HAHAHA, HEHEHE, HIHIHI, or HKHKHK : influence of position and composition of histidine containing tags on biodistribution of [(99m)Tc(CO)3](+)-labeled affibody molecules
Engineered affibody molecules can be used for high contrast in vivo molecular imaging. Extending a recombinantly produced HER2 binding affibody molecule with a hexa-histidine tag allows for convenient purification by immobilized metal-ion affinity chromatography and labeling with [(99m)Tc(CO)3](+) but increases radioactivity uptake in the liver. To investigate the impact of charge, lipophilicity,