Response of Saos-2 osteoblast-like cells to laser surface texturing, sandblasting and hydroxyapatite coating on CoCrMo alloy surfaces.

Cobalt chrome alloys are commonly used in orthopaedic implants where high stiffness and wear resistance are required. This study proposes Laser Surface Texturing (LST) as a cost-effective mean for producing bioinspired surface textures in order to improve the performance of CoCrMo orthopaedic implants. Cobalt-chrome alloy disks were modified using three different LST strategies: i) micro-scale texturing using a nanosecond laser source; (ii) micro-scale texturing with an ultrashort laser source and (iii) bioinspired sub-micron scale texturing with an ultrashort laser source. The modified disks were characterized and compared to blasted, hydroxyapatite coated and polished surface finishes. Saos-2 osteoblast-like cells were seeded on the different surfaces and their proliferation and morphology was assessed. The laser modification increases the surface energy of the CoCrMo alloy disks when compared to their untreated counterparts. The bioinspired sub-micron textured surfaces exhibited the highest cell metabolic activity on day 7 of the MTT assay.