Most clinical technologies for detecting protein biomarkers are antibody based. As an alternative approach, my research focuses on the development of protein-catalyzed capture agents (PCCs) – compounds that possess the affinities and specificities of antibodies, but also are highly stable on the shelf and in vivo. PCCs are selected for specific binding through synthetic combinatorial peptide library methodologies that make use of the target protein as the catalyst for assembling a multivalent ligand. We are exploiting the small size, low cost, and rapid synthesis of PCCs to monitor biomarkers to detect cancer and other serious diseases.