ORGN 203 |
| An activatable, T1-weighted magnetic resonance imaging (MRI) contrast agent which tethers a spirooxazine molecule to a Gd-DO3A moiety was synthesized and characterized. The compound undergoes an isomerization upon stimulation with light or redox. When irradiated with UV light or with positive potential, the contrast agent is in its open form and has higher r1 relaxivity (bright in MRI). After irradiation with visible light or with negative potential, the contrast agent experiences a color change due to the partial isomerization to closed form (verified by absorption spectroscopy) and has lower r1 relaxivity (dark in MRI). The “indoline cap” above bound Gd3+ ion in closed isomer may prevent the water molecules from accessing the metal cation, thus inhibit MRI contrast enhancement and exhibit lower r1 relaxivity value. The contrast agent may allow direct, non-invasive and multidimensional observation of redox activity in deep tissues in vivo. |
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Total Synthesis, Materials, Devices and Switches, Molecular Recognition and Self-Assembly, Biologically-Related Molecules and Processes
8:00 PM-10:00 PM, Sunday, August 19, 2007 BCEC -- Exhibit Hall - B2, Poster
Division of Organic Chemistry |