Study on the Preparation and Test of Hydrodynamic Focusing Microfluidic Chip Fabricated by Liquid Crystal Display Mask Photo-Curing Method

Microfluidic chips with the function of hydrodynamic focusing is widely used in the field of cell electroporation, droplet formation, drug screening and particle enrichment. Due to the small channel size of microfluidic chip, the existing processing methods have the defects of high fabrication cost or low dimensional consistency, the drawback is particularly prominent at small fabrication quantity. In this study, hydrodynamic focusing microfluidic chip was successfully fabricated by Liquid Crystal Display (LCD) mask photo-curing method with high efficiency and precision, the mechanism of curing parameters on the accuracy of microstructure was investigated, the hot pressing process was proposed to realize the bonding of cured photosensitive resin and glass substrate. By analyzing the focusing width of typical cross structure channel, a hydrodynamic focusing chip was designed. The effects of exposure time and single layer thickness on whole curing time was studied, the factors affecting the surface roughness were investigated, and the dimensional accuracy control method was proposed. The effect of bonding pressure on cured resin temperature was calculated and tested. The focusing width was verified by theoretical calculation and experiment. The mechanism for the inconsistency between the experimental focusing width and the theoretical focusing width was analyzed. The research proposed a solution of microfluidic design, fabrication, bonding and testing, which could provide a theoretical and methodological support for the efficient fabrication of microfluidic chips.