Ion-beam-modified surfaces as substrates for hydroxyapatite growth induced by laser-liquid-solid interaction

Abstract

In this study stainless steel, silicon and silica glass are used as representatives of metal, semiconductor and isolator with the purpose to create an experimental model for studying the formation of minerals like hydroxyapatite (HA, the bone and teeth mineral part) from aqueous solutions. The samples are Na+ implanted and consequently subjected to thermal treatment in air at 873 K. Implantation with Na+ is known to lead to formation of hydroxylated surface, i.e. formation of metal- or Si-OH- groups upon immersion in a liquid, simulating the human blood plasma (simulated body fluid, SBF). The negatively charged hydroxylated surfaces induce HA formation in SBF. The samples are immersed in SBF, irradiated through the solution with a scanning laser beam (CuBr pulsed laser equipped with a scanning system) and subsequently soaked in the solution at 37°C for a shorter time, comparing to the traditional methods for HA growing. The grown HA layers are investigated by Fourier Transform Infrared (FTIR) and Raman Spectroscopies, X-ray Diffraction (XRD), Light Microscopy (LM), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray (EDX) Spectroscopy to evaluate the effect of the surface modification by the thermal treatment following the ion implantation, as well as the effect of the laser irradiation on the process of HA formation.