Surface Modification of Bioactive Glasses by Femtosecond and CO2 Lasers

This study explores the potential of laser surface modification (LSM) to enhance the biological properties of melt-derived bioactive glasses, specifically 45S5 and ICIE16, which are key in medical implants due to their bone-regenerating capabilities. Despite their bioactivity, these materials have limitations in cellular adhesion due to their smooth surfaces. LSM enables the creation of precise surface patterns that could improve interactions with biological environments. This study involved surface texturing bioactive glass (BG) samples using CO2 and femtosecond (fs) laser systems, modifying the laser average power, scanning speed, line spacing, and number of passes. Characterization methods included optical and stereoscopic microscopy, profilometry, and solubility tests in Tris-HCl buffer to evaluate surface roughness evolution, morphology, and bioactive behavior. The findings demonstrated significant modifications in surface properties post-texturing. The CO2 laser-treated surfaces preserve the increased roughness values after 75 days of immersion in Tris-HCl buffer for both 45S5 and ICIE16 melt-quenched bioactive glasses, showing a potential long-term osteoconductivity enhancement. On the contrary, the femtosecond laser-treated surfaces revealed a preferential apatite precipitation ability at the pattern grooves. Femtosecond laser modification stands as a suitable technique to provide preferential osteoconductivity characteristics when conducted on the surface of bioactive glass with moderate reactivity, such as ICIE16 bioactive glass.