Abstract:
A fluorescent ligand with polydentate amino carboxylate moieties was synthesized from tris(2-aminoethyl)amine and benzyl 2-bromoacetate,followed by the introduction of fluorescent functionality through an amidation reaction between the primary amine group and 6-carboxy-fluorescein.After coordination with paramagnetic GdC1
3·6H
2O,a bimodal contrast agent combing the ability for magnetic resonance imaging (MRI) and optical imaging was formed.The structures of the ligands and the complexes were confirmed by both H- and C-NMR、high resolution mass spectrometry,and ICP-AES.This new MRI contrast agent showed a
r1 value (longitudinal relaxivity) of 3.46 mM
-1·s
-1,comparable to commercial small molecular contrast agent like Magevist
®(Gd-DTPA).This complex also showed bright green fluorescence when shined with UV light,showing a high quantum yield of 66%,which is essential for clinical bimodal imaging.