Combinatorial Libraries and Molecular Recognition - Match or Mismatch?

During the past decade combinatorial libraries have emerged as a major tool for drug discovery and drug development. Especially one-bead-one-structure libraries can be a powerful means for the discovery of ligands to natural and synthetic hosts and vice versa. Encoded combinatorial libraries have been used to disclose ligands for well-designed macrocyclic host molecules and to elucidate their specificities for peptide sequences. These studies led via receptors with more flexibility to simple host molecules without elaborate design that are accessible to combinatorial synthesis. These findings opened a realm of possibilities and applications. An intriguing one is the development of chemical sensors for analytes that are otherwise hard or only unspecifically detected. Furthermore, such libraries and the techniques that were developed to handle them have been used to find new catalysts and enzyme mimics.