A study of paper-fluidic device using wax printing and photolithography

The emergence of paper based analytical devices (μPADs) since 2007 has had a major impact on the development of low cost, environmental friendly and simple microfluidic chips, serving in the field of medical diagnosis, food preserving and environmental monitoring. Although many fabrication techniques have evolved as a result of its broad application spectrum and ease of use, the technology has still barely scratched the surface of its potential in terms of its underlying fundamental principle i.e. fluid flow analysis. In this research we have compared two fabrication techniques of photolithography and wax printing with respect to fluid flow inside the porous media. The modified channel fabrication protocol is described. Hydrophilic and hydrophobic fluids are used for a flow comparison. Previous studies so far show channel width modification for attaining different flow velocities, whereas we have modified the channel by adding cylindrical resistance and attained variable velocity profile by keeping the same length and width of channel. Results show the flow follows the Lucas-washburn equation and variation in flow profile is attained by varying resistance configuration.