Tommaso F. Bersano-Begey, Yoko Kamotani and Shuichi Takayama
from: Lab-on-a-Chip Technology (Vol. 2): Biomolecular Separation and Analysis (Edited by: Keith E. Herold and Avraham Rasooly). Caister Academic Press, U.K. (2009)
This chapter describes protocols for fabrication and assembly of microfluidic chips designed for Braille-display-based fluid actuation. Emphasis is placed on critical fabrication details such as channel cross-sectional shape and dimensions, and membrane thickness. Commercial sources for the Braille display hardware and some simple software operation are also described. A detailed example of a protocol for a chip used for immunoassays using the Braille display for fluid actuation is also described. Braille Microfluidics is a microfluidic technology which uses arrays of small retractable pins on pre-existing Braille hardware as the actuation and control mechanism for elastomeric microfluidic chips. Braille actuation enables microfluidic pumping and valving without tubings and interconnects; the channels within the microfluidic chip are fabricated with a thin bottom membrane and are aligned over the Braille pins to interact with them. As the pins are raised or retracted they can perform all of the basic microfluidic operations such as valving, peristaltic pumping, and mixing.Among the advantages of this setup are ease of fabrication (single layer and no interconnections), portability (the entire system can be configured to occupy just the size of a hand) and high-programmability (all pins, and hence all the microfluidic valves they actuate, can be independently addressed and controlled automatically through a computer with a USB connection). However the same setup also introduces new challenges, such as an increased evaporation rate through its thin bottom membrane and a pulsatile flow which is not always desirable. A few solutions to these problems along with applications in which the Braille system is used are briefly discussed read more ...