Figure 4From: Contamination of nanoparticles by endotoxin: evaluation of different test methods Dose–response curve of TLR4 reporter cells without and with endotoxin inhibitor. Black line shows response ratio of TLR4 reporter cells by increasing concentrations of endotoxin. Red line shows response ratio when applied with endotoxin inhibitor (polymyxin B sulfate, 100 μg/ml). EC50: Half maximum effective concentration.Back to article page