An assembly disposable degassing microfluidic device using a gas-permeable hydrophobic membrane and a reusable microsupport array

We introduce an assembly disposable degassing (ADD)-method as a simple and fast active degassing method. The ADD-method is achieved with a microstructured disposable superstrate and a reusable microsupport substrate, which can be assembled and disassembled simply by vacuum pressure. The reusable substrate can be equipped with functionalities to create an elaborately patterned energy field for active manipulation of substances in the microchannel. Degassing performance was evaluated for varying thicknesses of the polydimethylsiloxane (PDMS) membrane and heights of the microsupport array. Based on the ADD-method, an active bubble-trap structure was developed to prevent bubble injection into the microchannels. Deterministic lateral displacement and microvortex devices, as complex structured microfluidic devices that are easily suffered by bubble formation, were used to demonstrate the usefulness of the ADD-method. As a test vehicle of active functional microfluidic devices, an assembly-disposable degassing lateral magnetophoretic microseparator (CTC-addChip) was developed. For the CTC-addChip, a ferromagnetic wire array was inlaid on the reusable substrate to create a high-gradient magnetic field, which can transfer through the PDMS membrane and isolate circulating tumor cells with magnetic nanobeads in the microchannel without bubble interference.