Research On Immunoreaction-induced Scattering Effect In Optofluidic Laser

Optofluidic laser-the integration of microfluidics and laser technology-has been widely studied in drug screening,biochemical and medical sensing due to its excellent reconfigurability and unique signal amplification mechanism.Immunoassay is a biochemical detection method that uses immunoreaction to detect protein molecules in solution.Immunoassay based on the principle of light scattering is one of the most important analysis techniques.Immunoassays are generally performed in traditional biochemical analyzers.Due to the limitations of sensing principle,some difficult problems are exposed:(1)traditional biochemical analyzers are based on the principle of single-pass light scattering,which makes it difficult to achieve low concentration and high sensitivity detection;(2)traditional biochemical analyzers use cuvettes as the container of analyte,which often requires a large amount of samples and reagents and is not conducive to reduce the cost of biochemical test.Aiming at the shortcomings of traditional immunoassay technology,emerging optofluidic laser technology was combined with particle-enhanced immunoassay technology to study immune scattering characteristics by using the optofluidic laser based on Fabry-Perot cavity as a platform.The problems of low sensitivity and large consumption of reagents in traditional biochemical analyzers are solved.The main researches include:First,the selection of optofluidic laser gain materials,the structure of the resonant cavity and the scattering characteristics of the analytes in the cavity was discussed.Single-channel and dual-channel sensing modes based on Fabry-Perot cavity were proposed.The sensing characteristics of the optofluidic laser for immunoassay was simulated,including the effect of scattering wavelength,Q-factor of resonant cavity and gain on its performance.Secondly,a single-channel optofluidic laser based on Fabry-Perot cavity was established,and the laser threshold,stability and laser spectrum of the device were studied.With the device,the optofluidic laser scattering characteristics of polystyrene(PS)was studied.The results show that optofluidic laser output intensity decreases with the increase of PS microsphere concentration.Under the same concentration,larger PS microspheres cause greater scattering loss in the cavity,resulting in a decrease in laser output intensity.In addition,the laser scattering and cavity-free fluorescence scattering were compared,and the amplification mechanism of the optical resonant cavity on the scattering signal was discussed.Finally,based on the study of scattering characteristics of PS microspheres,the?₂-microglobulin(?₂-MG)antigen-antibody immune complex was used as the crosslinking agent between polystyrene microspheres to characterize particle-enhanced?₂-MG immune scattering with optofluidic laser.For the concentration sensing of?₂-MG,a dynamic range of three orders of magnitude and a limit of detection(LOD)of 0.16 ng/m L were achieved.There are low biomarker levels in body fluid for some diseases,especially in the early stages of their development.The realization of low concentration and high sensitivity detection is conducive to achieve early diagnosis of the diseases.In addition,the optofluidic laser has the advantages of low consumption of reagent by using microfluidic channel.This method is universal and can also be used for the detection of other antigen or antibody biomarkers.