Research On The Sensing Characteristics Of Dopamine And Copper Ions Based On Optofluidic Laser

Optofluidic laser is a miniature dye laser formed by combining dye laser and microfluidic technology,using liquid dye molecules as the gain of the laser,and combining it with optical microcavity through microfluidic technology.The optofluidic laser not only has the basic characteristics of microfluidics which can operate light and fluid on a small scale,but also the laser signal produced by stimulated amplification has the advantages of narrow line width and good directionality.Through the amplification of the laser,the small changes of the dye in the cavity can be amplified to obtain higher sensitivity and lower detection limit,thus optofluidic laser has great advantages in biochemical sensing and detection.In this paper,we proposed an optofluidic laser sensor which based on a novel fluorescent probe.By combining the fluorescent probe with optofluidic laser technology,we obtained an optofluidic laser with low sample consumption,high sensitivity,and low detection limit.Moreover,the laser still containd the advantage of the diversity of fluorescent probes,easy synthesis and detecting specific analytes according to actual needs.The specific research contents are as follows:(1)Research on Fabry-Perot cavity optofluidic laser based on Rhodamine 6G and its application of dopamine sensing.In the experiment,we used a 532 nm pulsed laser at 10 Hz and 10 ns as the pump source and a Fabry-Perot cavity formed by coated mirrors with different reflectance as the optical resonator of the system to provide optical feedback amplification.And rhodamine 6G was used as the gain medium to build an optofluidic laser sensing system.By studying the correspondence between different concentrations of rhodamine 6G and the laser signal,the lowest response concentration of the system to rhodamine 6G is 10 ?M.Also,with the increase of rhodamine 6G concentration,the threshold of the optofluidic laser signal gradually decreases,while the slope efficiency of the optofluidic laser signal gradually increases.Thus,based on the research of this optofluidic laser system,we realized an optofluidic laser dopamine sensor.Dopamine can cause the ring formation in the rhodamine 6G screw,which reduces the fluorescent dye and weakens the fluorescence signal in the cavity.Under the amplification of the resonant cavity,the laser signal intensity will gradually decrease while the threshold gradually increases.Here,we demonstrated the relationship between different concentrations of dopamine and the optofluidic laser signal,and obtained the linear range of dopamine sensing detection which was 0-2 m M and the detection limit which was about 0.78 ?M.(2)Research on the detection of copper ion specific sensor based on R6G-HS optofluidic laser.Based on the conversion mechanism of R6G-HS probe from spirolactam(no fluorescence)to ring-opening amide(strong fluorescence),the chelation reaction between the R6G-HS probe and copper ion will produce strong fluorescent products.And after the pump light excitation and the stimulated amplification of the resonant cavity,the threshold of the laser signal will reduced and the efficiency of the laser signal increase.By studying the correspondence between different concentrations of copper ions and optofluidic laser output characteristics,we achieved the detection limit of copper ions based on R6G-HS probe optofluidic laser sensing system is 300 ?M and the detection linear range is 300-700 ?M.The interference ion detection results suggested that the sensor has excellent specificity.