  An amphiphilic nature of the surfactant-like peptides is responsible for
their propensity to aggregate at the nanoscale. These peptides can be readily
used for a non-covalent functionalization of nanoparticles and macromolecules.
This work reports an observation of supramolecular ensembles consisting of
ultrashort carbon nanotubes (USCNTs), graphene (GR) and A9K polypeptide formed
by lysine and arginine. Potential of mean force (PMF) is used as a major
descriptor of the CNT-A9K and GR-A9K binding process, supplementing structural
data. The phase space sampling is performed by multiple equilibrium molecular
dynamics simulations with position restraints, where applicable. Binding in all
cases was found to be thermodynamically favorable. Encapsulation in the (10,10)
USCNT is particularly favorable. Curvature of external surface does not favor
binding. Thus, binding of A9K at GR is stronger than its binding at the outer
sidewall of USCNTs. Overall, the presented results favor non-covalent
functionalization of nanoscale carbons that are considered interesting in the
fields of biomaterials, biosensors, biomedical devices, and drug delivery.
