Nanoscale PDA disassembly in ionic liquids: structure-property relationships underpinning redox tuning

Nanoscale disassembly of mussel-inspired polydopamine (PDA) in ionic liquids (ILs) was recently shown to induce an electron paramagnetic resonance (EPR)-detectable reorganization of free radical centers in the resulting nanoparticles (NPs) in an IL-controlled manner. Herein, we report electrical impedance spectroscopy (EIS) data showing that PDA NPs produced by suspending samples obtained in Tris and bicarbonate buffer (PDA-T and PDA-C) in different ILs display different redox activity as a result of structural control combined with IL-surface interactions. In particular, susceptibility to oxidation was found to correlate closely with the spin density in an ion pair-tunable fashion in ILs. Structural control over free radical properties and redox behavior of PDA NPs in ILs opens novel perspectives for the rational design of functional nanovectors of possible interest for drug delivery and theranostic applications.