Mazhorova Anna, Markov Andrey, Ng Andy, Chinnappan Raja, Skorobogata Olga, Zourob Mohammed, Skorobogatiy Maksim
École Polytechnique de Montréal, Génie Physique, Québec, Canada.
Opt Express. 2012 Feb 27;20(5):5344-55. doi: 10.1364/OE.20.005344.
We propose for the first time an E. coli bacteria sensor based on the evanescent field of the fundamental mode of a suspended-core terahertz fiber. The sensor is capable of E. coli detection at concentrations in the range of 10(4)-10(9) cfu/ml. The polyethylene fiber features a 150 µm core suspended by three deeply sub-wavelength bridges in the center of a 5.1 mm-diameter cladding tube. The fiber core is biofunctionalized with T4 bacteriophages which bind and eventually destroy (lyse) their bacterial target. Using environmental SEM we demonstrate that E. coli is first captured by the phages on the fiber surface. After 25 minutes, most of the bacteria is infected by phages and then destroyed with ~1 μm-size fragments remaining bound to the fiber surface. The bacteria-binding and subsequent lysis unambiguously correlate with a strong increase of the fiber absorption. This signal allows the detection and quantification of bacteria concentration. Presented bacteria detection method is label-free and it does not rely on the presence of any bacterial "fingerprint" features in the THz spectrum.
我们首次提出了一种基于悬浮芯太赫兹光纤基模消逝场的大肠杆菌传感器。该传感器能够检测浓度在10⁴ - 10⁹ cfu/ml范围内的大肠杆菌。这种聚乙烯光纤具有一个150 µm的纤芯，由三根深度亚波长的桥支撑在直径5.1 mm的包层管中心。光纤纤芯用T4噬菌体进行生物功能化，T4噬菌体能够结合并最终破坏（裂解）其细菌靶标。通过环境扫描电子显微镜，我们证明大肠杆菌首先被光纤表面的噬菌体捕获。25分钟后，大多数细菌被噬菌体感染，然后被破坏，约1 µm大小的碎片仍附着在光纤表面。细菌结合及随后的裂解与光纤吸收的显著增加明确相关。该信号可用于检测和定量细菌浓度。所提出的细菌检测方法无需标记，且不依赖于太赫兹光谱中任何细菌“指纹”特征的存在。
