Research On CD4+T Lymphocyte Automatic Counting And Detection System Based On Microfluidic Chip

In recent years, the Acquired Immune Deficiency Syndrome (AIDS) patients become more and more, which is not only a major public health problem, but also a major social problem. Human Immunodeficiency Virus (HIV) is the pathogen of AIDS and has great impact on human immune system. In clinical AIDS/HIV diagnosis, the absolute number of CD4+T lymphocyte can be used to predict the damage degree of immune system. Hospitals or scientific research centers commonly utilize flow cytometer to count CD4 cells, but the flow cytometer is so expensive and not suitable for the poor in remote areas that it is not conducive to the periodic treatment of AIDS. This paper aims to design a convenient, low cost and high sensitivity detection system based on microfluidic chip for automatically counting and detecting CD4+T lymphocyte.In this paper, we use magnetic beads to capture CD4+T lymphocytes and fluorescence detection method to count its number. Firstly, the magnetic beads labeled by CD4 antibody capture CD4+T lymphocytes in blood sample. Then, the captured CD4+T lymphocytes are fluorescently labeled.Finally, we can figure out the number of CD4+T lymphocytes by detecting the fluorescence intensity. In order to optimize the design of microfluidic chips and increase the mixing degree of magnetic beads and blood sample, we do some simulations of the traces of magnetic beads in different flow styles by ANSYS Fluent. Based on the simulation results, the repeated impingement mixing method is presented, which can significantly improve the efficiency of mixing beads with the test sample or reagent on the one hand, and can realize automatically detection of CD4+T lymphocytes on the other hand. This centrifugal microfluidic chip and supporting mechanical equipment are designed. The hardware and software system is designed based on STM32F407 microcontroller. Through the relevant testing and certification, we get the optimum operating parameters of the equipment for optimum mixing efficiency. Besides, we get the optimal mode of fluorescence detection. The different field tests with different volumes of sample verify the feasibility of the proposed automatic CD4+lymphocytes capture and detection system.