J. Cooper McDonald
Harvard University
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Featured researches published by J. Cooper McDonald.
Analytical Chemistry | 1998
David C. Duffy; J. Cooper McDonald; and Olivier J. A. Schueller; George M. Whitesides
This paper describes a procedure that makes it possible to design and fabricate (including sealing) microfluidic systems in an elastomeric material [Formula: see text] poly(dimethylsiloxane) (PDMS) [Formula: see text] in less than 24 h. A network of microfluidic channels (with width >20 μm) is designed in a CAD program. This design is converted into a transparency by a high-resolution printer; this transparency is used as a mask in photolithography to create a master in positive relief photoresist. PDMS cast against the master yields a polymeric replica containing a network of channels. The surface of this replica, and that of a flat slab of PDMS, are oxidized in an oxygen plasma. These oxidized surfaces seal tightly and irreversibly when brought into conformal contact. Oxidized PDMS also seals irreversibly to other materials used in microfluidic systems, such as glass, silicon, silicon oxide, and oxidized polystyrene; a number of substrates for devices are, therefore, practical options. Oxidation of the PDMS has the additional advantage that it yields channels whose walls are negatively charged when in contact with neutral and basic aqueous solutions; these channels support electroosmotic pumping and can be filled easily with liquids with high surface energies (especially water). The performance of microfluidic systems prepared using this rapid prototyping technique has been evaluated by fabricating a miniaturized capillary electrophoresis system. Amino acids, charge ladders of positively and negatively charged proteins, and DNA fragments were separated in aqueous solutions with this system with resolution comparable to that obtained using fused silica capillaries.
Electrophoresis | 2000
J. Cooper McDonald; David C. Duffy; Janelle R. Anderson; Daniel T. Chiu; Hongkai Wu; Olivier Schueller; George M. Whitesides
Microfluidic devices are finding increasing application as analytical systems, biomedical devices, tools for chemistry and biochemistry, and systems for fundamental research. Conventional methods of fabricating microfluidic devices have centered on etching in glass and silicon. Fabrication of microfluidic devices in poly(dimethylsiloxane) (PDMS) by soft lithography provides faster, less expensive routes than these conventional methods to devices that handle aqueous solutions. These soft‐lithographic methods are based on rapid prototyping and replica molding and are more accessible to chemists and biologists working under benchtop conditions than are the microelectronics‐derived methods because, in soft lithography, devices do not need to be fabricated in a cleanroom. This paper describes devices fabricated in PDMS for separations, patterning of biological and nonbiological material, and components for integrated systems.
Analytical Chemistry | 2000
Janelle R. Anderson; Daniel T. Chiu; Rebecca J. Jackman; Oksana Cherniavskaya; J. Cooper McDonald; Hongkai Wu; Sue Whitesides; George M. Whitesides
Proceedings of the National Academy of Sciences of the United States of America | 1999
Shuichi Takayama; J. Cooper McDonald; Emanuele Ostuni; Mici-Iael N. Liang; Paul J. A. Kenis; Rustem F. Ismagilov; George M. Whitesides
Analytical Chemistry | 2001
Michael L. Chabinyc; Daniel T. Chiu; J. Cooper McDonald; Abraham D. Stroock; James F. Christian; and Arieh M. Karger; George M. Whitesides
Analytical Chemistry | 2002
J. Cooper McDonald; Michael L. Chabinyc; Steven J. Metallo; Janelle R. Anderson; and Abraham D. Stroock; George M. Whitesides
Science | 1998
Feng Gai; K. C. Hasson; J. Cooper McDonald; Philip A. Anfinrud
Analytical Chemistry | 2001
J. Cooper McDonald; and Steven J. Metallo; George M. Whitesides
Analytical Chemistry | 2001
Ravi S. Kane; Peter T. Glink; Robert G. Chapman; J. Cooper McDonald; Pamela K. Jensen; Hongying Gao; Ljiljana Paša-Tolić; and Richard D. Smith; George M. Whitesides
Archive | 2002
Janelle R. Anderson; Daniel T. Chiu; Insung S. Choi; Noo Li Jeon; J. Cooper McDonald; Steven J. Metallo; Howard A. Stone; Christopher J. Wargo; George M. Whitesides; Hongkai Wu