Fabrication And Application Of Highly Sensitive Optical Fiber Surface Plasmon Resonance Sensors

Focused on the fabrication and application of optical fiber surface plasmon resonance(SPR)sensors,we are devoted to optimizing the optical properties of SPR sensors by applying nanostructure with special morphology to film material and two-dimensional material to improve the sensitivity.Moreover,the sensors with good performance were used for immunoassays to set the base for future applications.The conclusions were drawn as follows.(1)Fabrication of local surface plasmon resonance(LSPR)sensors based on branched gold nanoparticles for immunoassays.In this part,gold nanomaterial with branched nanostructures were in situ synthesized on optical fiber.And the optical fiber LSPR sensors was fabricated and applied for immunoassays.Based on in situ reduction and silver-induced method,gold nanomaterials with branched nanostructure were fabricated on optical fiber.The temperatures and time of dopamine polymerization were optimized as well as the gold plating times.The LSPR sensor fabricated under optimal condition showed high sensitivity of 4091 nm/RIU with refractive index(RI)ranging from 1.33 to 1.38.For immunoassays,human Ig G(HIgG)was immobilized on the gold film to detect rabit-anti-human Ig G(RAHIgG).The fabricated biosensor reached the detection sensitivity of 0.086 nm/(?g/m L)during the concentration of RAHIgG 0-75 ?g/m L.(2)Modifications of optical fiber SPR sensor for sensitivity enhancement and immunoassays.Based on the built SPR optical sensor in our lab,we applied carboxyl-functionalized graphene oxide(cGO)to improve the sensitivity of the sensor based on its distinct photoelectric property.To facilitate the binding and amount of protein on the sensor surface,graphene oxide(GO)was first functionalized with carboxyl groups.In the experiments,modification methods and concentration of cGO were optimized,and the sensors modified under the optimal condition had a sensitivity increase up to 28.3% comparing with unmodified sensor.To test the detectability of the built sensor,RAHIgG was immobilized on the sensor surface and used for the detection of different concentrations of HIgG.As a result,the modified SPR sensor showed good detection sensitivity of 0.13 nm/(?g/m L)for the concentration of HIgG at 0-100 ?g/m L.At last,the as-prepared biosensor was tested in different solutions of antigen to confirm its specificity and selectivity to HIgG.