In vivotargeting and PET imaging using64Cu-labeled nano-graphene. (a) Schematic representation of conjugated nano-graphene. (b) Serum stability test of 64Cu-labeled nano-graphene shows that the vast majority of 64Cu remains intact on the GO after incubation in complete mouse serum at 37°C for 48 hrs. (c)In vivo PET/CT imaging of 64Cu-labeled GO conjugates in 4 T1 murine breast tumor-bearing mice. Serial coronal PET images of 4 T1 tumor-bearing mice at different time points post injection (p.i.) of 64Cu-NOTA-GO-TRC105, 64Cu-NOTA-GO, or 64Cu-NOTA-GO-TRC105 after a preinjected blocking dose of TRC105. Tumors are indicated by arrowheads. (d) Biodistribution studies in 4 T1 tumor-bearing mice. Biodistribution of 64Cu-NOTA-GO-TRC105 and 64Cu-NOTA-GO in 4 T1 tumor-bearing mice at 3 hrs and 48 hrs postinjection; *p < 0.05. Biodistribution of 64Cu-NOTA-GO-TRC105 and 64Cu-NOTA-GO-TRC105 after a blocking dose of TRC105 (denoted as blocking) in 4 T1 tumor-bearing mice at 48 h p.i. (Adapted with permission from Ref. 21. Copyright (2012) American Chemical Society).