Morphological, ultrasonic mechanical and biological properties of hydroxyapatite layers deposited by pulsed laser deposition on alumina substrates

The development of biomaterials innovative compositions to be appropriate for hard tissue regeneration is vital and wished to improve the quality of life worldwide. In this work, using the pulsed laser deposition (PLD) technique, hydroxyapatite (HAP) was sputtered on a dense substrate of alumina at different times of exposure. The investigation of surface morphology indicated that grains of alumina were configured with dimensions of about 1.3-2.94 mu m, while high content of porosity was observed. Moreover, the data revealed a significant plunge of surface roughness, whereas the average roughness decreased from 53 nm to 29 nm, and the maximum roughness valley depth decreased from 281 to 248 nm, recorded for 5 to 20 min of exposure time. The mechanical properties were examined non-destructively using ultrasonic waves, and it was noticed that the microhardness changed significantly from 24.7 +/- 0.7 GPa to 27.2 +/- 0.8 GPa for the compositions compared to 0 and 20 min samples. The attachment behavior of human osteoblasts cell line towards the obtained scaffolds was examined in vitro and prove that cells were proliferated and spread to cover the scaffold surface. This elucidates that manipulation of an innovative scaffold design can be executed based on tailoring of bioactive material (HAP) depositions on an inert biomaterial (alumina) to combine both mechanical and bioactivity, with less degradation rate.