Titanium coated with gold nanoparticles: a multifaceted investigation through electrochemical, spectroscopic, and biological approaches
Dominika Święch, Gaetano Palumbo, Piotr Jabłoński, Marta Gajewska, Anna Gołda, Joanna Kozieł, B. Mingo, Natalia Piergies, Dirk Engelberg
Abstract
• AuNPs improve titanium’s corrosion resistance and antibacterial activity. • SERS, SEIRA, AFM − SEIRA reveal Cys adsorption mechanism on Ti − AuNPs surface. • Au–S bonding and NH 3 + interactions maintain cysteine adsorption on the surface. • Ti − AuNPs present a multifunctional surface for biomedical applications. Titanium functionalized with an ultrathin layer of gold nanoparticles (Ti − AuNPs) provides a multifunctional surface with enhanced corrosion resistance, antibacterial activity, and biomolecular interaction potential. In this study, Ti − AuNPs were prepared and characterized using electrochemical, microscopic, and spectroscopic techniques, with a focus on cysteine (Cys) adsorption as a model thiol-containing biomolecule. Electron microscopy investigations confirmed uniform deposition of AuNPs on the passive TiO 2 layer, while electrochemical analysis showed that the AuNP coating improved corrosion resistance and preserved substrate integrity. Antibacterial testing revealed reduced bacterial colonization on Ti − AuNPs surfaces. Spectroscopic analysis indicated strong Cys binding via Au–S bonds, supported by electrostatic and hydrogen bonding interactions involving carboxylate (COO − ) and protonated amino (NH 3 + ) groups. Atomic Force Microscopy (AFM) combined with infrared spectroscopy allows characterization of the spatial orientation of Cys after its adsorption onto Ti − AuNPs, which is difficult to achieve using other methods. These findings demonstrate the potential of the Ti − AuNPs surface for advanced biomedical applications.