Adsorption Behaviors of Typical Proteins on BP, GR, and C₂N Surfaces

The biotoxicity of nanomaterials is very important for the application of nanomaterials in biomedical systems. In this study, proteins with varying secondary structures (α-helices, β-sheets, and mixed α/β structures) were employed to investigate the biological properties of three representative two-dimensional (2D) nanomaterials; these nanomaterials consisted of black phosphorus (BP), graphene (GR), and nitrogenized graphene (C₂N) and were studied using molecular dynamics simulations. The results showed that the α-helix motif underwent a slight structural change on the BP surface and little structural change on the C₂N surface. In contrast, the structure of the β-sheet motif remained fairly intact on both the BP and C₂N surfaces. The α-helix and β-sheet motifs were able to freely migrate on the BP surface, but they were anchored to the C₂N surface. In contrast to BP and C₂N, GR severely disrupted the structures of the α-helix and β-sheet motifs. BBA protein with mixed α/β structures adsorbed on the BP and C₂N surfaces and exhibited biological behaviors that were consistent with those of the α-helix and β-sheet motifs. In summary, C₂N may possess better biocompatibility than BP and GR and is expected to have applications in the biomedical field. This study not only comprehensively evaluated the biological characteristics of nanomaterials but also provided a theoretical strategy to explore and distinguish the surface characteristics of nanomaterials.