Microfluidic patterning using a digital microfluidic system

There are some issues in printing technology, such as stencils having a brief life span and limitations in patterning; therefore, we propose microfluidic patterning using an electrowetting-on-dielectric (EWOD) and liquid-dielectrophoresis (L-DEP) system. Propylene carbonate liquid was generated, moved, separated, and positioned, and was patterned into various English alphabetic characters. Unlike traditional printing techniques, patterns become limited and fixed, so the shape of the desired pattern cannot be modified arbitrarily. Each single English alphabetic pattern can be formed with a volume of droplet of about 100 nl; the width of the pattern can be decreased to about 0.15 mm or less. Using an EWOD system, we have implemented an open-plate L-DEP system and a two-plate L-DEP system, for the patterning of all English alphabetic characters with the same volume of liquid at a fixed voltage.