Biocompatible Materials Based on Self-Assembling Peptides on Ti25Nb10Zr Alloy: Molecular Structure and Organization Investigated by Synchrotron Radiation Induced Techniques.

Valeria Secchi,Mariana Braic,Jaroslava Nováková,Tomáš Skála,Marta Santi,Annj Zamuner,Alina Vladescu,Chiara Battocchio,Stefano Franchi,Monica Dettin,Giovanna Iucci

doi:10.3390/nano8030148

Abstract

In this work, we applied advanced Synchrotron Radiation (SR) induced techniques to the study of the chemisorption of the Self Assembling Peptide EAbuK16, i.e., H-Abu-Glu-Abu-Glu-Abu-Lys-Abu-Lys-Abu-Glu-Abu-Glu-Abu-Lys-Abu-Lys-NH2 that is able to spontaneously aggregate in anti-parallel β-sheet conformation, onto annealed Ti25Nb10Zr alloy surfaces. This synthetic amphiphilic oligopeptide is a good candidate to mimic extracellular matrix for bone prosthesis, since its β-sheets stack onto each other in a multilayer oriented nanostructure with internal pores of 5–200 nm size. To prepare the biomimetic material, Ti25Nb10Zr discs were treated with aqueous solutions of EAbuK16 at different pH values. Here we present the results achieved by performing SR-induced X-ray Photoelectron Spectroscopy (SR-XPS), angle-dependent Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy, FESEM and AFM imaging on Ti25Nb10Zr discs after incubation with self-assembling peptide solution at five different pH values, selected deliberately to investigate the best conditions for peptide immobilization.

Highlights

The increased interest in titanium (Ti) and its alloys for dental implants and prosthesis application derives from their exceptional mechanical properties, corrosion resistance and biocompatibility [1,2]
A gentle surgical technique combined with sufficient healing time has long been considered the key to osseo-integration, and excellent long-term clinical outcome for dental implant validates the results of pre-clinical experimental studies
We present the characterization, carried out by synchrotron radiation-induced X-ray Photoemission Spectroscopy (SR-X-ray Photoelectron Spectroscopy (XPS)), angle-dependent Near Edge X-rays Absorption Fine Structure (NEXAFS) spectroscopy, Field Emission Scanning Electron Microscopy (FE-scanning electron microscopy (SEM)) and Atomic Force Microscopy (AFM) investigations of Ti25Nb10Zr alloy surfaces functionalized by the self-assembling peptides (SAPs) EAbuK16 (Abu stands for α-aminobutyric acid), i.e., H-Abu-Glu-Abu-Glu-AbuLys-Abu-Lys-Abu-Glu-Abu-Glu-Abu-Lys-Abu-Lys-NH2

Summary

Introduction

The increased interest in titanium (Ti) and its alloys for dental implants and prosthesis application derives from their exceptional mechanical properties, corrosion resistance and biocompatibility [1,2]. The in vitro and in vivo tests performed on Ti6Al4V alloy showed that this alloy has a toxic effect resulting from released V and Al and that its elastic modulus is very distant from the bone value [10,11,12,13,14,15,16], restricting its use in biomaterial applications On this basis, a lot of experiments have been carried out to develop a novel Ti based alloy consisting only of biocompatible elements, which could replace the Ti6Al4V alloy in clinical practice [9,17,18,19]. It is worth mentioning that there are a lot of other proposed alloys in the literature, such as Ti-Nb-Zr-Ta [20,21,22,23,24], Ti-Mo-Zr-Fe [25,26], Ti-Al-Zr [27], Ti-Al-Fe [18], Ti-Nb-Fe [28,29], Ti-Nb-Zr-Sn [30] and Ti-Nb [31] systems, but no standards have been published

Methods

Results

Conclusion