Osteogenesis of human mesenchymal stem cells on micro-patterned surfaces.

Osteogenic responses of human mesenchymal stromal cells (hMSCs) were compared on square-patterned, inverse square-patterned, and planar titanium, chromium, diamond-like carbon (DLC), and tantalum; hypothesis was that both the materials and patterns affect osteogenesis. Samples were produced using photolithography and physical vapor deposition. Early-marker alkaline phosphatase (ALP) and mid-markers, small body size and mothers against decapentaplegic-related protein-1 (SMAD1), runt-related transcription factor-2 (RUNX2), and osteopontin were studied using quantitative real-time polymerase chain reaction. ALP and hydroxyapatite, were colorimetrically studied. ALP reached highest values on both patterned titanium samples, but mid-markers disclosed that it was already lagging behind planar and inverse patterned tantalum. Hydroxyapatite formation disclosed that osteo-induced hMSCs passed all the differentiation stages (except on planar chromium). Presence of hydroxyapatite disclosed that both types of patterning promoted (p < 0.001) osteogenesis compared to planar samples. Results suggest that the osseocompatibility/integration of implants could be improved by changing the monotonous and featureless implant-host interface into micro-patterned interface to provide physical differentiation cues.