Interaction of gold and platinum nanoparticles with L-tyrosine in aqueous solution: Conformational and dynamic changes

This study investigates the effects of gold and platinum nanoparticles (NPs) on the structural and dynamic properties of L-tyrosine in aqueous solution. Using a combination of spectrophotometry, 1H NMR, DOSY, and NOESY techniques, we examined the interactions between L-tyrosine and metal NPs, focusing on their influence on molecular conformation and hydrodynamic behaviour. Spectrophotometric analysis revealed significant shifts and broadening in the electronic absorption spectrum of L-tyrosine upon the addition of gold and platinum NPs, with platinum NPs inducing more substantial spectral changes.NMR experiments demonstrated that the interaction of L-tyrosine with NPs caused distinct conformational changes: platinum NPs stretched the tyrosine molecule, while gold NPs caused molecular compression. DOSY analysis further corroborated these findings, showing a reduction in the diffusion coefficient for L-tyrosine in the presence of platinum NPs, correlating with an increased hydrodynamic radius. Conversely, gold NPs reduced the hydrodynamic radius and increased the diffusion coefficient.These results provide insights into the molecular interactions between amino acids and metal NPs, which are crucial for designing biocompatible nanomaterials for biomedical applications. The study underscores the contrasting effects of gold and platinum NPs on the structural integrity and mobility of L-tyrosine, highlighting their potential in molecular nanoengineering for drug delivery and cancer treatment.