Self-assembling behaviour of self-complementary oligopeptides on biocompatible substrates

Self-complementary amphiphilic oligopeptides, consisting of an alternation of hydrophobic and hydrophilic amino acids and of positively and negatively charged groups can generate extended ordered structures by self-assembling (SA) from aqueous solutions, and have been successfully tested as promising candidates for scaffolds in several fields of tissue engineering. In this paper we present a systematic XPS, NEXAFS and FTIR investigation carried out on a series of SA peptides consisting of different selected sequences of 16 residues, with the aim of determining the effect of side chains length on molecular arrangement and orientation. Peptides were immobilized 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. The orientation of the peptide chains was studied by angular-dependent NEXAFS. The performed spectroscopical characterization leads to widely investigate the physical properties of biopolymers–peptide coatings.