We report use of U-shaped biconically tapered optical fibers (BTOF) as probes for label-free immunoassays. The tapered regions of the sensors were functionalized by immobilization of immunoglobulin-G (Ig-G) and tested for detection of anti-IgG at concentrations of 50 ng/mL to 50 µg/mL. Antibody-antigen reaction creates a biological nanolayer modifying the waveguide structure leading to a change in the sensor signal, which allows real-time monitoring. The kinetics of the antibody (mouse Ig-G)-antigen (rabbit anti-mouse IgG) reactions was studied. Hydrofluoric acid treatment makes the sensitive region thinner to enhance sensitivity, which we confirmed by experiments and simulations. The limit of detection for the sensor was estimated to be less than 50 ng/mL. Utilization of the rate of the sensor peak shift within the first few minutes of the antibody-antigen reaction is proposed as a rapid protein detection method.
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机译：我们报告使用U形双锥锥形光纤（BTOF）作为无标记免疫分析的探针。通过固定免疫球蛋白-G（Ig-G）功能化传感器的锥形区域，并测试其在50 ng / mL至50 µg / mL浓度下的抗IgG检测。抗体-抗原反应产生了生物纳米层，该生物纳米层修饰了波导结构，从而导致传感器信号发生变化，从而可以进行实时监控。研究了抗体（小鼠Ig-G）-抗原（兔抗小鼠IgG）反应的动力学。氢氟酸处理可使敏感区域变薄以增强灵敏度，我们通过实验和模拟证实了这一点。传感器的检出限估计小于50 ng / mL。提出了在抗体-抗原反应的最初几分钟内利用传感器峰移动的速率作为一种快速的蛋白质检测方法。
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