Ultraviolet Photolithographic Development of Polyphosphazene Hydrogel Microstructures for Potential Use in Microarray Biosensors

• Published in: Chemistry of materials Vol. 18; no. 3; pp. 609 - 613
• Main Authors: Allcock, Harry R, Phelps, Mwita V. B, Barrett, Eric W, Pishko, Michael V, Koh, Won-Gun
• Format: Journal Article
• Language: English
• Published: American Chemical Society 07.02.2006
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/cm050316b

Polyphosphazenes that bear both methoxyethoxyethoxy and cinnamyl side groups were synthesized and evaluated for use as hydrogels incorporated into micrometer-scale biosensor arrays. Polymers with the general formula [NPR x R‘ y ] n where R = OCH2CH2OCH2CH2OCH3 and R‘ = OCHCHCH2Ph (x = y = 1; x = 2, y = 0) were synthesized. The polymers were cross-linked to form hydrogels by exposure to ultraviolet radiation (λ = 320−480 nm) in the presence of a photoinitiator. Hydrogel microstructures in the size range 50−500 μm were fabricated using standard photolithographic techniques. The resolution and dimensions of these microstructures were examined by optical microscopy, scanning electron microscopy, and profilometry. The resultant three-dimensional hydrogel microstructures were used to encapsulate enzymes for biosensor applications. The enzymatic activity of encapsulated horseradish peroxidase (HRP) was examined as a model system. The HRP catalyzed reaction between H2O2 and Amplex Red to produce a fluorescent product, resorufin, was confirmed by fluorescence microscopy.