Beyond Primary Nucleation: Molecular Basis of Peptide Crystal Secondary Nucleation at Soft Interface

ABSTRACT

The formation of peptide 2D crystals with well‐organized molecular arrays by primary nucleation mechanism have provided an efficient way to incorporate biofunctions into the underlying single layer graphene and MoS ₂ , leading to broad applications for biosensing, biomedicine and bioelectronics. Further realizing a high‐level architecture of peptide 3D crystals coupling with the underlying nanomaterials would expand its applications for the next‐generation bionanodevices, while facing a big challenge. A layer‐by‐layer stacking of 3D peptide assemblies through secondary nucleation (SN) mechanism at soft interface provides an available strategy while its molecular basis has been rarely explored. We utilized time‐resolved 3‐dimensional atomic force microscopy (3D‐AFM) to directly observe SN and growth mechanism of stacked peptide 3D crystals on highly oriented pyrolytic graphite (HOPG). Moreover, the formation details of peptide 3D crystals including nucleation sites, growth dynamics, molecular‐resolution nanostructures, phase transitions, and cross‐seeding growth were discovered. Such non‐traditional methodology in engineering peptide 3D crystals would bring new prospects for nanoscience and nanotechnology.