Figure 1From: Bioavailability, distribution and clearance of tracheally-instilled and gavaged uncoated or silica-coated zinc oxide nanoparticlesPhysicochemical characterization of test materials. Transmission electron micrograph of uncoated ZnO (A) and SiO2-coated ZnO (B) NPs. The thin silica coating of approximately 5 nm is shown in B, inset.Back to article page