Nanoparticles Enhanced Fiber Optofluidic Laser And Its Sensing Application

Optofluidic laser sensor is a novel and highly sensitive sensing platform.The high Q-factor optical microcavity enhances the light-matter interaction,making the output laser intensity ultra-sensitive to its inner analyte.Nowadays,there are many research reports about optofluidic laser technology,and it gradually becomes one of the most important means of biochemical sensors.Recently,we demonstrated the concept of disposable fiber optofluidic laser,but is just limited to bulk solution applications.In this work,we propose the solid-surface of disposable fiber optofluidic laser,and be applied to highly sensitive horseradish peroxidase?HRP?detection.Nanoparticles own larger surface-to-volume ratio.In this work,we propose the nanoparticle-enhanced fiber optofluidic laser,in which the surface binding sites are increased for sensing molecules through nanoparticle-functionalized thin-walled hollow optical fibers?HOFs?,in order to amplify the sensing signal.Finally,we achieve a more sensitive fiber optofluidic laser sensor for horseradish peroxidase?HRP?detection.This paper focuses on a solid-surface of disposable fiber optofluidic laser and nanoparticles enhanced fiber optofluidic laser.The detailed work is as follows:?1?This paper firstly proposes a solid-surface of disposable fiber optofluidic laser sensor with a single-layer sensing molecules for horseradish peroxidase?HRP?detection,in which the inner surface of thin-walled HOFs is functionalized and biotinylated,and the streptavidin-biotin conjugation mechanism acts as a bridge to obtain the specific recognition of enzyme.This work includes resonate principle simulation,temporal variation test and lasing threshold test,and later achieves horseradish peroxidase?HRP?detection.This sensor owns high sensitivity,and could be applied for a single-use test.It can detect HRP in the range from 75 pM to 15 nM with a good linearity in semi-logarithmic scale,and the sensor has good sensing linearity and repeatability.?2?We propose and achieve an Au nanorods-enhanced fiber optofluidic laser sensor,and later achieve horseradish peroxidase?HRP?detection.By modifying Au nanorods onto the inner surface of thin-walled HOF through electrostatic absorption to increase the surface binding sites for sensing molecules,we achieve a more sensitive fiber optofluidic laser sensor for horseradish peroxidase?HRP?detection.A sensitivity enhancement of23.3%is achieved compared to the control group without nanoparticles according to the slope values,and experimental data indicates that it owns lower lasing threshold.However,we point out that higher concentration of AuNRs solution incubation may cause strong absorption,limiting the further improvement of sensitivity.?3?Considering the strong absorption effect under high concentration of Au nanorods solution incubation,we propose a SiO₂ nanospheres-enhanced fiber optofluidic laser sensor.Here,we select higher concentration of SiO₂ nanospheres solution which owns lower absorption coefficient,and then increase the surface binding sites by modifying SiO₂ nanospheres onto the inner surface of thin-walled HOF through biochemical cross-linking.Experiment data shows a higher sensitivity enhancement of57.4%compared to the control group without nanoparticles,and it also owns lower lasing threshold.