and S. Kobayashi, Chem.–Asian J., 2006, 1, 22–35; (d) M. Brivio,
W. Verboom and D. N. Reinhoudt, Lab Chip, 2006, 6, 329–344l;
(e) P. Watts and C. Wiles, Org. Biomol. Chem., 2007, 5, 727–732.
2. K. Jensen, Nature, 1998, 393, 735–737.
3. W. Ehrfeld, V. Hessel and H. Lowe, Microreactors—New Tech-
nology for Modern Chemistry, Wiley-VCH, New York, 2000.
4. G. M. Whitesides, Nature, 2006, 442, 368–373.
5. J. Yoshida, A. Nagaki, T. Iwasaki and S. Suga, Chem. Eng.
Technol., 2005, 28, 259–266.
6. A. K. Goetz, B. Scheffler, H. X. Chen, S. S. Wang, O. Suslov,
H. Xiang, O. Brustle, S. N. Roper and D. A. Steindler, Proc. Natl.
Acad. Sci. U. S. A., 2006, 103, 11063–11068.
7. A. J. deMello, Nature, 2006, 442, 394–402.
8. (a) C. C. Lee, A. Elizarov, C. Y. J. Shu, Y. S. Shin, A. N. Dooley,
J. Huang, A. Daridon, D. S. P. Wyatt, H. C. Kolb, O. N. Witte,
N. Satyamurthy, J. R. Heath, M. E. Phelps, S. R. Quake and
H. R. Tseng, Science, 2005, 310, 1793–1796; (b) G. D. Sui and
H. R. Tseng, Nano Today, 2006, 6–7; (c) J. Y. Wang, G. D. Sui,
V. P. Mocharla, R. J. Lin, M. E. Phelps, H. C. Kolb and
H. R. Tseng, Angew. Chem., Int. Ed., 2007, 45, 5276–5281;
(d) S. Hou, S. Wang, Z. T. F. Yu, N. Q. M. Zhu, J. Sun,
W.-Y. Lin, C. K.-F. Shen, X. Fang and H.-R. Tseng, Angew.
Chem., Int. Ed., 2008, 47, 1072–1075.
9. E. M. Purcell, Am. J. Phys., 1977, 45, 3–11.
10. J. P. Brody, P. Yager, R. E. Goldstein and R. H. Austin, Biophys.
J., 1996, 71, 3430–3441.
11. T. M. Squires and S. R. Quake, Rev. Mod. Phys., 2005, 77,
977–1026.
12. N. T. Nguyen and Z. G. Wu, J. Micromech. Microeng., 2005, 15,
R1.
13. V. Hessel, H. Lowe and F. Schonfeld, Chem. Eng. Sci., 2005, 60,
2479–2501.
14. F. G. Bessoth, A. J. deMello and A. Manz, Anal. Commun., 1999,
36, 213–215.
15. Y. Xu, F. G. Bessoth, J. C. T. Eijkel and A. Manz, Analyst, 2000,
125, 677–683.
16. M. C. Mitchell, V. Spikmans and A. J. de Mello, Analyst, 2001,
126, 24–27.
Fig. 2 (a) Competitive-consecutive diazo-coupling reaction between
1 and 2 were carried out in the dynamic reactor at different stream
compression ratios (a). (b) Distribution plots of 3 (P3/(2P4 + P3),
squares, dashed line) and 4 (P4/(2P4 + P3), triangles, solid line) as a
function of (c) a values and (d) focused beam widths.
17. K. Jahnisch, V. Hessel, H. Lowe and M. Baerns, Angew. Chem.,
Int. Ed., 2004, 43, 406–446.
18. Z. G. Wu and N. T. Nguyen, Biomed. Microdevices, 2005, 7,
13–20.
