Optimal composition and position of histidine-containing tags improves biodistribution of 99mTc-labeled DARPin G3

Radionuclide molecular imaging of HER2 expression in disseminated cancer enables stratification of patients for HER2-targeted therapies. DARPin G3, a small (14 kDa) engineered scaffold protein, is a promising probe for imaging of HER2. We hypothesized that position (C- or N-terminus) and composition (hexahistidine or (HE) 3 ) of histidine-containing tags would influence the biodistribution of [ 99m Tc]Tc(CO) 3 -labeled DARPin G3. To test the...