DOTA-NHS-ester is a linker for affibody molecules and is applied in small animals PET, SPECT, and CT. DOTA-NHS-ester can be used to label radiotherapeutic agents or imaging probes for the detection of tumors[1].

DOTA-NHS-ester can be used to modify human serum albumin (HSA) to produce DOTA-HSA. And DOTA-HSA is furtherly modified by Sulfo-SMCC to obtain DOTA-HSA-SMCC. DOTA-HSA-SMCC is conjugated to ZHER2:342 and the final product is DOTA-HSA-ZHER2:342[1]. In a cell uptake assay, DOTA-HSA-ZHER2:342 is labeled by 64Cu, 64Cu-DOTA-HSA-ZHER2:342 (0.5-2 hours) slowly accumulates in the SKOV3 cells and reaches 0.71% of the applied activity at 0.5 h and the uptake increased to 1.58% at 2 h[1].

In a microPET images of a mouse bearing SKOV3 tumor, 64Cu-DOTA-HSA-ZHER2:342 is injected to the mouse tail. microPET images of a mouse bearing SKOV3 tumor at 1, 4, 24 and 48 h after tail vein injection.The SKOV3 tumor is visible with a low tumor-to-background contrast at 1 h post-injection (p.i.), but with a very good tumor-to-background contrast at 4 and 24 h p.i.Quantification analysis reveals that the SKOV3 tumor uptake values increases with time and are found to be 5.63%, 9.98%, 14.34% and 14.12% ID/g at 1, 4, 24, and 48 h, respectively[1].

[1]. Hoppmann S, et al. Radiolabeled affibody-albumin bioconjugates for HER2-positive cancer targeting.Bioconjug Chem. 2011 Mar 16;22(3):413-2