Wang Tzyy-Jiann, Lin Wen-Shao, Liu Fu-Kuen
Institute of Electro-optical Engineering, National Taipei University of Technology, Taipei 106, Taiwan.
Biosens Bioelectron. 2007 Feb 15;22(7):1441-6. doi: 10.1016/j.bios.2006.06.014. Epub 2006 Jul 31.
We present a new integrated-optic surface plasmon resonance (SPR) biosensor based on electro-optical modulation. The SPR characteristics for the analyte concentration detection can be electro-optically modulated by applying the voltage on the electrodes of the biosensor fabricated on lithium niobate, which is an excellent electro-optic material. Two measurement methods, electro-optically modulated SPR spectral measurement and electro-optically modulated SPR intensity measurement, are demonstrated and their measurands are the SPR wavelength and the output optical intensity, respectively. Human serum albumin is coated on the gold film surface of the proposed biosensor to detect the concentration of beta-blocker, which is a remedy for heart disease. As the applied voltage increases such that the effective index of guided mode rises, the SPR wavelength shifts toward the long wavelength side and the output optical intensity at the wavelength of 632.8 nm diminishes. The linear regression slope of the relation between the measurand and the applied voltage is dependent on the analyte concentration and can be used to determine the concentration variation. Experimental results measured by the electro-optically modulated SPR methods are compared with those measured by the conventional spectral and intensity methods, and the effects of waveguide width on the biosensor performance are discussed.
我们展示了一种基于电光调制的新型集成光学表面等离子体共振（SPR）生物传感器。通过在基于铌酸锂（一种优异的电光材料）制造的生物传感器电极上施加电压，可以对用于分析物浓度检测的SPR特性进行电光调制。演示了两种测量方法，即电光调制SPR光谱测量和电光调制SPR强度测量，它们的测量量分别是SPR波长和输出光强度。在所提出的生物传感器的金膜表面涂覆人血清白蛋白，以检测β受体阻滞剂的浓度，β受体阻滞剂是一种心脏病治疗药物。随着施加电压增加，使得导模的有效折射率上升，SPR波长向长波长侧移动，并且在632.8nm波长处的输出光强度减小。测量量与施加电压之间关系的线性回归斜率取决于分析物浓度，可用于确定浓度变化。将通过电光调制SPR方法测量的实验结果与通过传统光谱和强度方法测量的结果进行比较，并讨论了波导宽度对生物传感器性能的影响。
