Microfluidic chip with microweir structure for continuous sample separating and collecting applications

We aim to establish a microfluidic chip device capable for continuous sample separation by integrating a simple and easy-fabrication microweir structure for crossflow filtration in the present study. The proposed microchip device is composed of two major components, including flow channels and microweir structure. Using the injection of the mixed samples with different sizes, the samples can be transported through the flow channel and then be separated by the microweir structure. The microweir structure with a different height can be generated by utilizing a standard lithography and overetching process, so that the gap can be used to be a selective tool to separate the smaller sample. In this study, a 10-μm gap was generated by established a microweir structure with 20 μm in height with a 20-minute etching process. Optimal sample separation efficiency in 82% can be obtained of the sample concentration in 103 μL−1 by utilizing the proposed design of the microweir structure to separate two groups of beads in different diameters. In conclusion, the proposed chip device can be regarded as an effective tool for clinical application.