Biodistribution comparison of AuNPs and AuNP-T cells in mice. Mice were injected with PEG-AuNPs (60-65 nm hydrodynamic diameter), AuNP-T cells, or PBS and subsequently sacrificed at various time points to determine biodistribution. PBS gold levels were negligible in comparison to AuNP and AuNP-T cell groups for all organs. Values are percentage of the injected gold dose (%ID) were calculated from ICP-MS and are normalized for dry weight differences. The AuNP-T cell group exhibited significantly higher gold delivery to the lungs, liver, and bone, while the AuNP group demonstrated higher gold levels within the small intestine. No significant differences were seen in the spleen, kidney, muscle, or brain. An asterisk indicates statistically significant (P < 0.05) differences.