Friday, 20 March, 2009
On the Mechanism of Trolox as Antiblinking and Antibleaching Reagent
T. Cordes, J. Vogelsang and P. Tinnefeld -
J. Am. Chem. Soc., 131 (14) (2009)
Recent advances in photobleaching and blinking prevention have aided the advancement of single-molecule and super-resolution fluorescence microscopy. However, a common mechanism of the action of antifading agents such as Trolox is still missing. In this communication we present evidence that Trolox acts in accordance with a mechanism that involves triplet quenching through electron transfer and subsequent recovery of the resulting radical ion by the complementary redox reaction. The required oxidant for this unifying mechanism based on a reducing and oxidizing system (ROXS) is formed via (photo-) reaction with molecular oxygen. We present evidence that this oxidized form is a quinone derivative of Trolox with strong oxidizing properties. These findings shed light on many contradicting results regarding the action of antifading agents and might lead to a common mechanistic understanding of photobleaching and its prevention. Finally, a recipe on the proper use of Trolox as an antifading agent is provided.