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Attach, Remove, or Replace: Reversible Surface Functionalization Using Thiol–Quinone Methide Photoclick Chemistry
journal contribution
posted on 2012-05-23, 00:00 authored by Selvanathan Arumugam, Vladimir V. PopikA very facile reaction between photochemically generated o-naphthoquinone methides (oNQMs) and thiols
is employed for reversible light-directed surface derivatization and
patterning. A thiol-functionalized glass slide is covered with an
aqueous solution of a substrate conjugated to 3-(hydroxymethyl)-2-naphthol
(NQMP). Subsequent irradiation via shadow mask results in the efficient
conversion of NQMP into reactive oNQM species in
the exposed areas. The latter react with thiol groups on the surface,
producing thioether links between the substrate and the surface. Unreacted oNQM groups are rapidly hydrated to regenerate NQMP. The
short lifetime of oNQM in aqueous solution prevents
its migration from the site of irradiation, thus allowing for the
spatial control of the surface derivatization. A two-step procedure
was employed for protein patterning: photobiotinylation of the surface
with an NQMP–biotin conjugate followed by staining with FITC–avidin.
The orthogonality of oNQM–thiol and azide
click chemistry allowed for the development of a sequential click
strategy, which might be useful for the immobilization of light-sensitive
compounds. The thioether linkage produced by the reaction of oNQM and a thiol is stable under ambient conditions but
can be cleaved by UV irradiation, regenerating the free thiol. This
feature allows for the removal or replacement of immobilized substrates.