Synthesis and Characterization of New Porphyrazine-Gd(III) Conjugates as Multimodal MR Contrast Agents
详细信息 查看全文
- 作者：Ying Song ; Hong Zong ; Evan R. Trivedi ; Benjamin J. Vesper ; Emily A. Waters ; Anthony G. M. Barrett ; James A. Radosevich ; Brian M. Hoffman ; Thomas J. Meade
- 刊名：Bioconjugate Chemistry
- 出版年：2010
- 出版时间：December 15, 2010
- 年：2010
- 卷：21
- 期：12
- 页码：2267-2275
- 全文大小：331K
- 年卷期：v.21,no.12(December 15, 2010)
- ISSN：1520-4812
文摘
Magnetic resonance imaging (MRI) has long been used clinically and experimentally as a diagnostic tool to obtain three-dimensional, high-resolution images of deep tissues. These images are enhanced by the administration of contrast agents such as paramagnetic Gd(III) complexes. Herein, we describe the preparation of a series of multimodal imaging agents in which paramagnetic Gd(III) complexes are conjugated to a fluorescent tetrapyrrole, namely, a porphyrazine (pz). Zinc metalated pzs conjugated to one, four, or eight paramagnetic Gd(III) complexes are reported. Among these conjugates, Zn-Pz-8Gd(III) exhibits an ionic relaxivity four times that of the monomeric Gd(III) agent, presumably because of increased molecular weight and a molecular relaxivity that is approximately thirty times larger, while retaining the intense electronic absorption and emission of the unmodified pz. Unlike current clinical MR agents, Zn-Pz-1Gd(III) is taken up by cells. This probe demonstrates intracellular fluorescence by confocal microscopy and provides significant contrast enhancement in MR images, as well as marked phototoxicity in assays of cellular viability. These results suggest that pz agents possess a new potential for use in cancer imaging by both MRI and near-infrared (NIR) fluorescence, while acting as a platform for photodynamic therapy.