53. Biomimetic laser-etched titanium promotes gene expression of early bone markers

Abstract

BACKGROUND CONTEXT Surface properties are a key factor in how bone interacts with an implant material. Accordingly, surface modification of materials can increase the prevalence of fast and stable fixation at the bone-implant interface. In particular, laser etching can be used to create surface pores designed to mimic osteoclast resorption pits. PURPOSE The aim of this study was to evaluate the osteogenic potential of smooth titanium (TS), polyether-ether-ketone (PEEK), and laser-etched titanium (TL) by comparing the capabilities of each substrate to promote bone-relevant gene expression. STUDY DESIGN/SETTING In vitro cell culture study. PATIENT SAMPLE Not applicable. OUTCOME MEASURES Cell viability was measured using a viability assay on day 1 and 7 for all materials. Gene expression was analyzed at day 1 and 7 using two-step RT-qPCR for the following markers of bone formation: alkaline phosphatase (ALP), vascular endothelial growth factor (VEGF), and RUNX2. METHODS Discs, 15 mm in diameter, of TS, PEEK, and TL were used to culture murine bone marrow mesenchymal stem cells (BM-MSCs). Cells were also cultured on tissue culture polystyrene (TCPS). Substrates were seeded with BM-MSCs at a density of ∼56×103 cells/cm2. Substrates were compared at each time point for gene expression and cell viability. RESULTS TL exhibited a higher cell count than TS and PEEK over 7 days, though significantly less than the TCPS at all time points. By D7, TCPS, TL, PEEK, and TS cultures resulted in the proliferation of (383±16, 162±7, 122±22, 47±45) x103 cells, respectively. The TL cell count was significantly (p CONCLUSIONS This study suggests that biomimetic patterning of titanium enhances the cellular response compared to titanium. Biomimetic, laser-etched titanium exhibited significantly higher cell counts and early bone markers than both smooth titanium and PEEK over 7 days. Further research using an animal model is required to assess the osseointegration potential of laser-etched titanium in vivo. FDA DEVICE/DRUG STATUS SINTROS (Globus Medical) (Approved for this indication)