Iron gall ink revisited: hierarchical formation of Fe(iii)–tannic acid coacervate particles in microdroplets for protein condensation

Abstract

Inspiration from the iron gall ink leads to the efficient formation of Fe(III)–tannic acid coacervate particles inside the phase-separated microdroplets that are derived from the aqueous PEG/dextran liquid–liquid phase separation system. This hierarchical self-assembly, in aid of the protein affinity of tannic acid, makes it possible to compartmentalize and condense proteins into a localized, compact space in the microdroplets.