Molecular transport technology is one of the hottest topics in micro- and nanofluidics. Target molecules are often transported by electric forces, e.g. capillary electrophoresis (EP), gel EP, biological and artificial nanopores. On the other hand, such methods are sometimes disturbed by surrounding environments because the surface effects tend to be prominent. The surface charges on the channel walls cause peculiar liquid flows in micro- and nanochannels. Thus, the isolation of electrophoretic transport from the fluidic effects is important to achieve the precise control of targets in confined spaces. In this study, a novel technique to control the transport of microparticles is proposed, where a liquid flow is involved by applying electric body forces. The direction of electrically charged microparticles is controlled by the electric forces not only on the particle but also in the liquid. Herein, an electrohydrodynamic flow is applied by preparing electrically polarised solutions. In this setup, the transport direction of particles can be changed depending on the electric forces by excessive ions, which is estimated by measuring electric conductivity.

References

1. 1)
  - 11. Liu, Y., Fanguy, J.C., Bledsoe, J.M., et al: ‘Dynamic coating using polyelectrolyte multilayers for chemical control of electroosmotic flow in capillary electrophoresis microchips’, Anal. Chem., 2000, 72, pp. 5939–5944 (doi: 10.1021/ac000932l).
2. 2)
  - 22. Doi, K., Yano, A., Kawano, S.: ‘Electrohydrodynamic flow through a 1 mm2 cross-section pore placed in an ion-exchange membrane’, J. Phys. Chem. B, 2015, 119, pp. 228–237 (doi: 10.1021/jp5071538).
3. 3)
  - 19. Trau, M., Saville, D.A., Aksay, I.A.: ‘Assembly of colloidal crystals at electrode interfaces’, Langumuir, 1997, 13, pp. 6375–6381 (doi: 10.1021/la970568u).
4. 4)
  - 20. Ristenpart, W.D., Aksay, I.A., Saville, D.A.: ‘Assembly of colloidal aggregates by electrohydrodynamic flow: kinetic experiments and scaling analysis’, Phys. Rev. E, 2004, 69, pp. 021405-1–021405-8 (doi: 10.1103/PhysRevE.69.021405).
5. 5)
  - 8. Wang, W., Zhou, F., Zhao, L., et al: ‘Measurement of electroosmotic flow in capillary and microchip electrophoresis’, J. Chromatogr. A, 2007, 1170, pp. 1–8 (doi: 10.1016/j.chroma.2007.08.083).
6. 6)
  - 4. Meacher, R.J., Won, J.-I., McCormick, L.C., et al: ‘End-labeled free solution electrophoresis of DNA’, Electrophoresis, 2005, 26, pp. 331–350 (doi: 10.1002/elps.200410219).
7. 7)
  - 18. Saville, D.A.: ‘Electrohydrodynamics: the Taylor-Melcher leaky dielectric model’, Annu. Rev. Fluid Mech., 1997, 29, pp. 27–64 (doi: 10.1146/annurev.fluid.29.1.27).
8. 8)
  - 27. Kirby B.J., , Hasselbrink, E.F.Jr.: ‘Zeta potential of microfluidic substrates: 1. Theory, experimental techniques, and effects on separations’, Electrophoresis, 2004, 25, pp. 187–202 (doi: 10.1002/elps.200305754).
9. 9)
  - 17. Melcher, J.R., Taylor, G.I.: ‘Electrohydrodynamics: a review of the role of interfacial shear stresses’, Annu. Rev. Fluid Mech., 1969, 1, pp. 111–146 (doi: 10.1146/annurev.fl.01.010169.000551).
10. 10)
  - 23. Yano, A., Doi, K., Kawano, S.: ‘Observation of electrohydrodynamic flow through a pore in ion-exchange membrane’, Int. J. Chem. Eng. Appl., 2015, 6, pp. 254–257.
11. 11)
  - 1. Hanasaki, I., Nagura, R., Kawano, S.: ‘Coarse-grained picture of Brownian motion in water: role of size and interaction distance range on the nature of randomness’, J. Chem. Phys., 2015, 142, pp. 104301-1–104301-11 (doi: 10.1063/1.4913748).
12. 12)
