Oscillations in light-triggered logic microfluidic circuit
Name
542_2013_1899_ReferencePDF.pdf
Size
516.57 KB
Format
Adobe PDF
Checksum (MD5)
a71b59ae2163067cd849e67494f7ca56
Author(s)
Cartas Ayala, Marco Aurelio
Gilson, Laura M.
Shen, Chong
Karnik, Rohit
Date Issued
August 2013
Journal
Microsystem Technologies
Publisher
Springer Berlin Heidelberg
Citation
Cartas-Ayala, Marco A., Laura Gilson, Chong Shen, and Rohit Karnik. "Oscillations in light-triggered logic microfluidic circuit." Microsystem Technologies 20:3 (March 2014), pp. 437-444.
Version
Author's final manuscript
Abstract
Control of droplets in microfluidic environments has numerous applications ranging from analysis and sample preparation for biomaterials synthesis (Mann and Ozin Nature 382:313–318, 1996) and medical diagnostics (Pipper et al. Nat Med 13:1259–1263, 2007) to photonics (Schmidt and Hawkins Nat Photonics 5:598–604, 2011). Here we study the oscillations present in a microfluidic circuit capable of sorting curable droplets on demand by triggering the circuit with UV-light. Prior to this paper we showed that a simple circuit can self-sort particles and produce a binary output, sorted or rejected stream of particles, based on the hydrodynamic resistance induced by the particles as they flow through the microfluidic channels. We showed that the cross-linking of droplets can modulate the resistance, and demonstrated particle switching by sorting of otherwise identical droplets of uncured and cured photocurable solution immersed in mineral oil solution. Before arriving at the sorting circuit, droplets made of a photocurable solution were illuminated by a UV-light from a mercury lamp, curing them. By tuning the outlet pressures, the switching threshold could be tuned so that uncured droplets were rejected while cured droplets were switched (Raafat et al. μTAS Proc 1826–1828, 2010; Cartas-Ayala et al. Small 9:375–381, 2013). Here we use this system to study the oscillations in this circuit due to particle–particle interactions in the circuit. The circuit oscillation can be used as a counter with a light ON/OFF switch. The circuit behavior agrees well with theoretical predictions of droplet oscillations. Furthermore, the circuit oscillations can be switched on or off by UV-light illumination. This experiment demonstrates switching of particles based on deformability, illustrates the switching of particles by using light, and the possibility of creating new managing schemes for droplets by combining light control with droplet generation-rate control.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
Terms of Use
Creative Commons Attribution-Noncommercial-Share Alike
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1007/s00542-013-1899-4
