Platinum-Binding Peptides: Binding Kinetics, Affinities, and Facet-Specific Conformational Adaptation

Platinum-binding peptides (PtBPs) identified via phage display have emerged as powerful molecular tools for the controlled synthesis and functionalization of nanostructured platinum surfaces. However, the molecular determinants governing their surface recognition, binding strength, and structural adaptability remain incompletely understood. Here, a comparative analysis of five PtBPs, three previously reported (TLTTLTN, SSFPQPN, TLHVSSY) and two newly identified by phage display (TGELSQK, LLVTSVT), using quartz crystal microbalance with dissipation monitoring (QCM-D) and synchrotron radiation circular dichroism (SRCD) spectroscopy, is presented. Adsorption kinetics and binding affinities determined by QCM-D reveal sequence-specific differences in association and dissociation rates, which correlate with the viscoelastic properties of the adsorbed layers. SRCD spectra show that all peptides adopt predominantly disordered conformations in solution but exhibit facet-dependent spectral shifts upon adsorption onto platinum nanoparticles, consistent with conformational adaptation at the interface. The combined data highlight the importance of amino acid composition, kinetic binding parameters, and conformational flexibility in governing Pt–PtBP interactions. This integrated approach provides a deeper understanding of peptide–surface recognition and may support the rational design of sequence-defined biomolecules for use in catalysis, surface modification, and biomedical nanotechnology.