Fabrication of paper micro-devices with wax jetting

Paper microfluidic devices are a promising technology in developing analytical devices for point-of-care diagnosis in the developing world. This article describes a novel method of wax jetting with a PZT (piezoelectric ceramic transducer) actuator and glass nozzle for the fabrication of paper microfluidic devices. The hydrophobic fluid pattern was formed by the permeation of filter paper with wax droplets. Results showed that the size of the wax droplet, which was determined by the voltage of the driving signal and nozzle diameter, ranged from 150 μm to 380 μm, and the coefficient of variation of the droplet diameter was under 4.0%. The smallest width of the fluid channel was 600 μm frontside and 750 μm backside. The patterned filter paper was without any leakage, and multi-assay of glucose, protein, and pH on the paper microfluidic device, and laminar diffusion flow with blue and yellow dye were realized. The wax jetting system supplied a low-cost, simple, easy-to-use and fast fabrication method for paper microfluidic devices.