Peptide sequences are known to recognize and bind different nanomaterial surfaces, which has resulted in the screening and identification of hundreds of peptides with the ability to bind to a wide range of metallic, metal oxide, mineral, and polymer substrates. These biomolecules are able to bind to materials with relatively high affinity, resulting in the generation of a complex biointerface between the biotic and abiotic components. While the number of material-binding sequences is large, at present, quantitative materials-binding characterization of these peptides has been accomplished only for a relatively small number of sequences. Moreover, it is currently very challenging to determine the molecular-level structure(s) of these peptides in the materials adsorbed state. Despite this lack of data related to the structure and function of this remarkable biointerface, several of these peptide sequences have found extensive use in creating functional nanostructured materials for assembly, catalysis, energy, and medicine, all of which are dependent on the structure of the individual peptides and collective biointerface at the material surface. In this Review, we provide a comprehensive overview of these applications and illustrate how the versatility of this peptide-mediated approach for the growth, organization, and activation of nanomaterials could be more widely expanded via the elucidation of biointerfacial structure/property relationships. Future directions and grand challenges to realize these goals are highlighted for both experimental characterization and molecular-simulation strategies.

Biomimetic nanotechnologies that use peptides to guide the growth and assembly of nanostructures offer new avenues for the creation of functional nanomaterials and manipulation of their physicochemical properties. However, the impacts of peptide sequence and binding motif upon the surface characteristics and physicochemical properties of nanoparticles remain poorly understood. The configurations of the biomolecules are expected to be extremely important for directing the synthesis and achieving desired material functionality, and these binding motifs will vary with the peptide sequence. Here, we have prepared a series of Au nanoparticles capped with a variety of materials-directing peptides with known affinity for metal surfaces. These nanomaterials were characterized by UV-vis and circular dichroism spectroscopies, transmission electron microscopy, and ζ-potential measurement. Then their catalytic activity for 4-nitrophenol reduction was analyzed. The results indicate that substantially different Au–peptide interfaces are generated using different peptide sequences, even when these sequences have similar binding affinity. This is consistent with recent work showing that Au–peptide binding affinity can have varying entropic and enthalpic contributions, with enthalpically- and entropically-driven binders exhibiting quite different ensembles of configurations on the Au surface. The catalytic activity, as reflected by the measured activation energy, did not correlate with the particle size or with the binding affinity of the peptides, suggesting that the reactivity of these materials is governed by the more subtle details of the conformation of the bound peptide and on the nanoparticle surface reconstruction as dictated by the peptide structure. Such variations in both nanoparticle surface reconstruction and peptide configuration could potentially be used to program specific functionality into the peptide-capped nanomaterials.