Tissue distribution of65Zn post-gavage of65ZnO and SiO
-coated65ZnO NPs. Data are % dose of administered 65Zn in different organs. (A) At 5 minutes post-gavage, the 65Zn levels in tissues other than the gastrointestinal tract were much lower (0.3% for uncoated, 0.05% for coated 65ZnO NPs). (B) At day 7, significantly more 65Zn was absorbed and retained in non-GIT tissues (6.9% for uncoated, 6.0% for coated 65ZnO NPs). Significantly more 65Zn was measured in skeletal muscle in rat gavaged with uncoated versus coated 65ZnO NPs. (Note: RBC: red blood cell; sk muscl: skeletal muscle; sm int: small intestine: large int: large intestine).