PMID- 21244017
OWN - NLM
STAT- MEDLINE
DCOM- 20110603
LR  - 20131121
IS  - 1520-6882 (Electronic)
IS  - 0003-2700 (Linking)
VI  - 83
IP  - 4
DP  - 2011 Feb 15
TI  - Monitoring a reaction at submillisecond resolution in picoliter volumes.
PG  - 1462-8
LID - 10.1021/ac103234a [doi]
AB  - Well-established rapid mixing techniques such as stopped-flow have been used to 
      push the dead time for kinetic experiments down to a few milliseconds. However, 
      very fast reactions are difficult to resolve below this limit. We now outline an 
      approach that provides access to ultrafast kinetics but does not rely on active 
      mixing at all. Here, the reagents are compartmentalized into water-in-oil 
      emulsion microdroplets (diameter  approximately 50 mum) that are statically arrayed in pairs, 
      resting side-by-side in a well feature of a poly(dimethylsiloxane) (PDMS) device. 
      A reaction between the contents of two droplets arrayed in such a holding trap is 
      initiated by droplet fusion that is brought about by electrocoalescence and known 
      to occur on a time scale of about 100 mus. A reaction between the reactants 
      (Fe(3+) and SCN(-)) is monitored by image analysis measuring the product 
      formation in the newly merged drop in both space and time, by use of a fast 
      camera. A comparison of the concentration field of the reaction product with the 
      output of a reaction-diffusion system of equations yields a rate constant k  approximately  3 x 
      10(4) M(-3).s(-1). Since reaction and diffusion are formally included in the 
      mathematical model, measurements can proceed immediately after the drop fusion, 
      removing the need to allow time for mixing. This approach is different from 
      existing methodologies, for example, experiments in a conventional stopped-flow 
      apparatus but also electrofusion of moving droplets where contents are mixed by 
      chaotic advection before a reaction is monitored. Our analysis makes kinetics 
      accessible that are several times faster than techniques that have to allow time 
      for mixing.
FAU - Huebner, Ansgar M
AU  - Huebner AM
AD  - Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom.
FAU - Abell, Chris
AU  - Abell C
FAU - Huck, Wilhelm T S
AU  - Huck WT
FAU - Baroud, Charles N
AU  - Baroud CN
FAU - Hollfelder, Florian
AU  - Hollfelder F
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20110118
PL  - United States
TA  - Anal Chem
JT  - Analytical chemistry
JID - 0370536
RN  - 0 (Dimethylpolysiloxanes)
RN  - 0 (Oils)
RN  - 059QF0KO0R (Water)
RN  - 63148-62-9 (baysilon)
SB  - IM
MH  - Diffusion
MH  - Dimethylpolysiloxanes/chemistry
MH  - Equipment Design
MH  - Hydrodynamics
MH  - Kinetics
MH  - Microarray Analysis/instrumentation/*methods
MH  - Oils/chemistry
MH  - Water/chemistry
EDAT- 2011/01/20 06:00
MHDA- 2011/06/04 06:00
CRDT- 2011/01/20 06:00
PHST- 2011/01/20 06:00 [entrez]
PHST- 2011/01/20 06:00 [pubmed]
PHST- 2011/06/04 06:00 [medline]
AID - 10.1021/ac103234a [doi]
PST - ppublish
SO  - Anal Chem. 2011 Feb 15;83(4):1462-8. doi: 10.1021/ac103234a. Epub 2011 Jan 18.