19. (a) H. Hisamoto, T. Saito, M. Tokeshi, A. Hibara and
experimental results, illustrating the relationship between the
stream compression ratio (a) and the resulting product dis-
tribution ratios. According to the results obtained in mixing
behavior studies (Fig. S2bw) and keeping in mind that the a
values and hydrodynamic focused beam widths are recipro-
cally related, the a values can be converted to the respective
focused beam widths. Thus Fig. 2c, where the product dis-
tribution ratios are plotted against focused beam widths,
better interprets the concept of our dynamic micromixer—i.e.,
multi-lamination beams with variable widths for controllable
mixing, allowing arbitrary control of the product distribution
of a fast competitive consecutive reaction.4,20
T.
Kitamori,
Chem.
Commun.,
2001,
2662–2663;
(b) J. R. Bourne, C. Hilber and G. Tovstiga, Chem. Eng. Com-
mun., 1985, 37, 293–314.
20. A. Nagaki, M. Togai, S. Suga, N. Aoki, K. Mae and J. Yoshida,
J. Am. Chem. Soc., 2005, 127, 11666–11675.
21. J. R. Bourne, O. M. Kut and J. Lenzner, Ind. Eng. Chem. Res.,
1992, 31, 949–958.
22. R. J. Ott and P. Rys, Helv. Chim. Acta, 1975, 58, 2074–2093.
23. H. Okamoto, Kagakusochi, 2004, 9, 74.
24. P. Rys, Acc. Chem. Res., 1976, 9, 345–351.
25. P. Rys, Angew. Chem., Int. Ed. Engl., 1977, 16, 807–884.
26. M. C. Mitchell, V. Spikmans, A. Manz and A. J. de Mello,
J. Chem. Soc., Perkin Trans. 1, 2001, 514–518.
27. J. B. Knight, A. Vishwanath, J. P. Brody and R. H. Austin, Phys.
Rev. Lett., 1998, 80, 3863–3866.
28. X. L. Zhu, G. Liu, Y. H. Guo and Y. C. Tian, Microsyst. Technol.,
2007, 13, 403–407.
29. The isolation stream is important to prevent premixing of the
reagents prior to hydrodynamic focusing thus having control of
the reagents’ mixing time.
30. H. Y. Park, X. Qiu, E. Rhoades, J. Korlach, L. W. Kwok,
W. R. Zipfel, W. W. Webb and L. Pollack, Anal. Chem., 2006,
78, 4465–4473.
In conclusion, the usefulness of the dynamic microreactor
was confirmed by achieving control over the disguised chemi-
cal selectivity of the diazo reaction. It is conceivable that this
dynamic micromixer can also provide a powerful platform to
study particle and quantum dot formation, chemical and
biological reaction kinetics and conduct biological analyses,
all of which require precise control in reaction kinetics.
This research was supported by the DOD-Defense Threat
Reduction Agency (W911NF0610243), the NIH-NCI Nano-
Systems Biology Cancer Center (U54A119347). M.S. grate-
fully acknowledges support by the NSF-PREM Program
(Award No. 0351848).
31. The shape of the reagent/isolation streams in Fig. 1d not only
depends on the compression of the sheath streams but also that the
shape of the channel reduces at the entrance of each inlet junction.
32. R. F. Ismagilov, A. D. Stroock, P. J. A. Kenis, G. Whitesides and
H. A. Stone, Appl. Phys. Lett., 2000, 76, 2376–2378.
33. When one-step sheath flow compression was applied to generate
Notes and references
1. For reviews see (a) P. Watts and C. Wiles, Chem. Commun., 2007,
443–467; (b) K. Geyer, J. D. C. Codee and P. H. Seeberger,
Chem.–Eur. J., 2006, 12, 8434–8442; (c) J. Kobayashi, Y. Mori
a focused stream with a width smaller than 4 mm, the
insatiability manifested in the form of shaky or discontinuous
focused streams.
ꢂc
This journal is The Royal Society of Chemistry 2008
3428 | Chem. Commun., 2008, 3426–3428