Peptide/TiO₂ Surface Interaction:  A Theoretical and Experimental Study on the Structure of Adsorbed ALA-GLU and ALA-LYS

Abstract

The adsorption on the TiO(2) surface of two dipeptides AE (L-alanine-L-glutamic acid) and AK (L-alanine-L-lysine), that are "building blocks" of the more complex oligopeptide EAK16, has been investigated both theoretically and experimentally. Classical molecular dynamics simulations have been used to study the adsorption of H-Ala-Glu-NH(2) and H-Ala-Lys-NH(2) dipeptides onto a rutile TiO(2) (110) surface in water solution. Several peptide conformers have been considered simultaneously upon the surface. The most probable contact points between the molecules and the surface have been identified. Carbonyl oxygens as well as nitrogen atoms are possible Ti coordination points. Local effects are responsible for adsorption and desorption events. Self-interaction effects can induce molecular reorientations giving less strongly adsorbed species. The chemical structure and composition of thin films of the two dipeptides AE and AK on TiO(2) were investigated by XPS (X-ray photoelectron spectroscopy) measurements at both O and N K-edges. Theoretical ab initio calculations (DeltaSCF) were also performed to simulate the spectra, allowing for a direct comparison between experiment and theory.

Deposition temperature dependence of titanium oxide thin films grown by remote‐plasma atomic layer deposition

“…The O 1s main peak at 530.2 eV was assigned to oxygen bound to Ti 4þ ions. The shoulder located at 531.77 eV can be attributed to hydroxyl (OH) species present in or on the TiO 2 film [25,26]. The difference in the binding energies of the hydroxyl species and O-Ti bonds was 1.57 eV, close to the reported literature difference of 1.5-1.9 eV [27][28][29][30].…”

Interactions between oligopeptides and oxidised titanium surfaces detected by vibrational spectroscopy

“…[2] These short peptides are easy to be designed and synthesised, biodegradable and highly biocompatible (do not induce any measurable immune response or tissue inflammation) and support mammalian cell attachment. [3] They have been used as matrices in tissue engineering (for neurite growth, synapsis formation, scaffolds for cartilage tissue repair and injectable nanofibres to create intramyocardial micro-environments for endothelial cells) [4] and in drug delivery systems. [5] These alternating oligopeptides have a preferential β-sheet structure and are resistant to proteolytic cleavage (by trypsin, chimotrypsin, papain, pronase and protease K at 100 µg/ml) [6] and may self-assemble to form an insoluble macroscopic membrane or fibrillar assemblies similar to those exhibited by β-amyloid.…”

Modeling and simulation of protein–surface interactions: achievements and challenges

“…Due to their good mechanical stability, catalytic properties and biocompatibility (Andreescu et al 2012), metal oxides and minerals are used in a wide range of applications that include fabrication of biomaterials (Whaley et al 2000), cellular delivery of drugs and biomolecules (Kievit & Zhang, 2011;Xu et al 2006), tissue engineering (Shin et al 2003) and proteomics (Sugiyama et al 2007). Computational studies to investigate the interactions of oxide and mineral surfaces with proteins or peptides have mostly been carried out for different forms of titanium dioxide, such as rutile and anatase (Carravetta et al 2009;Kang et al 2010;Köppen et al 2008;Monti, 2007;Monti et al 2008;Sun et al 2014a;Wu et al 2013), silicon dioxides (Chen et al 2009a;Nonella & Seeger, 2008;Patwardhan et al 2012;Rimola et al 2009;Tosaka et al 2010), calcite (Wierzbicki et al 1994) and mica (Kang et al 2013).…”