A step towards gadolinium-free bioresponsive MRI contrast agent

• DOI: 10.1016/j.ejmech.2020.113086
• Publication Date: 2020-12-08T08:08:25Z
• Authors: Marzena Wyskocka-...; Łukasz Przypis; Monika Olesiejuk; Tomasz Krawczyk; Anna Kuźnik; Krzysztof Nawara; Masafumi Minoshima; Fuminori Sugihara; Kazuya Kikuchi; Nikodem Kuźnik
• Keywords: Biocompatibility; MRI contrast agent

The last 30 years of gadolinium-based "static" MRI contrast agents motivated to investigate bioresponsive agents with endogenous paramagnets. Iron(III) chelated by N,O-aminophenol skeleton of high versatility, and tuning potential was studied. The two-step convenient route of the ligand is characterized by high selectivity and allows for building a tunable chelate system. Functionalization with galactose endows a bioresponsive character sensitive to the enzyme activity. Direct relaxometric measurements of the resulting complexes revealed extremely high relaxivity of 5.62 mmol/dm3·s-1 comparable to classic gadolinium complexes. Enzymatic hydrolysis leads to relaxivity change by over 80%. Phantom MRI studies prove the bioresponsive character by contras percentage change within the range 40-275%. Cytotoxicity studies showed 70-90% viability of HeLa cells of the iron complexes. Proposed iron-based chelates with galactosidase-sensitive fragment express unequivocal relaxivity and MRI contras change and good biocompatibility. Therefore, these complexes are a promising step towards modern, bioresponsive MRI contrast agents with a "human-friendly" metal.