A NEXAFS and XPS study of the adsorption of self-assembling peptides on TiO2: the influence of the side chains

Peptides consisting of an alternation of hydrophobic and hydrophilic (positively and negatively charged) amino acids can generate extended ordered structures by self-assembling (SA) from aqueous solutions. In this paperwe present XPS, near-edge X-ray absorption fine structure (NEXAFS) and Fourier transform infrared (FTIR) investigations on a series of SA peptides with the aim of determining the effect of side-chain length on molecular arrangement and orientation. Peptides were immobilised on the surface of titanium, a well-known biocompatible material, or deposited as thick films on inert gold surfaces. FTIR analysis yields information on the backbone conformation. XPS spectroscopy was used to investigate the peptide adsorption on the TiO2 surface