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Title: Monodisperse alginate microgel formation in a three-dimensional microfluidic droplet generator

Journal Article · · Biomicrofluidics
DOI:https://doi.org/10.1063/1.4765337· OSTI ID:1067291
 [1];  [2];  [3];  [4]
  1. Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
  2. Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
  3. Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA; Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
  4. Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA; Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA; Department of Electrical Engineering and Computer Science, University of Tennessee Knoxville, Knoxville, Tennessee 37996, USA

Droplet based microfluidic systems provide an ideal platform for partitioning and manipulating aqueous samples for analysis. Identifying stable operating conditions under which droplets are generated is challenging yet crucial for real-world applications. A novel three-dimensional microfluidic platform that facilitates the consistent generation and gelation of alginate-calcium hydrogel microbeads for microbial encapsulation, over a broad range of backing pressures, in the absence of surfactants, is described. The unique three-dimensional design of the fluidic network utilizes a height difference at the junction between the aqueous sample injection and organic carrier channels to induce droplet formation via a surface tension enhanced self-shearing mechanism. Combined within a flow-focusing geometry, under constant pressure control, this arrangement facilitates predictable generation of droplets over a much broader range of operating conditions than conventional two-dimensional systems. The impact of operating pressures and geometry on droplet gelation, aqueous and organic material flow rates, microbead size and bead generation frequency are described. The system presented provides a robust platform for encapsulating single microbes in complex mixtures into individual hydrogel beads, and provides the foundation for the development of a complete system for sorting and analyzing microbes at the single cell level.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
Sponsoring Organization:
Work for Others (WFO)
DOE Contract Number:
DE-AC05-00OR22725
OSTI ID:
1067291
Journal Information:
Biomicrofluidics, Vol. 6, Issue 4; ISSN 1932-1058
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English