A Simple Method of Fabricating Weir-type Filters with Interdigital Aligned Full-polymer Microfluidic Channels for Blood Cell Fractionation

This paper describes a new method to fabricate large scale 3D weir-type filter for cell fractionation. The 3D structure is realized by a conformal bonding of two separate PDMS (poly-dimethyloxane) layers with in-situ microchannels which are formed by the conventional soft lithographic techniques. Moreover, the microfluidics channels on the two PDMS are set to cross to each other to increase weir numbers and flow throughput. The gap space of the weir filters depends on the thickness of the photoresist coated for the master formation, thereby it can be defined as required from submicron to hundreds micron scale. A white blood cells (WBCs) extraction experiments with the full polymer fabricated filters are conducted to validate the proposed method. The experimental results show that the weir-type filter array can fractionate the WBCs well from blood samples. Due to its intrinsic advantages of rapid process, high throughput and low cost, the proposed method is very promising for being integrated into micro total analysis system (muTAS)