1. Optimization of Artificial Siderophores as 68 Ga-Complexed PET Tracers for In Vivo Imaging of Bacterial Infections.
- Author
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Peukert C, Langer LNB, Wegener SM, Tutov A, Bankstahl JP, Karge B, Bengel FM, Ross TL, and Brönstrup M
- Subjects
- Animals, Cell Line, Tumor, Cyclams chemical synthesis, Cyclams pharmacokinetics, Cyclams toxicity, Escherichia coli, Gallium Radioisotopes chemistry, Humans, Male, Mice, Inbred C57BL, Muscles microbiology, Positron-Emission Tomography, Radiopharmaceuticals chemical synthesis, Radiopharmaceuticals pharmacokinetics, Radiopharmaceuticals toxicity, Siderophores chemical synthesis, Siderophores pharmacokinetics, Siderophores toxicity, Mice, Cyclams chemistry, Escherichia coli Infections diagnostic imaging, Radiopharmaceuticals chemistry, Siderophores chemistry
- Abstract
The diagnosis of bacterial infections at deep body sites benefits from noninvasive imaging of molecular probes that can be traced by positron emission tomography (PET). We specifically labeled bacteria by targeting their iron transport system with artificial siderophores. The cyclen-based probes contain different binding sites for iron and the PET nuclide gallium-68. A panel of 11 siderophores with different iron coordination numbers and geometries was synthesized in up to 8 steps, and candidates with the best siderophore potential were selected by a growth recovery assay. The probes [
68 Ga] 7 and [68 Ga] 15 were found to be suitable for PET imaging based on their radiochemical yield, radiochemical purity, and complex stability in vitro and in vivo. Both showed significant uptake in mice infected with Escherichia coli and were able to discern infection from lipopolysaccharide-triggered, sterile inflammation. The study qualifies cyclen-based artificial siderophores as readily accessible scaffolds for the in vivo imaging of bacteria.- Published
- 2021
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