High-power laser surface structuring of bioactive glasses: Recent advances and perspectives

Introduction

Bioactive glasses are a type of biomaterial widely used when high osteoconductive or osteosynthesis capabilities are required. In recent years, research on bioactive glasses has been partially directed towards obtaining more stable compositions with increased network connectivity. Thus, it is possible to use this biomaterial in diverse applications with high surface/volume ratios, such as scaffolds, in which the most reactive bioactive glasses experience excessively rapid dissolution. The micro-structuring of the surface of these biomaterials is a research niche that has been scarcely explored, mainly because the osteoconductivity mechanism that occurs during the interaction with biological fluids is associated with the dissolution of the glass surface layer. However, it has recently been shown that surface modification by laser can produce permanent long-term surface changes.

Methods

For this work, recent reports in the field of laser surface modification of bioactive glass have been critically studied and analysed. In addition, laboratory experiments have been carried out on the structuring of the surface of glasses with different network connectivities. The in vitro behaviour when in contact with simulated physiological fluid has been characterised.

Results and conclusions

In this work, the latest advances in laser surface modification of bioactive glasses are presented, discussing the different types of lasers used and the radiation–matter interaction phenomena, particularly in terms of surface energy density and interaction times. Furthermore, the properties of the micro-structured surfaces are presented as a function of the parameters of the laser surface modification process and their evolution when they are subjected to contact with simulated physiological fluids.

The in vitro behavior of the laser-modified bioactive glass surface demonstrates that, by selecting the appropriate laser radiation and the appropriate process conditions, it is possible to produce a selective change in the osteoconductivity process.