An in situ atomic force microscopy (AFM) investigation of tropoelastin-like peptide assembly at ordered interfaces

The adsorption of molecules at a surface is a complex process governed in part by the local chemical and physical structure of both the substrate and the adsorbate. For biomolecules, this process is further complicated by their flexibility and structural hierarchy. We have used variable temperature in situ atomic force microscopy to study the self-assembly of recombinant human elastin peptides EP I, EP II and EP IV. Whereas on hydrophilic mica, the EP peptides formed unstable amorphous aggregates, on hydrophobic highly ordered pyrolytic graphite (HOPG), the EP peptides bound stably to the substrate, forming an ordered multi-layer structure comprising a supporting thin film and epitaxially oriented molecular fibrils. Remarkably, in agreement with the known solution coacervation characteristics of the EP peptides, these surface-driven assembly processes were facilitated at higher temperatures. Controlling these processes may provide an attractive means of designing novel peptide nanostructures.