Development Of A Miniaturized Flow Cytometer

Flow cytometers are widely used as a powerful analysis tool in biomedical research and clinical diagnostics. They can quantitatively analyze and sort individual micro/nano scale particles in a rapid and multi-parameter manner. However, the traditional flow cytometers with bulky volume and complex structure have limited their use for point-of-care applications. Developing miniaturized, integrated and portable flow cytometers based on microfluidic techniques is of great significance, and has become one of the major trends in the researches of flow cytometry.The dissertation is composed of three chapters:In Chapter one, an overview of various flow cytometers is given, including the principle of flow cytometry, the historical development and applications of flow cytometers. The techniques of fluid focusing, which are the core technology of fluid handling in the instruments, are also discussed in detail.In Chapter two, we developed a miniaturized flow cytometer. Base on a handheld laser induced fluorescence (LIF) detector, the instrument realized the simultaneous detection of forward scattering, side scattering and fluorescence. Utilizing 3D printing technology, each function module was integrated with a total volume of 26was in cm3. A 3D hydrodynamic focusing stream was automatically formed in a cross shaped structure. Two kinds of fluorescent microspheres were used as model samples to test the detectors' performance. We applied the miniaturized flow cytometer in cell apoptosis analysis.In Chapter three, we designed a new miniaturized flow cytometer with multicolor fluorescence detection. An orthogonal structure was adopted to realize as many as 4 channels of fluorescence detection on the same plane. Currently, we preliminarily completed the optimization of the cross shaped structure to obtain a more stable sheath flow and the location arrangement of focusing lens in the side scattering and fluorescence detection structures.