Evaluation of the degree of differentiation of human mesenchimal stem cells on different titanium superfaces: A pilot study

The aim of our study was to evaluate the properties of a laser-modified titanium surface, specifically the promotion of a faster differentiation of human Mesenchymal Stem Cells (hMSCs) into osteoblasts and a more stable connection between differentiated cells and titanium, compared to machined and sandblasted surfaces. Furthermore, we wanted to assess if the titanium alone could be a sufficient factor in the induction of the differentiation towards the osteogenic lineage. Materials and methods: we harvested stem cells from an individual (under his consensus) and cultivated them into dishes containing titanium disks presenting three different surfaces: machined (M), sand-blasted (S) and laser-modified (L). In the test group, cells were cultivated in an osteogenic medium, while in the control group, cells were seeded in a standard DMEM. Evaluations of the degree of differentiation were made with Alizarin coloration after 28, 38, 42, 49, 56 and 63 days from induction. Results: no signs of differentiation were evident in the control group, while in the test group there was a statistically significant differentiation, evident since the fourth week. Laser-modified and sand-blasted surfaces showed similar values, higher than the machined surface. Discussion: on the laser-modified surface the differentiation reached its peak on the sixth week, while on the seventh week for the other two surfaces. After the peak, the differentiation showed a slow decrease for the laser-modified surface and a rapid decrease for the other two. Conclusions: titanium alone can’t be considered enough to induce differentiation of human Mesenchymal Stem Cells into osteoblasts. Still, the laser-modified once induced a faster differentiation of stem cells and a more stable connection between osteoblasts and titanium.