| Abstract
| - We describe a method to pattern proteins onto a photolabile “caged” biotin-derivatized self-assembledmonolayer (SAM) on gold, which we term light-activated affinity micropatterning of proteins (LAMP).LAMP is a multistep patterning process with considerable flexibility in its implementation. First, a reactiveSAM on gold is formed from a mixture of 11-mercaptoundecanol and 16-mercaptohexadecanoic acid. Next,the carboxylic acid end groups in the SAM are coupled to methyl α-nitropiperonyloxycarbonyl biotinsuccinimidyl ester (caged biotin ester) through a diamine linker. The caged biotin is then deprotected inregions irradiated by masked UV light, and subsequent incubation with streptavidin results in selectivebinding of streptavidin to the irradiated regions. Micropatterning of various proteins has been demonstratedwith a spatial resolution of ∼6 μm by confocal microscopic imaging of fluorophore-labeled proteins, anda contrast ratio of ∼4:1 was determined by direct ellipsometric imaging of streptavidin. Immobilizationof biotinylated antibodies on the streptavidin pattern indicates that LAMP can enable spatially resolvedmicropatterning of different biomolecules by repeated cycles of spatially defined photodeprotection ofbiotin, streptavidin incubation, followed by immobilization of the biotinylated moiety of interest.
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