(53c) Predictive Binary Self-Assembly of Solid Binding Peptides at Graphite Interfaces for Complex Biomolecular Patterning

Control over the self-assembled hierarchical structure of functional biomolecules at solid electrode interfaces is essential for the fabrication of micron-scale bio-nanodevices. Promising candidates are solid-binding peptides selected for specific inorganic solids by directed evolution techniques. Many of these selected peptides have been shown to spontaneously form long-range ordered assemblies at two-dimensional solid surfaces, display functional molecules, and modify the substrate’s electronic properties. Advanced bio-nanotechnologies, such as multi-enzymatic bioreactors, will require multiple, independently tunable peptide functionalizations to tailor interfacial molecular density and structure. However, our understanding of miscibility and co-assembly of solid binding peptides at interfaces is lacking. Here we present our atomic-force microscopy investigations on binary peptide co-assemblies at cleaved graphite surfaces exhibiting extraordinarily well behaved immiscible long-range ordered structures. Nucleation rates of the co-assembled system exceeded those of the constituent peptide systems and were tunable by blending ratio and total peptide concentration. The observed peptide immiscibility is attributed to peptide specific substrate orientation relationships. Collectively, these findings led to model predictions of the co-assembly structure of immiscible peptides based on two-dimensional nucleation parameters of the single peptide assemblies. Our findings facilitate the molecular scale engineering of structured bio-nano interfaces through a multi-species self-assembly process, and with it advance the fabrication of high-density patterning of biomolecules for biosensor and bioreactor technologies. The research was supported by NSF-DMREF program through the grant DMR-1629071, 1848911, and 1922020 as part of the Materials Genome Initiative.