Microfluidic large-scale integration

Science

Volumn 298, Issue 5593, 2002, Pages 580-584

  Thorsen, Todd ^a   Maerkl, Sebastian J ^a   Quake, Stephen R ^a  

^a California Institute of Technology   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ARRAYS; VALVES (MECHANICAL);

MICROFLUIDIC CHIPS;

INTEGRATED CIRCUITS;

CYTOCHROME C PEROXIDASE; GREEN FLUORESCENT PROTEIN; RECOMBINANT ENZYME;

ELECTRONIC EQUIPMENT;

ARTICLE; CONTROLLED STUDY; DEVICE; ELECTRONICS; ENGINEERING; ESCHERICHIA COLI; FLUORESCENCE; LOGIC; MEMORY CONSOLIDATION; MICROCHIP; MICROFLUIDIC CHIP; NONHUMAN; PRIORITY JOURNAL; TECHNOLOGY;

BIOCHEMISTRY; BROMPHENOL BLUE; COLORING AGENTS; COMPUTERS; CYTOCHROME-C PEROXIDASE; ELECTRONICS; ESCHERICHIA COLI; GENE EXPRESSION PROFILING; GREEN FLUORESCENT PROTEINS; LUMINESCENT PROTEINS; MINIATURIZATION; PRESSURE; SILICONES;

ESCHERICHIA COLI;

EID: 0037131390     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.1076996     Document Type: Article

References (19)

1. T. R. Reid, The Chip: How Two Americans Invented the Microchip and Launched a Revolution (Simon & Schuster, New York, 1984).
2. A. G. Hadd, S. C. Jacobson, J. M. Ramsey, Anal. Chem. 71, 5206 (1999).
3. D. J. Harrison et al., Science 261, 895 (1993).
4. P. C. H. Li, D. J. Harrison, Anal. Chem. 69, 1564 (1997).
5. A. G. Hadd, D. E. Raymond, J. W. Haliwell, S. C. Jacobson, S. C. Ramsey, Anal. Chem. 69, 3407 (1997).
6. E. T. Lagally, I. Medintz, R. A. Mathies, Anal. Chem. 73, 565 (2001).
7. J. Khandurina et al., Anal. Chem. 72, 2995 (2000).
8. E. Eteshola, D. Leckband, Sens. Actua. B 72, 129 (2001).
9. J. Wang, A. Ibanez, M. P. Chatrathi, A. Escarpa, Anal. Chem. 73, 5323 (2001).
10. M. A. Unger, H.-P. Chou, T. Thorsen, A. Scherer, S. R. Quake, Science 288, 113 (2000).
11. Master molds for the microfluidic channels are made by spin-coating positive photoresist (Shipley SJR 5740) on silicon (9 μm high) and patterning them with high-resolution (3386 dpi) transparency masks. The channels on the photoresist molds are rounded at 120°C for 20 min to create a geometry that allows full valve closure. The devices were fabricated by bonding together two layers of two-part cure silicone (Dow Corning Sylgard 184) cast from the photoresist molds. The bottom layer of the device, containing the flow channels, is spin-coated with 20:1 part A:B Sylgard at 2500 rpm for 1 min. The resulting silicone layer is ∼30 μm thick. The top layer of the device, containing the control channels, is cast as a thick layer (∼0.5 cm thick) with 5:1 part A:B Sylgard using a separate mold. The two layers are initially cured for 30 min at 80°C. Control channel interconnect holes are then punched through the thick layer (released from the mold), after which it is sealed, channel side down, on the thin layer, aligning the respective channel networks. Bonding between the assembled layers is accomplished by curing the devices for an additional 45 to 60 min at 80°C. The resulting multilayer devices are cut to size and mounted on RCA cleaned No. 1, 25 mm square glass coverslips, or onto coverslips spin-coated with 5:1 part A:B Sylgard at 5000 rpm, and cured at 80°C for 30 min, followed by incubation at 80°C overnight.
12. L. Buchaillot, E. Farnault, M. Hoummady, H. Fujita, Jpn. J. Appl. Phys. 2 36, L794 (1997).
13. The control channels are dead end-filled with water before actuation with pneumatic pressure; the compressed air at the ends of the channels is forced into the bulk porous silicone. This procedure eliminates gas transfer into the flow layer upon valve actuation, as well as evaporation of the liquid contained in the flow layer.
14. H. P. Chou, C. S. Spence, A. Scherer, S. R. Quake, Proc. Natl. Acad. Sci. U.S.A. 96, 11 (1999).
15. V. Linder, E. Verpoorte, W. Thormann, N. F. de Rooij, H. Sigrist, Anal. Chem. 73, 4181 (2001).
16. T. Yang, S. Jung, H. Mao, P. S. Cremer, Anal. Chem. 73, 165 (2001).
17. D. C. Duffy, J. C. MacDonald, O. J. A. Schueller, G. M. Whitesides, Anal. Chem. 70, 4974 (1998).
18. B. A. Grzybowski, R. Haag, N. Bowden, G. M. Whitesides, Anal. Chem. 70, 4645 (1998).
19. We thank M. Enzelberger, C. Hansen, M. Adams, and M. Unger for helpful discussions. Supported in part by Army Research Office grant DAAD19-00-1-0392 and by the DARPA Bioflips program.