Fig. 4From: Vascular biosafety of commercial hydroxyapatite particles: discrepancy between blood compatibility assays and endothelial cell behaviorMetabolic activity of human endothelial cells exposed to HA particles, 1–1000 μg/mL. HAp1 and HAp2 decreased cell viability at levels ≥ 250 μg/mL and ≥ 50 μg/mL, respectively. *Significantly different from control (absence of particles); p ≤ 0.05Back to article page