Tuning the Unidirectional Electron Transfer at Interfaces with Multilayered Redox-active Supramolecular Bionanoassemblies

In this work, we present a new strategy to construct redox-active molecular platforms to be used as molecular rectifiers with tunable and amplifiable electronic readout. The approach is based on using ligand-receptor biological interactions to bioconjugate electroactive bio-inorganic building blocks onto metal electrodes. The stability of the self-assembled interfacial architecture is provided by multivalent macromolecular ligands that act as scaffolds for building-up the multilayered structures. The ability of these electroactive supramolecular architectures to generate a unidirectional current flow and tune the corresponding electronic readout was demonstrated by mediating and rectifying the electron transfer between redox donors in solution and the Au electrode. The redox centers incorporated into the assembled architecture in a topologically controlled manner are responsible for tuning the amplification of the rectified electronic readout, thus behaving as a tunable bio-supramolecular diode. Our experimental results obtained with these redox-active bio-supramolecular architectures illustrate the versatility of molecular recognition-directed assembly in combination with hybrid bio-inorganic building blocks to construct highly functional interfacial architectures.