Interactions between single-walled carbon nanotubes (SWNT) and peptides are investigated. An existing polarizable force field, using distributed multipoles up to quadrupoles for the electrostatics, is modified to include a description of the non-bonded interactions between a SWNT and peptides. Adsorption energies and structures calculated with this potential are compared with data from electronic structure theory. Simulations of binding and non-binding peptide aptamers, as identified from experiment, are shown to agree with current experimental observations.