Biomimetic diamond-like carbon coated titanium inhibits RANKL-dependent osteoclast differentiation in vitro

To examine the effects of titanium (Ti) coated with biomimetic diamond-like carbon (DLC) on osteoclast differentiation and bacterial biofilm formation, RAW264.7 cells and Porphyromonas gingivalis (P. g) were grown on Ti disks without DLC (control), or with DLC (DLC-treated). Real-time quantitative reverse transcriptase-polymerase chain reaction analysis showed that TRAP and cathepsin K mRNA levels in RAW264.7 cultured on DLC-treated Ti disks with soluble receptor activators for NF-κB ligand (sRANKL) were significantly lower than those of control Ti disks. Similarly, DLC-treated Ti decreased the expression of NFATcl protein in sRANKL-stimulated RAW264.7 cells. Futher, reduced P. g biofllm formation was observed on DLC-treated disks as compared with the biofilm on control Ti disks. These results, taken together, suggested that DLC altered osteoclast differentiation and biofllm formation of P.g, which could promise long-term success of implant therapy.