Shahid Beheshti University, Evin, Tehran, Iran.
J Photochem Photobiol B. 2010 Dec 2;101(3):313-20. doi: 10.1016/j.jphotobiol.2010.07.017. Epub 2010 Aug 10.
A single-mode tapered fiber optic biosensor was utilized for real-time monitoring of the Escherichia coli (E. coli K-12) growth in an aqueous medium. The applied fiber tapers were fabricated using heat-pulling method with waist diameter and length of 6-7μm and 3mm, respectively. The bacteria were immobilized on the tapered surface using Poly-l-Lysine. By providing the proper condition, bacterial population growth on the tapered surface increases the average surface density of the cells and consequently the refractive index (RI) of the tapered region would increase. The adsorption of the cells on the tapered fiber leads to changes in the optical characteristics of the taper. This affects the evanescent field leading to changes in optical throughput. The bacterial growth rate was monitored at room temperature by transmission of a 1558.17nm distributed feedback (DFB) laser through the tapered fiber. At the same condition, after determining the growth rate of E. coli by means of colony counting method, we compared the results with that obtained from the fiber sensor measurements. This novel sensing method, promises new application such as rapid analysis of the presence of bacteria.
一种单模锥形光纤生物传感器被用于实时监测水溶液中大肠杆菌（E. coli K-12）的生长。所应用的锥形光纤是使用热拉伸法制造的，其腰部直径和长度分别为 6-7μm 和 3mm。细菌通过聚-L-赖氨酸固定在锥形表面上。在适当的条件下，锥形表面上的细菌种群生长会增加细胞的平均表面密度，从而导致锥形区域的折射率（RI）增加。细胞在锥形光纤上的吸附会导致光纤的光学特性发生变化。这会影响消逝场，导致光透过率发生变化。通过传输 1558.17nm 的分布式反馈（DFB）激光穿过锥形光纤，在室温下监测细菌的生长速率。在相同条件下，通过平板计数法确定大肠杆菌的生长速率后，我们将结果与光纤传感器测量的结果进行比较。这种新颖的传感方法有望应用于快速分析细菌的存在。
