Department of Physical Chemistry/Applied Laser Sensing in Complex Biosystems (ALS ComBi), University of Potsdam, 14476 Potsdam, Germany.
School of Analytical Sciences Adlershof (SALSA), Humboldt-Universität zu Berlin, 10099 Berlin, Germany.
Sensors (Basel). 2018 Aug 28;18(9):2844. doi: 10.3390/s18092844.
We present the development of a label-free, highly sensitive fiber-optical biosensor for online detection and quantification of biomolecules. Here, the advantages of etched fiber Bragg gratings (eFBG) were used, since they induce a narrowband Bragg wavelength peak in the reflection operation mode. The gratings were fabricated point-by-point via a nonlinear absorption process of a highly focused femtosecond-pulsed laser, without the need of prior coating removal or specific fiber doping. The sensitivity of the Bragg wavelength peak to the surrounding refractive index (SRI), as needed for biochemical sensing, was realized by fiber cladding removal using hydrofluoric acid etching. For evaluation of biosensing capabilities, eFBG fibers were biofunctionalized with a single-stranded DNA aptamer specific for binding the C-reactive protein (CRP). Thus, the CRP-sensitive eFBG fiber-optical biosensor showed a very low limit of detection of 0.82 pg/L, with a dynamic range of CRP detection from approximately 0.8 pg/L to 1.2 µg/L. The biosensor showed a high specificity to CRP even in the presence of interfering substances. These results suggest that the proposed biosensor is capable for quantification of CRP from trace amounts of clinical samples. In addition, the adaption of this eFBG fiber-optical biosensor for detection of other relevant analytes can be easily realized.
我们提出了一种无标记的、高灵敏度的光纤生物传感器，用于在线检测和定量生物分子。在这里，我们利用了刻蚀光纤布拉格光栅（eFBG）的优势，因为它在反射操作模式下会产生一个窄带布拉格波长峰值。这些光栅是通过高度聚焦的飞秒脉冲激光的非线性吸收过程逐点制造的，而不需要预先去除涂层或进行特定的光纤掺杂。为了实现生化传感所需的布拉格波长峰值对周围折射率（SRI）的灵敏度，我们使用氢氟酸刻蚀去除光纤包层。为了评估生物传感性能，我们使用与 C-反应蛋白（CRP）结合的单链 DNA 适体对 eFBG 光纤进行了生物功能化。因此，CRP 敏感的 eFBG 光纤生物传感器的检测限非常低，为 0.82pg/L，CRP 检测的动态范围约为 0.8pg/L 至 1.2μg/L。即使存在干扰物质，该生物传感器对 CRP 也表现出很高的特异性。这些结果表明，所提出的生物传感器能够从痕量临床样本中定量 CRP。此外，这种 eFBG 光纤生物传感器很容易适应用于检测其他相关分析物。
