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Monte Carlo simulations are performed to study adsorption and desorption of coarse-grained peptide chains on generic gold and palladium surfaces in the presence of solvent. The atomistic structural details are ignored within the amino acid residues; however, their specificity and hydrophobicity are incorporated via an interaction matrix guided by atomistic simulation. Adsorption probabilities of the peptides A3, Flg, Pd2, Pd4, Gly10, Pro10 on gold and palladium surfaces are studied via analysis of the mobility of each residue, the interaction energy with the surface, profiles of the proximity to the surface, the radius of gyration, and comparisons to homopolymers. In contrast to the desorption of Gly10 and Pro10 (with faster global dynamics), peptides Pd2, Pd4, Flg, and A3 exhibit various degrees of adsorption on gold and palladium surfaces (with relatively slower dynamics). Adsorption on both gold and palladium occurs through aromatic anchoring residues Tyr2 and Phe12 in A3, Tyr2 in Flg, Phe2, His10 and His12 in Pd2, and His6 and His11 in Pd4. A lower (more negative) surface-interaction energy of these residues and lower mobility on palladium lead us to conclude that they are slightly more likely to be adsorbed on palladium surfaces than on gold.

Self-assembly and function of biologically modified metal nanostructures depend on surface-selective adsorption; however, the influence of the shape of metal surfaces on peptide adsorption mechanisms has been poorly understood. The adsorption of single peptide molecules in aqueous solution (Tyr(12) , Ser(12) , A3, Flg-Na(3) ) is investigated on even {111} surfaces, stepped surfaces, and a 2 nm cuboctahedral nanoparticle of gold using molecular dynamics simulation with the CHARMM-METAL force field. Strong and selective adsorption is found on even surfaces and the inner edges of stepped surfaces (-20 to -60 kcal/mol peptide) in contrast to weaker and less selective adsorption on small nanoparticles (-15 to -25 kcal/mol peptide). Binding and selectivity appear to be controlled by the size of surface features and the extent of co-ordination of epitaxial sites by polarizable atoms (N, O, C) along the peptide chain. The adsorption energy of a single peptide equals a fraction of the sum of the adsorption energies of individual amino acids that is characteristic of surface shape, epitaxial pattern, and conformation constraints (often β-strand and random coil). The proposed adsorption mechanism is supported and critically evaluated by earlier sequence data from phage display, dissociation constants of small proteins as a function of nanoparticle size, and observed shapes of peptide-stabilized nanoparticles. Understanding the interaction of single peptides with shaped metal surfaces is a key step towards control over self-organization of multiple peptides on shaped metal surfaces and the assembly of superstructures from nanostructures.

Monte Carlo simulations have been employed to identify the morphologies of symmetrical AB diblock copolymer melts under the confinement of nanocylindrical tubes. The effects of (i) the incommensurability between the diameter of the tube and the lamellae period in the bulk and (ii) the preference of the tube surface for one of the segments have been investigated. Lamellae normal to the tube axis and circular lamellae have been observed under the conditions investigated, in agreement with experiment and density functional calculations. Furthermore, porous lamellar (mesh) morphologies, lamellae parallel to the tube axis as well as single and double helixes have been identified.