Photonic and Instrumentation Laboratory, Electrical Engeineering Program, Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro, Brazil.
Division of Chemical, Biological and Nuclear Defence, Biological Defence Laboratory, Brazilian Army Technological Center, Rio de Janeiro, RJ, Brazil.
Biosens Bioelectron. 2014 Apr 15;54:661-6. doi: 10.1016/j.bios.2013.11.030. Epub 2013 Nov 18.
This work presents a novel, fast response time, plastic optic fiber (POF) biosensor to detect Escherichia coli. It discloses the technique for the development, calibration and measurement of this robust and simple-to-construct POF biosensor. The probes in U-shaped format were manufactured with a specially developed device. The calibration process led to the evaluation of the sensitivity, accuracy and repeatability by using solutions of sucrose for obtaining refractive indices (RI) in the range 1.33-1.39 IR equivalent of water and bacteria, respectively. The POF probes were functionalized with antibody anti-E. coli serotype O55 and tested firstly with saline and then with bacterial concentrations of 10(4), 10(6), and 10(8) colony forming units/ml (CFU/ml). The optoelectronic setup consists of an 880 nm LED connected to the U-shaped probe driven by a sine waveform generated by the Simulink (from Matlab(®)). On the other side of the probe a photodetector generates a photocurrent which is amplified by a transconductance amplifier. The output voltage signal is read by the analog-to-digital (A/D) input of the microcontroller. In all tested concentrations, the results presented a tendency of a decrease in the output signal with time, due to the attachment of the bacteria to the POF probe and consequent increase in the RI close to the sensitive area of the fiber surface. It has been shown that the system is capable of providing positive response to the bacterial concentration in less than 10 min, demonstrating good possibilities to be commercially developed as a portable field sensor.
本工作提出了一种新颖的、快速响应时间的塑料光纤（POF）生物传感器，用于检测大肠杆菌。它揭示了开发、校准和测量这种坚固且易于构建的 POF 生物传感器的技术。U 形格式的探头是使用专门开发的设备制造的。校准过程通过使用蔗糖溶液来评估灵敏度、准确性和重复性，以获得折射率（RI）在 1.33-1.39 水等效范围内，分别为细菌。POF 探头用抗大肠杆菌 O55 血清型的抗体功能化，并首先用生理盐水进行测试，然后用浓度为 10(4)、10(6)和 10(8)菌落形成单位/ml（CFU/ml）的细菌进行测试。光电设置包括一个连接到 U 形探头的 880nm LED，由 Simulink（来自 Matlab(®)）生成的正弦波驱动。在探头的另一侧，光电探测器产生光电流，由跨导放大器放大。微控制器的模拟数字（A/D）输入读取输出电压信号。在所有测试浓度下，结果都呈现出随着时间的推移输出信号下降的趋势，这是由于细菌附着在 POF 探头上，导致靠近光纤表面敏感区域的 RI 增加。结果表明，该系统能够在不到 10 分钟的时间内对细菌浓度做出阳性响应，显示出作为便携式现场传感器进行商业开发的良好可能性。
