Synthesis and characterization of a redox- and light-sensitive MRI contrast agent

A redox- and light-sensitive, T-1-weighted magnetic resonance imaging (MRI) contrast agent, which tethers a spiropyran (SP)/merocyanine (MC) motif to a Gd-DO3A moiety was synthesized and characterized. When in the dark, the probe is in its MC form, which has an r(1) relaxivity of 2.51 m M (1)s (1) (60 MHz, 37 C). After irradiation with visible light or mixing with NADH, the probe experiences an isomerization and the r(1) relaxivity decreased 18% and 26%, respectively. Additionally, the signal intensity in MRI showed an observable decrease after the compound was mixed with NADH. (C) 2008 Elsevier Ltd. All rights reserved.