Evaluation of a Bispidine‐Based Chelator for Gallium‐68 and of the Porphyrin Conjugate as PET/PDT Theranostic Agent
Thomas W. Price, Steven Y. Yap, Raphaël Gillet, Huguette Savoie, Loı̈c J. Charbonnière, Ross W. Boyle, Aline Nonat, Graeme J. Stasiuk
Abstract
In this study a bispidine ligand has been applied to the complexation of gallium(III) and radiolabelled with gallium-68 for the first time. Despite its 5-coordinate nature, the resulting complex is stable in serum for over two hours, demonstrating a ligand system well matched to the imaging window of gallium-68 positron emission tomography (PET). To show the versatility of the bispidine ligand and its potential use in PET, the bifunctional chelator was conjugated to a porphyrin, producing a PET/PDT-theranostic, which showed the same level of stability to serum as the non-conjugated gallium-68 complex. The PET/PDT complex killed >90 % of HT-29 cells upon light irradiation at 50 μm. This study shows bispidines have the versatility to be used as a ligand system for gallium-68 in PET.