Color inkjet-printing microfluidic paper chips by all-in-one multilayers

Y. Kim, H. Ko, J. Lee, H. Kim, C-H Jung, J-H Choi, O-S Kwon, K. Shin
Sogang University, KR

Keywords: inkjet printing, paper chip, electrowetting, CNT ink, patterned electrodes, microfluidic chips

Summary:

Only by printing way using an inkjet-printer, a paper-based microfluidic chip has been fabricated, including all of functional multilayer films coated with corresponding polymer inks, instead of color inks. A drop on the microfluidic paper chip is moved by voltage actively and in the programmed way such that it needs the patterned rail of electrodes coated with a dielectric film, a water resistant film and a top-coated film of either hydrophobic or a low frictional material to adjust the surface tension easily. By matching the viscosity, the CNT ink was formulated by using the ball-milling method to print the electrodes on the paper. For the subsequent dielectric, the water resistant and the top-cover films, each ink solution of SU-8, Hyflon and the silicon oil was employed and filled into a color cartridge, respectively. Therefore, all processes required for fabrication of a chip can be accomplished quickly, finely and precisely without complicated wet-lab processes, replacing expensive, complex, multi-step conventional optical lithography. This paper chip has many advantages largely, enabling especially the mass production for the low-cost medical diagnosis chips at the point of care, helping peoples in remote and isolated regions with limited resources, particularly in developing countries.