Synthesis and characterization of monophosphinic acid DOTA derivative: A smart tool with functionalities for multimodal imaging

A new facile synthetic strategy was developed to prepare bifunctional monophosphinic acid Ln-DOTA derivatives, Gd-DO2AGAPNBn and Gd- DO2AGAPABn. The relaxivities of the Gd-complexes are enhanced compared to Gd-DOTA. Monophosphinic acid arm of these Gd-complexes affords enhancement of inner sphere water exchange rate due to its steric bulkiness. The different functionalities of DO2AGAPNBn were appended in trans positions and are designed to conjugate identical or different vectors according to the potential applications. The conjugation of Gd-DO2AGAPABn with E3 peptide known to target apoptosis was successfully performed and in vivo MRI allowed cell death detection in a mouse model.