  - 2. Wang, Y.-C., Han, J.: ‘Pre-binding dynamic range and sensitivity enhancement for immuno-sensors using nanofluidic preconcentrator’, Lab Chip, 2008, 8, pp. 392–394 (doi: 10.1039/b717220f).
13. 13)
  - 5. Tsutsui, M., Taniguchi, M., Yokota, K., et al: ‘Identifying single nucleotides by tunnelling current’, Nat. Nanotech., 2010, 5, pp. 286–290 (doi: 10.1038/nnano.2010.42).
14. 14)
  - 21. Ristenpart, W.D., Aksay, I.A., Saville, D.A.: ‘Electrohydrodynamic flow around a colloidal particle near an electrode with an oscillating potential’, J. Fluid Mech., 2007, 575, pp. 83–109 (doi: 10.1017/S0022112006004368).
15. 15)
  - 10. Masselter, S.M., Zemann, A.J.: ‘Influence of buffer electrolyte pH on the migration behavior of phenolic compounds in co-electroosmotic capillary electrophoresis’, J. Chromatogr. A, 1995, 693, pp. 359–365 (doi: 10.1016/0021-9673(94)01112-R).
16. 16)
  - 26. Mangelsdorf, C.S., White, L.R.: ‘Effects of stern-layer conductance on electrokinetic transport properties of colloidal particles’, J. Chem. Soc. Faraday Trans., 1990, 86, pp. 2859–2870 (doi: 10.1039/ft9908602859).
17. 17)
  - 24. Henry, D.C.: ‘The cataphoresis of suspended particles. part I- the equation of caraphoresis’, Proc. R. Soc. London, Ser. A, 1931, 133, pp. 106–129 (doi: 10.1098/rspa.1931.0133).
18. 18)
  - 14. Guan, W., Reed, M.A.: ‘Electric field modulation of the membrane potential in solid-stateion channels’, Nano Lett., 2012, 12, pp. 6441–6447 (doi: 10.1021/nl303820a).
19. 19)
  - 6. Daiguji, H., Yang, P., Majumdar, A.: ‘Ion transport in nanofluidic channels’, Nano Lett., 2004, 4, pp. 137–142 (doi: 10.1021/nl0348185).
20. 20)
  - 1. Schoch, R.B., Han, J., Renaud, P.: ‘Transport phenomena in nanofluidics’, Rev. Mod. Phys., 2008, 80, pp. 839–883 (doi: 10.1103/RevModPhys.80.839).
21. 21)
  - 16. Fütterer, C., Minc, N., Bormuth, V., et al: ‘Injection and flow control system for microchannels’, Lab Chip, 2004, 4, pp. 351–356 (doi: 10.1039/B316729A).
22. 22)
  - 3. Song, H., Wang, Y., Garson, C., et al: ‘Nafion-film-based micro-nanofluidic device dor concurrent DNA preconcentration and separation in free solution’, Microfluid. Nanofluid., 2014, 17, pp. 693–699 (doi: 10.1007/s10404-014-1357-3).
23. 23)
  - 25. Midmore, B.R., Hunter, R.J.: ‘The effect of electrolyte concentration and co-ion type on the potential of polystyrene latices’, J. Coll. Interface Sci., 1988, 122, pp. 521–529 (doi: 10.1016/0021-9797(88)90387-6).
24. 24)
  - 15. He, Y., Tsutusi, M., Fan, C., et al: ‘Gate manipulation of DNA capture into nanopores’, ACS Nano, 2011, 5, pp. 8391–8397 (doi: 10.1021/nn203186c).
25. 25)
  - 12. Sola, L., Chiari, M.: ‘Modulation of electroosmotic flow in capillary electrophoresis using functional polymer coatings’, J. Chromatogr. A, 2012, 1270, pp. 324–329 (doi: 10.1016/j.chroma.2012.10.039).
26. 26)
  - 13. He, Y., Tsutusi, M., Fan, C., et al: ‘Controlling DNA translocation through gate modulation of nanopore wall surface charges’, ACS Nano, 2011, 5, pp. 5509–5518 (doi: 10.1021/nn201883b).
27. 27)
  - 28. Kirby B.J., , Hasselbrink, E.F.Jr.: ‘Zeta potential of microfluidic substrates: 2. Data for polymers’, Electrophoresis, 2004, 25, pp. 203–213 (doi: 10.1002/elps.200305755).
28. 28)
  - 9. Mendes, A., Branco, L.C., Morais, C., et al: ‘Electroosmotic flow modulation in capillary electrophoresis by organic cations from ionic liquids’, Electrophoresis, 2012, 33, pp. 1182–1190 (doi: 10.1002/elps.201100486).

Characterisation of microparticle transport driven by ionic current conditions in electrically polarised aqueous solutions

References

Related content