Bispidines for Dual Imaging |
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Authors: | Dr Holger Stephan Dr Martin Walther Dr Silke Fähnemann Prof Paola Ceroni Dr Jennifer K Molloy Dr Giacomo Bergamini Dr Fabian Heisig Prof Christa E Müller Werner Kraus Prof Peter Comba |
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Institution: | 1. Helmholtz‐Zentrum Dresden‐Rossendorf, Institute of Radiopharmaceutical Cancer Research, PF 510119, 01314 Dresden (Germany), Fax: (+49)?351‐2603232;2. Department of Chemistry “G. Ciamician”, University of Bologna, Via Selmi 2, 40126, Bologna (Italy), Fax: (+49)?6226‐546617, Fax: (+49)?0512099456;3. PharmaCenter Bonn, Pharmaceutical Institute, Chemistry I, University of Bonn, An der Immenburg 4, 53121 Bonn (Germany);4. BAM, Bundesanstalt für Materialforschung und ‐prüfung Richard‐Willst?tter‐Stra?e 11, 12489 Berlin (Germany);5. Universit?t Heidelberg, Anorganisch‐Chemisches Institut, INF 270, 69120 Heidelberg (Germany), Fax: (+49)?6221‐546617 |
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Abstract: | The efficient transformation of the hexadentate bispidinol 1 into carbamate derivatives yields functional bispidines enabling convenient functionalization for targeted imaging. The BODIPY‐substituted bispidine 3 combines a coordination site for metal ions, such as radioactive 64CuII, with a fluorescent unit. Product 3 was thoroughly characterized by standard analytical methods, single crystal X‐ray diffraction, radiolabeling, and photophysical analysis. The luminescence of ligand 3 was found to be strongly dependent on metal ion coordination: CuII quenches the BODIPY fluorescence, whereas NiII and ZnII ions do not affect it. It follows that, in imaging applications with the positron emitter 64CuII, residues of its origin from enriched 64Ni and the decay products 64NiII and 64ZnII, efficiently restore the fluorescence of the ligand. This allows for monitoring of the emitted radiation as well as the fluorescence signal. The stability of the 64CuII? 3 complex is investigated by transmetalation experiments with ZnII and NiII, using fluorescence and radioactivity detection, and the results confirm the high stability of 64CuII? 3 . In addition, metal complexes of ligand 3 with the lanthanide ions TbIII, EuIII, and NdIII are shown to exhibit emission of the BODIPY ligand and the lanthanide ion, thus enabling dual emission detection. |
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Keywords: | bispidines chelates imaging agents lanthanides radiolabeling |
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