Microfluidic generation of aqueous two-phase system (ATPS) droplets by controlled pulsating inlet pressures.

Lab Chip 2015 Jun;15(11):2437-44

Ryerson University, Mechanical and Industrial Engineering, Toronto, Canada.

We present a technique that generates droplets using ultralow interfacial tension aqueous two-phase systems (ATPS). Our method combines a classical microfluidic flow focusing geometry with precisely controlled pulsating inlet pressure, to form monodisperse ATPS droplets. The dextran (DEX) disperse phase enters through the central inlet with variable on-off pressure cycles controlled by a pneumatic solenoid valve. The continuous phase polyethylene glycol (PEG) solution enters the flow focusing junction through the cross channels at a fixed flow rate. The on-off cycles of the applied pressure, combined with the fixed flow rate cross flow, make it possible for the ATPS jet to break up into droplets. We observe different droplet formation regimes with changes in the applied pressure magnitude and timing, and the continuous phase flow rate. We also develop a scaling model to predict the size of the generated droplets, and the experimental results show a good quantitative agreement with our scaling model. Additionally, we demonstrate the potential for scaling-up of the droplet production rate, with a simultaneous two-droplet generating geometry. We anticipate that this simple and precise approach to making ATPS droplets will find utility in biological applications where the all-biocompatibility of ATPS is desirable.

Download full-text PDF

Source
http://dx.doi.org/10.1039/c5lc00217fDOI Listing
June 2015
26 Reads

Publication Analysis

Top Keywords

flow rate
12
atps droplets
12
controlled pulsating
8
pulsating inlet
8
continuous phase
8
scaling model
8
flow focusing
8
fixed flow
8
applied pressure
8
aqueous two-phase
8
flow
6
droplets
6
atps
6
central inlet
4
valve continuous
4
generated droplets
4
enters central
4
solenoid valve
4
phase polyethylene
4
model predict
4

References

(Supplied by CrossRef)

Walter et al.
1994

Asenjo et al.
J. Chromatogr. A 2011

Albertsson et al.
1986

Walter et al.
Anal. Biochem. 1991

Merchuk et al.
J. Chromatogr. B: Biomed. Sci. Appl. 1998

Sivars et al.
Biochim. Biophys. Acta, Gen. Subj. 2000

Kumar et al.
Biotechnol. Bioeng. 2001

Yamada et al.
Biotechnol. Bioeng. 2004

Frampton et al.
Biomed. Microdevices 2011

Yaguchi et al.
Analyst 2010

Tavana et al.
Nat. Mater. 2009

Similar Publications