Design Of Fluorescence Detection And Analysis System For Microfluidic Droplet

Microfluidics is the technology that integrates multiple reactions into only a few square centimeters of micro-scale chip.It has been widely applied in biomedical due to its advantages such as less reagent consumption,high efficiency and less pollution.In order to monitor the reaction results on microfluidic chips,detection system is most inportant.The performance of the detector directly affects the detection limit,the detection speed,the application range of the whole microfluidic analysis system.Because fluorescence detection has the advantages of high selectivity and high sensitivity,it has become the most widely used method for microfluidic chip analysis.This thesis develops a fluorescence detection and analysis system based on microfluidic droplets.The software system and hardware system are designed by modularization.In order to ensure the stability of the system and avoid catastrophic errors,the design of anti-interference is taken into account.An Android App is designed for users to send instructions to the system and monitor the running state of the system in real time.The spatial filter is added to reduce the interference of stray light and improve the signal-to-noise ratio of the system.PMT is used as a detector to detect weak fluorescence.The distance between droplets will decrease with the increasing of the driving pressure of the discrete phase.The pressure of continuous phase is a main factor that affect droplet formation speed and droplet size.In order to ensure the system can detect the signal from one fluorescent droplet,it is necessary to adjust the driving pressure,so that there is a certain interval between the fluorescent droplets.When the fluorescent droplets pass through the fluorescence detection area,the peak signal can be detected by the system.The peak signals of 10 nM,30 nM,50 nM,70 nM and 90 nM respectively were analyzed.It can be found that the amplitudes of the peak signals linearly depend on the concentration of fluorescent drops.The peak distribution of different concentrations fluorescent droplets is very concentrated.Under the structure of the double T channel,the two concentrations of the fluorescent droplets are generated.By the detection of the optical detection system,the 10 nM and 90 nM fluorescent droplets can be distinguished by the peak value.Fluorescence detection has the advantages of high sensitivity,high selectivity and easily to combine with the chip.Fluorescence detection is the first choice to realize the portable detection system and promotes the development of genomics and molecular biology.