Fabrication of microfluidic chips by sandwiching patterned plastic sheet by microscope slides

Microfluidic channel in a chip is the basic element of a lab on a chip (LoC) which is potential for automated cheap, fast, and sensitive biomedical, environmental, and food safety test. In this paper, the fabrication of simple microfluidic chips without using any cleanroom facility were reported. The chip was constructed by sandwiching a patterned stationery plastic sheet by two microscope slides. The pattern that defines the channel was designed using a CAD (computer aided design) program and cut using an off-the-shelf sticker cutter machine. The stack was thermally bonded in a kitchen oven above the glass temperature of the plastic sheet. We show successfully fabricated chips with a cross-shaped microfluidic channel with length of 5.45 cm for the long arm and 1.7 cm for the short arm, with channel width reaches 227.05 μm. The channel thickness can be controlled by the bonding parameter, e.g. the bonding time. We produced channels that go down to 81.3 μm thickness with 20 minutes of bonding at 110 °C. The observation of the fabricated channels was performed visually under a microscope. The functionality of the chips were characterized using a fountain pen ink and vegetable oil. We demonstrated an electro-osmotic flow of the fluids through the channel under several high DC voltage excitations.