Melt polymer drawn single and multi-capillary fibre-based electroosmotic pumps

Microfluidic devices have been employed in micro-analytical systems and microelectronics using inexpensive, customisable fluid-handling automation at the microliter scale. Here we utilise a well-established fibre drawing technique, which offers a range of materials and capillary conformations, that can be utilized within microfluidic devices to control fluid movement via electroosmotic processes to produce a simple electroosmotic pump (EOP). Single capillary EOPs were fabricated from drawn PU capillary fibres with internal diameters ranging from 73 to 200 µm and were shown to be capable of actively transporting a buffer solution using an external driving electric potential. A maximum flow rate of 0.8 ± 0.1 μL/min was achieved for a 73 ± 2 µm diameter PU capillary fibre at an applied potential of 750 V/cm. This flow rate was successfully increased up to 5.3 ± 0.3 μL/min by drawing a multi-capillary array consisting of 4, 5 and 7 capillaries.