Microstructure-induced helical vortices allow single-stream and long-term inertial focusing

Aram J. Chung, Dianne Pulido, Justin C. Oka, Hamed Amini, Mahdokht Masaeli, Dino Di Carlo

Research output: Contribution to journalArticlepeer-review

79 Citations (Scopus)


Fluid inertia has been used to position microparticles in confined channels because it leads to precise and predictable particle migration across streamlines in a high-throughput manner. To focus particles, typically two inertial effects have been employed: inertial migration of particles in combination with geometry-induced secondary flows. Still, the strong scaling of inertial effects with fluid velocity or channel flow rate have made it challenging to design inertial focusing systems for single-stream focusing using large-scale microchannels. Use of large-scale microchannels (≥100 μm) reduces clogging over long durations and could be suitable for non-single-use flow cells in cytometry systems. Here, we show that microstructure-induced helical vortices yield single-stream focusing of microparticles with continuous and robust operation. Numerical and experimental results demonstrate how structures contribute to improve focusing in these larger channels, through controllable cross-stream particle migration, aided by locally-tuned secondary flows from sequential obstacles that act to bring particles closer to a single focusing equilibrium position. The large-scale inertial focuser developed here can be operated in a high-throughput manner with a maximum throughput of approximately 13000 particles per s.

Original languageEnglish
Pages (from-to)2942-2949
Number of pages8
JournalLab on a Chip
Issue number15
Publication statusPublished - 2013 Aug 7
Externally publishedYes

ASJC Scopus subject areas

  • Bioengineering
  • Biochemistry
  • Chemistry(all)
  • Biomedical Engineering


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