Research Of Optical Fiber Biosensor Based On Local Surface Plasmon Resonance

Traditional biosensors are mainly concentrated in the field of electrochemical sensing,and they are often costly.Optical fiber biosensing technology based on localized surface plasmon resonance(LSPR)effect has attracted wide attention of scientific researchers due to its anti-electromagnetic interference,strong sensitivity,remote monitoring,and low cost.In this paper,using ordinary single-mode fiber as the carrier,tapered fiber probes with different structures are designed,a variety of nanomaterials are synthesized,and used for the functionalization of the probes,and a novel LSPR high-sensitivity probe is constructed,using ascorbate oxidase.The specificity of Ascorbate Oxidase enables the detection of lowconcentration ascorbic acid solutions.The various sensing characteristics of the probe have been studied.details as follows:1.The fabrication of tapered optical fibers and the synthesis process of nanomaterials are studied.A tapered fiber with a diameter of 40 ?m was drawn using the Combiner Manufacturing System(CMS),which achieved rapid and repeatable drawing of a tapered fiber with a uniform taper area.And innovatively apply periodic multi-taper fibers to LSPR probes.Graphene oxide(GO)and gold nanoparticles(AuNPs)were synthesized by the modified Hummer method and Tukovich method,respectively.The GO,AuNPs and oxidizing nanoparticles(Zn O-NPs)were characterized by ultraviolet-visible spectrophotometer and high-resolution transmission electron microscope(HR-TEM).The synthesized GO has a two-dimensional flake structure,and the AuNPs are spherical particles with a diameter of about 10 nm,which have good dispersion and uniformity;2.The AuNPs/ZnO-NPs/AOx tapered fiber LSPR probe was studied.The molecular self-assembly technology is used to form a uniform monolayer distribution of thiol groups on the surface of the tapered fiber,and the uniformly distributed AuNPs are fixed to the surface of the tapered fiber through the strong covalent bond and interaction of gold and thiol.Afterwards,the surface of the optical fiber was functionalized with Zn O-NPs,and a blank control was set.The response of the probe to the concentration of ascorbic acid(AA)was compared,and the relationship between the concentration and the resonance wavelength was analyzed.The probe with Zn O-NPs has better sensing characteristics,and the probe has good reproducibility and high sensitivity;3.In order to further enhance the sensitivity of the probe,the AuNPs/GO/AOx multitaper fiber LSPR probe was studied.The multi-taper fiber has a smaller size,and the length of the entire tapered area is within a few microns.Through continuous dipping and quenching operations,rich GO was modified on the surface of the fiber fixed by AuNPs.It provides more attachment sites for the reaction of AA molecules and also improves the biocompatibility of the probe.The sensor probe has high sensitivity,high specificity,high reproducibility,linear measurement range of 0.01-1 m M,including the concentration of AA in the human central nervous system(100-500 uM).