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Fabrication of poly(ethylene glycol) hydrogel microstructures using photolithographyThe fabrication of hydrogel microstructures based upon poly(ethylene glycol) diacrylates, dimethacrylates, and tetraacrylates patterned photolithographically on silicon or glass substrates is described. A silicon/silicon dioxide surface was treated with 3-(trichlorosilyl)propyl methacrylate to form a self-assembled monolayer (SAM) with pendant acrylate groups. The SAM presence on the surface was verified using ellipsometry and time-of-flight secondary ion mass spectrometry. A solution containing an acrylated or methacrylated poly(ethylene glycol) derivative and a photoinitiator (2,2-dimethoxy-2-phenylacetophenone) was spin-coated onto the treated substrate, exposed to 365 nm ultraviolet light through a photomask, and developed with either toluene, water, or supercritical CO2. As a result of this process, three-dimensional, cross-linked PEG hydrogel microstructures were immobilized on the surface. Diameters of cylindrical array members were varied from 600 to 7 micrometers by the use of different photomasks, while height varied from 3 to 12 micrometers, depending on the molecular weight of the PEG macromer. In the case of 7 micrometers diameter elements, as many as 400 elements were reproducibly generated in a 1 mm2 square pattern. The resultant hydrogel patterns were hydrated for as long as 3 weeks without delamination from the substrate. In addition, micropatterning of different molecular weights of PEG was demonstrated. Arrays of hydrogel disks containing an immobilized protein conjugated to a pH sensitive fluorophore were also prepared. The pH sensitivity of the gel-immobilized dye was similar to that in an aqueous buffer, and no leaching of the dye-labeled protein from the hydrogel microstructure was observed over a 1 week period. Changes in fluorescence were also observed for immobilized fluorophore labeled acetylcholine esterase upon the addition of acetyl acholine.
Document ID
20040087975
Acquisition Source
Johnson Space Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Revzin, A.
(College Station Texas 77843-3122, United States)
Russell, R. J.
Yadavalli, V. K.
Koh, W. G.
Deister, C.
Hile, D. D.
Mellott, M. B.
Pishko, M. V.
Date Acquired
August 21, 2013
Publication Date
September 4, 2001
Publication Information
Publication: Langmuir : the ACS journal of surfaces and colloids
Volume: 17
Issue: 18
ISSN: 0743-7463
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: NAG9-1277
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Life Sciences Technologies
Non-NASA Center

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