物理化学学报 >> 2019, Vol. 35 >> Issue (6): 630-636.doi: 10.3866/PKU.WHXB201806082

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基于金银合金薄膜的高灵敏度宽光谱表面等离子体共振成像传感器

梁爽1,2,高然1,张萌颖1,薛宁1,祁志美1,*()   

  1. 1 中国科学院电子学研究所,传感技术国家重点实验室,北京 100190
    2 中国科学院大学,北京 100190
  • 收稿日期:2018-04-27 录用日期:2018-06-05 发布日期:2018-10-31
  • 通讯作者: 祁志美 E-mail:zhimei-qi@mail.ie.ac.cn
  • 基金资助:
    国家重点基础研究发展规划项目(973)(2015CB352100);国家自然科学基金(61675203);中科院科研装备研制项目(YZ201508)

Gold-Silver Alloy Film Based Spectral Surface Plasmon Resonance Imaging Sensor with High Sensitivity

Shuang LIANG1,2,Ran GAO1,Mengying ZHANG1,Ning XUE1,Zhimei QI1,*()   

  1. 1 State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, P. R. China
    2 University of Chinese Academy of Sciences, Beijing 100049, P. R. China
  • Received:2018-04-27 Accepted:2018-06-05 Published:2018-10-31
  • Contact: Zhimei QI E-mail:zhimei-qi@mail.ie.ac.cn
  • Supported by:
    The project was supported by the National Key Basic Research Program of China (973)(2015CB352100);National Natural Science Foundation of China(61675203);Research Equipment Development Project of Chinese Academy of Sciences(YZ201508)

摘要:

报道了一种基于金银合金薄膜的宽光谱表面等离子体共振成像(SPRI)传感器,该传感器能够对吸附在薄膜局部或整个表面上的生化分子进行原位定量检测,而且与常规的金膜SPRI传感器相比,检测成本更低,检测灵敏度更高。利用质量比1 : 1的金银合金溅射靶在玻璃基板上淀积了厚约50 nm的均匀的金银合金薄膜。利用实验室自制的Krestchmann结构多功能平台在不同入射角下测试了金银合金薄膜被纯水覆盖后的SPR光谱和SPR彩色图像。基于色相算法计算获得了每个SPR彩像的二维色相分布及其平均色相,从而使得宽光谱SPRI传感器能够利用平均色相作为灵敏度参数进行定量检测。实验确定了平均色相对溶液折射率(RI)变化和分子吸附最为敏感的光谱区间是595–610 nm之间。在这个窄光谱范围内,平均色相与共振波长呈线性关系,其斜率为Δhue/ΔλR = 7.52 nm-1,这意味着基于色相的RI灵敏度是基于共振波长的RI灵敏度的7.52倍,这一结论已被实验证明。将SPRI传感器的起始共振波长设定在色相敏感光谱区间内之后,实验测得基于色相的RI灵敏度为S = 29879 RIU-1,比在相同条件下测得的金膜SPRI的灵敏度高8倍。利用时间分辨宽光谱SPRI方法实时监测了牛血清白蛋白(BSA)分子在金银合金薄膜表面的非特异性吸附,从实验测得的平均色相随时间的变化曲线可知BSA吸附达到平衡所需时间约15 min。研究结果表明,基于金银合金薄膜的SPRI传感器具有动态定量检测蛋白质分子吸附过程的功能。

关键词: 金银合金膜, 宽光谱SPR成像, 色相, 高灵敏度, 定量

Abstract:

This paper reports, for the first time, a gold-silver alloy film based broadband spectral surface plasmon resonance imaging (SPRI) sensor that enables in situ quantitative detection of chemical and biological molecules adsorbed on the partial or entire surface of the alloy film. The use of the gold-silver alloy film as the sensing layer makes the SPRI sensor lower in detection cost and higher in detection sensitivity as compared with the conventional sensor with a pure gold film. The gold-silver alloy films of ~50 nm thicknesses were deposited on glass substrates using a sputtering target made of gold (50%)-silver (50%, w, mass fraction) alloy. Both the SPR spectra and SPR color images for the gold-silver alloy films covered with pure water were measured at different incident angles using the laboratory-made Krestchmann-type multifunctional platform. The two-dimensional (2D) hue profile and the average hue for each SPR color image were obtained by calculation with the hue algorithm. Using the average hue as the sensitivity parameter, the spectral SPRI sensor enables quantitative detection. The spectral range in which the average hue is most sensitive to refractive index (RI) changes of bulk solution and to molecular adsorption was determined to be between 595 and 610 nm. In this narrow spectral range the average hue is linearly dependent on the resonant wavelength and its slope (representing the hue variation induced by per unit change in resonant wavelength) is Δhue/ΔλR = 7.52 nm-1, implying that the hue-based RI sensitivity is 7.52 times as high as the wavelength-based RI sensitivity. This implication was experimentally demonstrated in this work. After setting the initial resonant wavelength of the sensor in the hue-sensitive spectral range, the hue-based RI sensitivity of the SPRI sensor was measured to be S = 29879 RIU-1, which is 8 times higher than that obtained with the gold-film SPR chip under the same conditions (S = 3658 RIU-1 for the gold-film SPR chip). Nonspecific adsorption of bovine serum albumin (BSA) molecules on the gold-silver alloy film was monitored in real time by the time-resolved spectral SPRI method, and the temporal change in the average hue was obtained. The time required for BSA adsorption to reach equilibrium is determined to be about 15 min. This study illustrates that the gold-silver alloy film based SPRI sensor has the powerful capability of quantitative detection of sub-monomolecular adsorption of proteins.

Key words: Gold-silver alloy film, Broadband spectral SPR imaging, Hue, High sensitivity, Quantitative

MSC2000: 

  • O647