Controlled In-Cell Generation of Active Palladium(0) Species for Bioorthogonal Decaging

Owing to their bioorthogonality, transition metals have become very popular in the development of biocompatible bond-cleavage reactions. However, many approaches require design and synthesis of complex ligands or formulation of nanoparticles which often perform poorly in living cells. This work reports on a method for the generation of an active palladium species that triggers bond-cleaving reactions inside living cells. We utilized the water-soluble Na2PdCl4 as a simple source of Pd-II which can be intracellularly reduced by sodium ascorbate to the active Pd-0 species. Once generated, Pd-0 triggers the cleavage of allyl ether and carbamate caging groups leading to the release of biologically active molecules. These findings do not only expand the toolbox of available bioorthogonal dissociative reactions but also provide an additional strategy for controlling the reactivity of Pd species involved in Pd-mediated bioorthogonal reactions.

Automated summary

This study reports a method for generating an active palladium species inside living cells and triggering bond-cleavage reactions to release biologically active molecules. These findings not only expand the toolbox of available bioorthogonal dissociative reactions, but also provide an additional strategy for controlling Pd-mediated reactions.