Bioactive nanofibers present a promising synthetic niche for in vivo applications due to their morphological and functional resemblance to the extracellular matrix. Potentially interesting nanofibers are constructed from the hard-segment regimes in well-defined thermoplastic elastomers (TPEs). The supramolecular interactions between these hard segments cause physical crosslinking by the formation of nanofibers and provide excellent mechanical properties. Here, we make use of a new class of biocompatible supramolecular TPEs, in which both the formation of the main chain and the hard block is based on multiple hydrogen-bonding interactions. A self-assembly process is explored to arrive at well-defined peptide-modified nanofibers embedded in a biocompatible soft matrix. Crucial for the success in the synthetic design is the use of an exact match between the molecular recognition units of the peptide and the supramolecular unit that takes care of forming the supramolecular nanofibers of the TPE. Evidence for the strong anchoring of the modified peptides in the hard-segment nanofibers of the supramolecular TPE is provided by simple extraction experiments. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49:1764-1771, 2011