Research And Experiment Of Reflective Fiber SPR Biosensor

Fiber surface plasmon resonance(SPR)technology is applied to the field of biological detection and environmental monitoring due to its mark-free,real-time detection and high sensitivity.The tilted fiber grating(TFBG)has a special angle between the grating and the core to generate the cladding mode,which produces the reverse transmission for stimulating the surface plasmon resonance,and the combination of TFBG and SPR technology is widely used in the field of biosensor.In this paper,a reflective TFBG-SPR biosensor is proposed,which is characterized by stable performance,corrosion resistance and mark-free.It also has the advantages of simple production process,quadratic coupling and field detection.Firstly,the development status of SPR fiber sensor,TFBG-SPR sensor and reflective fiber optic sensor is summarized.The theoretical basis of reflective SPR sensor is introduced.The basic principle and sensing characteristics of reflective TFBG-SPR sensor are analyzed,which provides a theoretical basis for the simulation and production.Secondly,the structure design of the reflective TFBG-SPR fiber optic sensor is carried out,and the appropriate production process is selected to complete the preparation of the reflective TFBG-SPR sensor.The magnesium chloride solution experiment is carried out on the sensor,and the sensitivity of the refractive index is 564.1nm/RIU,which is 245 times higher than that of the normal bare TFBG The modified sensor is applied to the bacterial concentration test.The experimental platform is built and the changes of the bacterial concentration are monitored in real time.All these jobs laid the foundation for the subsequent bacterial test and cell experiment.Finally,the reflective TFBG-SPR sensor was applied to two biomolecule experiments,namely DNA molecular experiment and protein molecular experiment.DNA molecules selected is methic ill in-resistant Staphylococcus aureus resistance gene,and the reflective TFBG-SPR DNA molecular probe is manufactured by overlaying fixed probe on the surface of the gold film,which can react with the complementary probe specifically.The reaction rate is determined by observing the resonance wavelength shift corresponding to the resonant peak of the sensor reflectance spectrum,and whether the reaction is carried out and the reaction speed is judged and analyzed.Reflected TFBG-SPR protein molecule is used to select the cysteamine hydrochloride as the intermediate material to immobilize the antigen on the surface of the gold film.The rabbit IgG molecule was immobilized and prepared into a protein molecular probe.The hybridization experiment is carried out.Rabbit IgG is specifically identified.The resonant wavelength of the reflection spectra is 9.5 nm in the hybridization experiment,illustrating that the experimental results are obvious and the feasibility of the two biomolecule probe experiments is verified.