Dr. Sergio Freire
We present a new strategy for the fabrication of digital microfluidic (DMF) devices by research groups without access to well-equipped facilities. Compared to previously developed methods, it increases considerably device yield, and yet simplifies fabrication and enables flexible operation.
To this end, we use large (260 and 400 µm) interelectrode gaps to optimize substrate fabrication, breaking the established constraint that gap dimensions must be small (usually < 150 µm) for digital microfluidics. In fact, we show that interelectrode gaps are not limiting features for DMF performance, and may be quite large (> 1 mm). Smooth droplet actuation is ensured by films of perfluoroalkoxy (PFA), which do not require additional coatings; films can be instantly replaced, without the necessity of annealing. Finally, our tests indicate that DMF devices can operate with large distances between plates and droplet volumes (up to 2 mm and 60 µL, respectively), which implies in a flexibility in device operation not observed before.
Devices can move, split, and dispense from a reservoir, including droplets containing cells (the ciliated protozoa Tetrahymena thermophila). Altogether, we believe that the new strategy presented here will help expand the breadth of DMF applications.
digital microfluidics, large-gap electrodes, alternative devices
Thorne, Nathaniel; Lamberto, Melissa; Mazza, Audrey; and Freire, Sergio
"An Alternative Strategy for Fabrication of Robust and Flexible Digital Microfluidic Devices,"
Pacific Northwest Journal of Undergraduate Research and Creative Activities:
Vol. 2, Article 2.
Available at: http://commons.pacificu.edu/pnwestjurca/vol2/iss1/2