A gadolinium-based magnetic resonance imaging contrast agent for nucleotides sensing

A new magnetic resonance imaging probe( Gd-NAPTA) with 2-amino-7-methyl-1, 8-naphthyridine as the nucleotide triggering site incorporating into gadolinium-based contrast agent through 2,6-dimethylpyridine linker, preferentially responding to guanosine 5'-triphosphate and adenine 5'-triphosphate has been developed. The formation of strong multi-hydrogen bonds between naphthyridine and nucleotide bases made the phosphate in guanosine 5'-triphosphate and adenine 5'-triphosphate positioned on a suitable site to coordinate to the lanthanide ion, such the substitute of the coordinated pyridine promotes the water molecule close to Gd center and the relaxivity increase of the contrast agent. The longitudinal relaxivity(r(1)) of Gd-NAPTA could linearly respond to the concentration of guanosine triphosphate and adenine 5'-triphosphate. The limit of detection (LOD) is about 0.03 mM. The negligible cytotoxicity and appropriate blood circulation time of Gd-NAPTA allow potential application of Magnetic Resonance Imaging in vivo. (C) 2017 Elsevier B.V. All rights reserved.