DOTA-NHS-ester is a linker of affibody molecules for small animal PET, SPECT and CT. DOTA-NHS-ester can be used to label radiotherapeutic agents or imaging probes for tumor detection.

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 microPET imaging of an SKOV3 tumor-bearing mouse, 64Cu-DOTA-HSA-ZHER2:342 was administered via tail vein injection. Subsequent microPET images captured at 1, 4, 24, and 48 hours post-injection revealed the tumor's visibility. Initially, at 1 hour post-injection (p.i.), the tumor-to-background contrast was low, significantly improving at 4 and 24 hours p.i. to a very good level. Quantitative analysis indicated a progressive increase in SKOV3 tumor uptake over time, recorded at 5.63%, 9.98%, 14.34%, and 14.12% ID/g at 1, 4, 24, and 48 hours, respectively[1].