Preliminary Study On Interferometric Microflow Sensor Based On Microstructured Optical Fiber

Microstructured optical fibers are widely used in optofluidic devices because of the integration of microfluidics paths and optical paths in the same optical fiber.Microfluidic optics is a new interdiscipline and technology.The optical or optoelectronic characteristics of the system are adjusted by manipulating the fluid at the microscopic scale and the optical phenomena in the microfluidic system are studied.In this thesis,a hollow twin-core microstructure fiber is presented,which has a microfluidic channel,a suspension core suspended in the hole and another core embedded in the cladding.An interferometric microfluidic sensor was prepared by using the hollow microstructured fiber,combining the advantages of streptavidin-biotin signal system in biological detection.The good application of hollow twin-core microstructured fiber inter ferometric microfluidic sensor in biological detection was verified in the experiment.In this thesis,the sensing principle of hollow twin-core microstructured fiber is investigated and the principle of combination of avidin and biotin signal amplification system is expatiated.Specifically,this thesis is divided into the following three parts:?1?On the basis of studying the preparation principle and method of microstructure fiber optic sensor,a hollow twin-core fiber interferometric microfluidic sensor was prepared according to the existing experimental conditions.The refractive index sensing theory of hollow twin-core fiber interferometric microfluidic sensor is analyzed and taken as a detector.By measuring the variation of NaCl solution's refractive index,it is known that the refraction index sensitivity of this sensor is 2577 nm/RIU.?2?On the basis of understanding the basic characteristics of streptavidin and biotin,as well as the binding principle and application method of various streptavidin-biotin systems.The advantages of the amplification system are analyzed.In the end,one of the combination of streptavidin and biotin was selected and combined with the microstructured fiber optic sensor.?3?The shining point of this thesis is the application of twin-core microstructure fiber optic interferometric microfluidic sensor to dynamically detect biotin concentration online.These include the binding of streptavidin on the surface of the hollow fiber suspension core,the capture of biotin by streptavidin,and the online detection of biotin concentration.Experiments have shown that the sensor can detect biotin molecules with a concentration range of 0.01-0.1 mg/mL without labeling,and the detection sensitivity of net biotin is 16.9nm/?mg/mL?with a minimum detection concentration of 3x10^-3 mg/mL.In addition,biotin can bind to almost all known biomacromolecules,such as proteins,nucleic acids,polysaccharides and lipids.Because each molecule of streptavidin can bind to four molecules of biotin,this property can be used to construct a multilevel signal amplification system.Therefore,the detection device can be applied to the quantitative and qualitative online detection of antigens,antibodies,cells,molds and other biological samples.