Microfluidic active sorting of DNA molecules labeled with single quantum dots using flow switching by a hydrogel sol-gel transition

Mai Haneoka, Yoshitaka Shirasaki, Hirokazu Sugino, Tokihiko Aoki, Takahiro Arakawa, Kazuto Ozaki, Dong Hyun Yoon, Noriyuki Ishii, Ryo Iizuka, Shuichi Shoji*, Takashi Funatsu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)


The fluorescence-activated cell sorter instrument has contributed significantly to life sciences. However, this instrument has limitations including the inability to detect and hence sort nanometer-sized particles such as quantum dots (Qdots) and virus particles. Here, a microfluidic device for analyzing and sorting nanometer-sized particles has been developed. To achieve sensitive detection, the sample flow was hydrodynamically sheathed and effectively excited with a focused laser beam. Flow control was performed by a sol-gel transition of a thermoreversible gelation polymer. This flow control approach enabled us to restrict the lateral diffusion of nanometer-sized particles and to sort the particles in ∼10 μm channels. Single Qdots with diameters of ∼10 nm were detected at a linear flow velocity of about 4 mm/s, and the Qdots were successfully sorted with the sorting system. Using the developed sorter in an application, Qdot-labeled actin DNA was separated from unwanted glyceraldehyde-3-phosphate dehydrogenase DNA, and the purity of Qdot-labeled actin DNA increased following the sorting. This study represents the first example of active separation of biomolecules labeled with single 10 nm-sized particles of Qdots.

Original languageEnglish
Pages (from-to)314-320
Number of pages7
JournalSensors and Actuators, B: Chemical
Issue number1
Publication statusPublished - 2011 Nov 28
Externally publishedYes


  • DNA
  • Microfluidics
  • On-chip sorter
  • Quantum dot
  • Separation
  • Thermo-reversible gelation polymer

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrical and Electronic Engineering
  • Materials Chemistry


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