Fabrication of paper based microfluidic devices

This paper describes an inexpensive method of fabricating paper based microfluidic devices, a new point of care technology. The method uses a solid ink printer, chromatography paper and a heating source. The printer deposits wax onto the surface of the paper which is then melted to allow the wax to penetrate the depth of the paper. This results in hydrophobic barriers capable of guiding fluid movement through the paper. The paper provides a detailed study of process parameters critical to this fabrication process. It discusses the selection of the optimum line width, melting temperature and melting time required to generate impermeable hydrophobic barriers. It was found that line widths play a predominant role in the development of effective wax barriers, more so than other fabrication parameters. A comparison between the melting effectiveness of a hot plate and an oven is also given. To test barrier effectiveness, square chambers were printed and flooded with coloured dye. It was found that barriers narrower then 300μm do not form impermeable hydrophobic barriers.