The Study Of Fiber-optic Interferometric Neurotransmitter Biosensor Functionalized With Mesoporous Microspheres

With increasing demand of timely diagnosis and detection of various diseases in modern society,biosensors have become the hotspot both in academia and industry because of their outstanding advantages and characteristics.In the field of biosensing,a variety of techniques are deeply integrated,particular to micro-processing technology,nanotechnology and information technology which are flourished,making the field of biosensors flourishing and shining.Among the best representatives,fiber-optic devices are often found excellent in the field of biosensing due to their simple structure,high sensing performance and other eminent properties.Through various structure optimizing and application integrating,as well as the combination of functional nanomaterials,fiber biosensing technology has made many influential applications.Involved in interdisciplinarity,and related to human life and health for the future,the study of optical fiber biosensor is promising,both for academic commity and industry.Micro-fiber,because of its unique large evanescent field characteristics,simple and flexible structure,provides a good research platform for fiber biosensing technology.As an important part of micro-fiber biosensor,fiber-optical interferometric biosensor posesses advantages of optical fiber biosensing technology,such as label-free,high sensitivity,specificity,simple and short response time.In this paper,the silica mesoporous materials have been incorporated with the fiber optic interometer.Target neurotransmitter molecules have been analyzed using the size selectivity of mesoporous materials,mainly includes:1.Silver core silica based mesoporous materials functionalized fiber-optic interferometric sensor for low concentraion serotonin(5-HT)detection: Herein,we modified the micro-fiber by using silver nanospheres coated with silica material.Attributing to the size filtration function of mesoporous,the 5-HT molecules gathered on fiber surface,enlarging the slight refractive index(RI)change caused by low concentration fluctuation of 5-HT.The microfiber translated the RI change into the wavelength shift in the interferometric fringe.Compared with the traditional methods,the sensitivity of this approach is obviously enhanced,and the detection limit achieved to 84 fM with response time apparently reduced.2.Detection of low concentraion ?-aminobutyric acid(GABA)by fiber-optic interferometric sensor functionalized with microspheres with Fe3O4 core and silica shell: As a kind of magnetic nanoparticles,Fe3O4 particles with biocompatibility are prepared as core of the SiO2 mesoporous microspheres,showing good stability,and adsorption/release capacity.In this work,the biosensor composed of a fiber-optic interferometer with diameter of microscale and mesoporous molecular sieves,was employed to detect low concentration GABA molecules.The size selectivity effect of the mesoporous molecular seives makes it possible to filtrate and gather the GABA molecules on fiber surface,monitoring the slight RI variations induced by low concentration GABA molecules to significant wavelength shift in the interferometric fringe.Compared with the traditional methods,such as electrochemical and fluorescence detection,the optical fiber biosensor based on wavelength calibration presents a detection limit of 351 f M with relatively good selectivity,which may provide a good foundation for further real serum samples detection.