Reduction of resazurin to resorufin catalyzed by gold nanoparticles: dramatic reaction acceleration by laser or LED plasmon excitation

Abstract

Plasmon excitation (532 nm) of gold nanoparticles in the presence of resazurin and hydroxylamine leads to their photocatalytic reduction to resorufin with great efficiency. In the case of laser excitation under laser-drop conditions the process is essentially complete following an ∼8 ns laser pulse at 532 nm. Excitation with LED sources at ∼530 nm proves to be a simple and cost efficient way to promote plasmon-assisted reactions. We propose that the catalytic reaction is thermally activated by the gold nanoparticle and takes advantage of the high temperatures achievable under plasmon excitation.