改性石墨烯包覆光纤的马赫-曾德尔大肠杆菌传感器

针对日益严峻的食品安全问题,特别是食源性致病菌的快速检测,本文提出一种基于表面改性石墨烯粗锥型马赫-曾德尔干涉结构的光纤大肠杆菌传感器。首先,截取一根4 cm的实心光子晶体光纤,两端分别与两根单模光纤进行粗锥熔接,形成基于马赫-曾德尔干涉原理的传感结构;接着,制备一种表面改性石墨烯敏感材料,将它涂覆在实心光子晶体光纤的表面,使传感器对大肠杆菌溶液有较高的灵敏度;最后,将上述传感器置于水槽中,以此检测大肠杆菌溶液浓度。实验结果表明,在大肠杆菌溶液浓度为50~600 cfu/mL内,随着菌液的浓度增大,传感器的干涉光谱发生了明显的蓝移,灵敏度为3.43 pm/(cfu·mL^-1),菌液浓度与波长偏移的线性度为0.95649,检测限为67.18 cfu/mL,响应时间为15 s。该传感器成本低、体积小、响应时间快,适用于低浓度大肠杆菌浓度的快速检测。

Escherichia coli fiber sensor based on modified graphene coated fiber Mach-Zehnder interference

To solve increasingly serious food safety problems,especially the rapid detection of food-borne viruses,an E.coli sensor based on the surface-modified graphene enlarged-cone Mach-Zehnder interference structure was proposed in this study.First,a 4 cm solid photonic crystal fiber was intercepted and coarsely fused with two single-mode fibers to form an interference structure based on the Mach-Zehnder principle.Next,surface-modified graphene sensitive material was prepared.The modified graphene,coated on the surface of the solid photonic crystal fiber,allowed the sensor to have a higher sensitivity to E.coli solutions.Finally,the above sensor is placed in a water tank to detect the concentration of the E.coli.The experimental results show that the interference spectrum of the sensor has a significant blue shift with a sensitivity of 3.43 pm/(cfu·mL^-1)in the range of 50-600 cfu/mL of the E.coli solution.The linearity between the bacterial concentration and wavelength shift is 0.95649,detection limit is 67.18 cfu/ml,and response time is 15 s.The sensor has low cost,small volume,fast response time,and is suitable for the rapid detection of low concentration E.coli.