Study On Graphene Oxide Modified Long Period Fiber Grating Avian Influenza Virus Biosensor

As an important research field in fiber sensing,fiber grating sensing is being increasingly applied to label-free biosensing optical platforms since the 20th century.Not only does this platform have excellent performance comparable to classic optical platforms,but also has well-knit and microminiaturized optical fiber,and high-compatible optoelectronic devices(both sources and detectors),which can preserve the excellent performance of signal multiplexing and remote measurement.As a typical representative of fiber gratings,long-period fiber grating(LPFG)not only has the ability to resist external electromagnetic interference and harsh environmental conditions and implement real-time remote detection,but also has the advantage of being sensitive to changes in the external environment's refractive index,making it have great application potential and research value in the field of biosensing.Based on this,this paper will use LPFG and dispersion inflection point long-period fiber gratings(DTP-LPFG)as carriers,and combine graphene oxide(GO)and large-sized gold nanoshell(AuNS)materials to prepare highly sensitive avian influenza virus biosensors.The main research contents are as follows:(1)Biosensor based on cladding-etched Long Period Fiber Grating coated with Graphene Oxide.Firstly,the standard LPFG was etched with hydrofluoric acid(HF)to a cladding diameter of?114 ?m;then,the GO material was bonded to the surface of the cladding-etched LPFG(eLPFG)by hydrogen bonding;Next,Influenza virus monoclonal antibodies(AIV-MAbs)are covalently bonded to the sensor surface as a recognition unit;Then,GO-eLPFG biosensors are used to detect AIV biomolecules of different concentrations.Experimental results show that the detection limit(LOD)of the biosensor is?40 ng/mL,the detection sensitivity is?403.85 pm/?g·mL-1,and the detection range is 40 ng/mL?200 ?g/mL.The entire AIV immunoassay process follows the Langmuir biomolecule adsorption model.According to the model,the dissociation coefficient(Kd)and affinity coefficient(Ka)of the AIV biosensor are respectively?1.6×10-7 M and?6.25×106 M-1,respectively.Finally,a comprehensive evaluation of the reusability,specificity,and clinicality of the AIV biosensor was performed.The results show that the sensor has good specificity for AIV antigens and has potential for clinical application.(2)Biosensor based on Dispersion-Turning-Point Long Period Fiber Grating coated with Graphene Oxide.The GO material was modified onto DTP-LPFG using the surface modification method described above to prepare GO-DTP-LPFG AIV biosensor.By detecting high-purity AIV antigen solutions of different concentration levels,the immunosensor has a detection limit of?1.05 ng/mL,a detection saturation point of?25 ?g/mL,and a detection range of 1.05 ng/mL?25 ?g/mL.The dissociation coefficient(Kd)of the sensor is?1.6×10-7 M,and the affinity coefficient(Ka)is?1.88×108 M-1.In addition,a comprehensive evaluation of the reusability,specificity,and clinicality of the AIV biosensor was conducted.The experimental results show that the GO-DTP-LPFG AIV biosensor provides an excellent analysis platform for the field of biosensors,which holds the superiority of real-time monitoring,ultra-high sensitivity and multiple usability.(3)Biosensor based on Long Period Fiber Grating coated with Graphene Oxide Encapsulated Gold nanoshell.Firstly,the GO material was wrapped on the surface of AuNS by electrostatic bonding,forming a graphene oxide encapsulated gold nanoshell(EGO-AuNS)composite material.Then,EGO-AuNS was fixed on the surface of LPFG by a covalent bond adopted by a silane coupling agent(APTES);Then,AIV-MAbs was used as the recognition unit to fix the surface of the sensor by covalent bonding;Finally,the prepared EGO-AuNS-LPFG biosensor was used to achieve different concentration levels Detection of AIV biomolecules.The experimental results show that with the deposition of the EGO-AuNS composite on the surface of the LPFG,the refractive index sensitivity(?-66.60 nm/RIU)based on the resonance wavelength is increased by?6 times compared to the bare LPFG(?-11.00 nm/RIU).The detection limit of this AIV biosensor is?8 ng/mL,the detection sensitivity is?2946.25 pm/?g·mL-1,and the detection range is 8 ng/mL?50 ?g/mL.The dissociation coefficient of the sensor is?3.49×10-9 M,and the affinity coefficient is?2.87×108 M-1.The comprehensive evaluation of its reusability,specificity and clinicality shows that the sensor has a good specificity to AIV antigen and potential for clinical application.