Abstract: The increasing need for therapeutics and sensors drives the development of artificial receptors that recognize small peptides selectively. However, the many degrees of freedom of a simple di- or tripeptide make the rational design of a specific receptor for a given peptide to an extremely difficult task. As a result, while nature has evolved enzymes as well as small molecules (e.g. vancomycin) that bind peptides with high affinity and selectivity, so far only a few receptors have been designed rationally [1]. Thus, a more empirical approach that mimics the natural principles of random mutation and selection of the fittest is needed for the successful development of receptors binding small peptides selectively