Rijal Kishan, Leung Angela, Shankar P Mohana, Mutharasan Raj
Department of Chemical Engineering, Drexel University, Philadelphia, PA 19104, USA.
Biosens Bioelectron. 2005 Dec 15;21(6):871-80. doi: 10.1016/j.bios.2005.02.006.
Optical fibers (core diameter 8 microm, cladding diameter 125 microm) was tapered to a waist diameter in the range of 8-12 microm, and then a monoclonal antibody to the pathogen, Escherichia coli O157:H7 was covalently bonded to the surface of the tapered region. Using 470 nm light, the taper was exposed to various concentrations (7 x 10(7), 7 x 10(5), 7 x 10(3), and 70 cells/mL) of the pathogen, and the sensor showed changes in transmitted light as the antigen attached to the antibody on the taper surface. The response was equal and opposite when the pathogen was released from the surface using a low pH buffer. The magnitude of the change was inversely proportional to the concentration of the pathogen. The sensor showed good sensitivity at as low a concentration as 70 cells/mL. The antibody-immobilized taper sensor was also exposed to a mixture of the pathogen and a non-pathogenic variant (JM101) at 0%, 50% and 70% by concentration. The sensor showed good selectivity to the pathogenic antigen. A first order attachment kinetic model is proposed to quantify the rate of attachment of pathogen to the sensor surface. The kinetic rate constant (k) of E. coli O157:H7 to the fiber was found to vary in the range of (2.5-6.1) x 10(-9) min(-1) (cells/mL)(-1).
将光纤（纤芯直径8微米，包层直径125微米）拉锥至腰部直径在8 - 12微米范围内，然后将针对病原体大肠杆菌O157:H7的单克隆抗体共价结合到拉锥区域的表面。使用470纳米的光，使拉锥暴露于不同浓度（7×10⁷、7×10⁵、7×10³和70个细胞/毫升）的病原体中，当抗原附着在拉锥表面的抗体上时，传感器显示出透射光的变化。当使用低pH缓冲液将病原体从表面释放时，响应是相等且相反的。变化的幅度与病原体的浓度成反比。该传感器在低至70个细胞/毫升的浓度下显示出良好的灵敏度。将固定有抗体的拉锥传感器也暴露于浓度分别为0%、50%和70%的病原体与非致病性变体（JM101）的混合物中。该传感器对致病性抗原显示出良好的选择性。提出了一个一级附着动力学模型来量化病原体附着到传感器表面的速率。发现大肠杆菌O157:H7与光纤的动力学速率常数（k）在（2.5 - 6.1）×10⁻⁹分钟⁻¹（细胞/毫升）⁻¹的范围内变化。
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