Abstract
We present herein microfluidic systems to continuously focus the positions of flowing particles onto the center of a microchannel, which is indispensable to various applications for manipulating particles or cells such as flow cytometry and particle-based bioassay. A scheme called ‘hydrodynamic filtration’ is employed to repeatedly split fluid flows from a main stream, while remaining particles in the main stream. By re-injecting the split flows into the main channel, these flows work as sheath flows, focusing the positions of the particles onto the center of the microchannel without the help of sheath flows or complicated devices generating physical forces. In this study, we proposed two schemes, and compared the focusing efficiencies between the two schemes using particles 5.0 μm in diameter. Also, we confirmed that the flow speed did not affect the focusing efficiency, demonstrating the versatility and applicability of the presented systems.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Bird RB, Stewart WE, Lightfoot EN (2002) Transport phenomena, 2nd edn. Wiley, New York, p 51
Constantinescu VN (1995) Laminar viscous flow. Springer, New York, pp 109–137
Di Carlo D, Irimia D, Tompkins RG, Toner M (2007) Continuous inertial focusing, ordering, and separation of particles in microchannels. Proc Natl Acad Sci USA 104:18892–18897
Duffy DC, McDonald JC, Schueller OJA, Whitesides GM (1998) Rapid prototyping of microfluidic systems in poly(dimethylsiloxane). Anal Chem 70:4974–4984
Knight JB, Vishwanath A, Brody JP, Austin RH (1998) Hydrodynamic focusing on a silicon chip: mixing nanoliters in microseconds. Phys Rev Lett 80:3863–3866
McClain MA, Culbertson CT, Jacobson SC, Ramsey JM (2001) Flow cytometry of Escherichia coli on microfluidic devices. Anal Chem 73:5334–5338
Rodriguez-Trujillo R, Mills CA, Samitier J, Gomila G (2007) Low cost micro-Coulter counter with hydrodynamic focusing. Microfluid Nanofluid 3:171–176
Schrum DP, Culbertson CT, Jacobson SC, Ramsey JM (1999) Microchip flow cytometry using electrokinetic focusing. Anal Chem 71:4173–4177
Shi JJ, Mao XL, Ahmed D, Colletti A, Huang TJ (2008) Focusing microparticles in a microfluidic channel with standing surface acoustic waves (SSAW). Lab Chip 8:221–223
Stiles T, Fallon R, Vestad T, Oakey J, Marr DWM, Squier J, Jimenez R (2005) Hydrodynamic focusing for vacuum-pumped microfluidics. Microfluid Nanofluid 1:280–283
Wang Z, El-Ali J, Engelund M, Gotsaed T, Perch-Nielsen IR, Mogensen KB, Snakenborg D, Kutter JP, Wolff A (2004) Measurements of scattered light on a microchip flow cytometer with integrated polymer based optical elements. Lab Chip 4:372–377
Wang TH, Peng YH, Zhang CY, Wong PK, Ho CM (2005) Single-molecule tracing on a fluidic microchip for quantitative detection of low-abundance nucleic acids. J Am Chem Soc 127:5354–5359
Wang L, Flanagan LA, Jeon NL, Monuki E, Lee AP (2007) Dielectrophoresis switching with vertical sidewall electrodes for microfluidic flow cytometry. Lab Chip 7:1114–1120
Wolff A, Perch-Nielsen IR, Larsen UD, Friis P, Goranovic G, Poulsen CR, Kutter JP, Telleman P (2003) Integrating advanced functionality in a microfabricated high-throughput fluorescent-activated cell sorter. Lab Chip 3:22–27
Xuan XC, Li DQ (2005) Focused electrophoretic motion and selected electrokinetic dispensing of particles and cells in cross-microchannels. Electrophoresis 26:3552–3560
Yamada M, Seki M (2005) Hydrodynamic filtration for on-chip particle concentration and classification utilizing microfluidics. Lab Chip 5:1233–1239
Yamada M, Seki M (2006) Microfluidic particle sorter employing flow splitting and recombining. Anal Chem 78:1357–1362
Yamada M, Kano K, Tsuda Y, Kobayashi J, Yamato M, Seki M, Okano T (2007) Microfluidic devices for size-dependent separation of liver cells. Biomed Microdevices 9:637–645
Yamada M, Kobayashi J, Yamato M, Seki M, Okano T (2008) Millisecond treatment of cells using microfluidic devices via two-step carrier-medium exchange. Lab Chip 8:772–778
Acknowledgments
This research was supported in part by Grants-in-aid for research fellows from Japan Society for Promotion of Science (JSPS) and for Scientific Research A (20241031) from the Ministry of Education, Sports, Science, and Culture of Japan.
Author information
Authors and Affiliations
Corresponding author
Electronic supplementary material
Rights and permissions
About this article
Cite this article
Aoki, R., Yamada, M., Yasuda, M. et al. In-channel focusing of flowing microparticles utilizing hydrodynamic filtration. Microfluid Nanofluid 6, 571–576 (2009). https://doi.org/10.1007/s10404-008-0334-0
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10404-008-0334-0