Using thermally printed transparency as photomasks to generate microfluidic structures in PDMS material

A simple fabrication method for poly(dimethylsiloxane) (PDMS) microfluidic device with minimal specialized equipment and facilities was described. Thermal color-printed transparency was used as photomask that utilizing patterns of different light opacity to generate multi-height microscale structures. The method offers rapid prototyping (3 h from concept to device) and high throughput production (multiple devices on 8 in. × 12 in. PCB board) capability while allows the customisation of feature depth by controlling etching time of PCB-based master. Leak-proof channel manifold with ∼200 μm intervals could be obtained, and multi-height structures provided added functions for the manipulation of liquid and particles in PDMS microfluidic devices. The liquid flow in the channels has the basic laminar flow characteristics and the multi-height structure can be used to trap particles such as biological cells.