Study Of The Fluid System Design Of The Diffraction Imaging Flow Cytometer

Flow cytometer, which is a new type of quantitative analysis and sortinginstrument for cells, could achieve the multi-parameter detection of functionallevel rapidly. However, it couldn’t achieve a good performance on the detectionof three-dimensional morphological information. Diffraction imaging flowcytometer, which is developed by our group based on the imaging principle torecord the diffraction images, could do well on the detection of morphologicalinformation. The experimental results show that the diffraction images coulddistinguish the B kind lymphocytes and T kind lymphocytes, and that abilitybrings significant value to cell morphological research. However, with the limitsof the camera shutter speed, it’s urgent to develop a kind of fluid system withlow flow speed to meet the requirements of shooting. In our work, the fluidsystem is studied intensively from the design of flow chamber and fluid-drivensystem and PID control of pressure.1) Flow chamber as a core component of flow cytometer, has a greatinfluence on the realization of the function of the instrument. The design of flowchamber, fluid motion analysis and the determination of the best detection zonelocation are carried out according to the characteristics of single fluid celldetection. And the structure of the fluid chamber is improved on the basis ofsimulations and experiments.2) Flow-driven systems are the key parts in the fluid flow system, and theywill affect the stability of core flow in the fluid chamber directly. Various kindsof flow-driven methods which are in gravity, syringe pump and pressure formshave been designed and tested. After lots of experiments, we pick up the solutionwith the sheath fluid driven by pressure and the core fluid driven by syringepump finally, based on comprehensive consideration of the stability of theshape of the core flow, compressed diameter, flow rate, and other factors.3) We design the digital PID closed-loop negative feedback system based onsingle chip microcomputer, pump and pressure sensor, and implement the PIDparameter adjusting. The experimental results show that in the fluid flow system,the core flow compression diameter in detection region is less than30μm, the core flow has a good stability and the flow rate of the core flow is under5mm/s,those parameters meet the requirements of the diffraction imaging flowcytometer.