Photochemical micropatterning of carbohydrates on a surface.
In this report, we demonstrate a versatile method for the immobilization and patterning of unmodified carbohydrates onto glass substrates. The method employs a novel self-assembled monolayer to present photoactive phthalimide chromophores at the air-monolayer interface. Upon exposure to UV radiation, the phthalimide end-groups graft to surface-adsorbed carbohydrates, presumably by a hydrogen abstraction mechanism followed by radical recombination to form a covalent bond. Immobilized carbohydrate thin films are evidenced by fluorescence, ellipsometry and contact-angle measurements. Surface micropatterns of mono-, oligo-, and polysaccharides are generated by exposure through a contact photomask and are visualized by condensing water onto the surface. The efficiency of covalent coupling is dependent on the thermodynamic state of the surface. The amount of surface-grafted carbohydrate is enhanced when carbohydrate surface interactions are increased by the incorporation of amine-terminated molecules into the monolayer. Glass substrates modified with mixed monolayers of this nature are used to construct carbohydrate microarrays by spotting the carbohydrates with a robot and subsequently illuminating them with UV light to covalently link the carbohydrates. Surface-immobilized polysaccharides display well-defined antigenic determinants for antibody recognition. We demonstrate, therefore, that this novel technology combines the ability to create carbohydrate microarrays using the current state-of-the-art technology of robotic microspotting and the ability to control the shape of immobilized carbohydrate patterns with a spatial resolution defined by the UV wavelength and a shape defined by a photomask.
Carroll
Gregory T
GT
Department of Chemistry, Columbia University, 3000 Broadway, MC 3157, 10027, New York, New York, USA.
Wang
Denong
D
Turro
Nicholas J
NJ
Koberstein
Jeffrey T
JT
D002241:Carbohydrates / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008853:Microscopy; D010777:Photochemistry; D016339:Spectrometry, Mass, Fast Atom Bombardment; D013056:Spectrophotometry, Ultraviolet; D013499:Surface Properties
D002241:Carbohydrates