Femtosecond laser as a tool to modify the interaction between bioceramic surface and cells

Written by Marie Lasgorceix, Belgian Ceramic Research Centre, Mons, Belgium

The bioactivity of synthetic bone implants is highly impacted by their surface properties. The aim of this work is to investigate the effect of micropatterned bioceramic surfaces on the cell behaviour.

Laser machining technology is employed to produce controlled regular micro-patterns on dense calcium phosphate surfaces. The choice of the source is directed towards a femtosecond pulsed laser, in order to limit the thermal impact of such a process and thus to avoid the unwanted phase transformations potentially induced by the temperature elevation. An accurate optimization of the process parameters (laser power, scanning speed, pulse frequency) allow to obtain perfectly controlled micropatterns with several complex designs and without any secondary phase. The effects of the process parameters on the patterning is investigated by microscopy (optical, confocal, scanning electron) and the phase identification is performed by XRD and Raman spectroscopy.

The influence of surface micro-patterning on cells behaviour is studied in vitro. In particular, an elongation of the cells shape is observed along linear grooves made by laser machining, whereas cells appear more spread on smooth surfaces, showing that linear patterning should promote cell migration.
This work show that this new technology seems to provide an interesting alternative to conventional ceramic surface treatments of calcium phosphates.

Financial support: “BEWARE” program (convention n°1510392) co-funded by Wallonia and European Union (FP7 – Marie Curie Actions) and JECS Trust Action "Frontiers of Research".

Left picture: Confocal micrograph - Alignment of MG63 osseous cells along the grooves made by femtosecond laser on calcium phosphate substrate
Right picture: SEM micrograph - Attachment of human bone marrow stromal cell on micropatterned calcium phosphate substrate