ENG and neoplasm: Administration of a blocking dose (1 mg/mouse) of free TRC105 at 1 h before 64Cu-HMSN-ZW800-TRC105 injection could significantly reduce the tumor uptake to 4.1 ± 1.7 and 5.5 ± 2.2%ID/g at 0.5 and 4 h p.i., respectively (n = 3, Figure 5c, Table S4), clearly demonstrating CD105 specificity of 64Cu-HMSN-ZW800-TRC105 in vivo.