54. Titanium plasma spray enhances ability of PEEK to express genes related to bone formation

Abstract

BACKGROUND CONTEXT Polyether-ether-ketone (PEEK) is a commonly used material in orthopedic implant applications. PEEK is often preferred for its radiolucency and mechanical properties that more closely resemble bone than metallic materials. However, several studies have shown that bone does not directly bond to PEEK. Titanium coatings have been hypothesized to improve the ability of PEEK to bond to bone while maintaining radiolucency. PURPOSE In the present study, we sought to evaluate cell-substrate interactions of smooth titanium (TS), PEEK, and titanium plasma sprayed PEEK (PT) by measuring the capability of each substrate to encourage bone-relevant gene expression. STUDY DESIGN/SETTING In vitro cell culture study. PATIENT SAMPLE Not applicable. OUTCOME MEASURES Cell count was evaluated using a cell viability assay on day 1, 7, and 14 for all materials. Gene expression was analyzed at day 1,7, and 14 using two-step RT-qPCR for the following markers of bone formation: Alkaline Phosphatase (ALP), Vascular Endothelial Growth Factor (VEGF), Osteocalcin (OCN), and RUNX2. METHODS Discs, 15 mm in diameter, of TS, PEEK, and PT 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 ∼56x103 cells/cm2. Substrates were compared at each time point for gene expression and cell viability. RESULTS PT substrates exhibited higher cell count than TS and PEEK over 7 days, though all substrates had significantly lower cell counts than TCPS at all time points. The PT cell count was significantly (p CONCLUSIONS Titanium plasma sprayed PEEK exhibited higher osteogenic gene expression and cell viability than both smooth titanium and PEEK over 14 days. Future research in an animal model is required to assess the osseointegration potential of titanium plasma-sprayed PEEK in vivo. FDA DEVICE/DRUG STATUS SUSTAIN (Globus Medical) (Approved for this indication)