Intracellular Transport Studies of Picolinate Macrocyclic Copper and Lanthanide Complexes

Abstract

AbstractIn vivo molecular imaging involves different techniques to image cellular biochemical processes. Metal complexes can be used as cell‐permeable medical imaging agents. In this work we studied the cytotoxicity and the cellular incorporation kinetics of two recently synthesized picolinate macrocyclic complexes, [Eu(do2pa)]+ and [Cu(te1pa)]+. Both complexes are able to enter inside the cells. The intracellular concentration (Ci) of [Eu(do2pa)]+ is ∼5 times the extracellular concentration (Ce). In the case of [Cu(te1pa)]+, the ratio Ci/Ce is approximately 1.4. Furthermore, the results suggest that these complexes are not substrates of P‐gp, an efflux transport protein involved in the mechanisms of multidrug resistance in cancer cells and in the low permeability of blood‐brain barrier. The results obtained here, added to their physicochemical properties, let us propose that the complexes studied could be suitable platforms for the synthesis of cell‐permeable MRI contrast agents or PET tracers.