = 2.22 nm. After the NPG film was functionalized with mouse monoclonal IgG1 that is the antibody against BaP, the sensor's sensitivity was further improved and the BaP detection limit decreased further down to 5 pmol·L (the corresponding Δλ = 1.77 nm). In contrast, the conventional SPR sensor with an antibody-functionalized dense gold film can give a response of merely Δλ = 0.9 nm for 100 pmol·L BaP.
一种基于纳米多孔金（NPG）薄膜的波长询问表面等离子体共振（SPR）传感器已被制备出来，用于灵敏检测水中痕量的苯并[a]芘（BaP）。大面积均匀的NPG薄膜通过两步法制备，该方法包括在玻璃基板上溅射沉积60纳米厚的AuAg合金薄膜以及在硝酸中对合金薄膜进行化学脱合金处理。对于SPR传感器应用，NPG薄膜起到分析物富集和支持表面等离子体波的双重作用，这导致了灵敏度的提高。在这项工作中，首先用1-十二烷硫醇分子对制备好的NPG薄膜进行修饰，使薄膜具有疏水性，从而通过疏水相互作用改善从水中富集BaP的效果。具有疏水NPG薄膜的SPR传感器能够检测低至1 nmol·L浓度的BaP。针对该浓度的BaP，传感器产生的共振波长偏移为Δλ = 2.22纳米。在用抗BaP的小鼠单克隆IgG1对NPG薄膜进行功能化后，传感器的灵敏度进一步提高，BaP检测限进一步降低至5 pmol·L（相应的Δλ = 1.77纳米）。相比之下，具有抗体功能化致密金膜的传统SPR传感器对于100 pmol·L的BaP仅能给出Δλ = 0.9纳米的响应。
