3D (Three Dimensional) micro-fluidic structure for cell detection and preparation method thereof

The invention relates to a 3D (Three Dimensional) micro-fluidic structure for cell detection and a preparation method thereof. The entire structure is formed by connecting cover glass, a polydimethylsiloxane (PDMS) fluidic structure and a substrate in a sealing way, wherein a sheath fluid and sample fluid inflow channel (hole), a convergence cavity, a stepped structure and a convergence channel are carved on the PDMS fluidic structure, wherein the stepped structure and the convergence channel are used for realizing 3D focusing; in the convergence cavity, the designed channel shape can realize leftward and rightward focusing of fluid; and in the convergence channel, fluid flows through the stepped structure and is constrained in the vertical direction, so that the 3D focusing can be realized. Meanwhile, the invention provides a process method for preparing the micro-fluidic structure in a twice photoetching and one developing way. By adopting a simple structural scheme, 3D fluid focusing can be realized, and a good application effect and convenience for machining can be achieved; and the PDMS is taken as a structural material, so that low cost and high bio-compatibility are realized.