Preclinical evaluation of [68Ga]Ga-DFO for molecular imaging of Vibrio cholerae infection

In this study, a novel diagnostic radiopharmaceutical, [ 68 Ga]Ga-DFO, was developed for positron emission tomography (PET) imaging of the pandemic infection of Vibrio cholerae . The radiotracer was prepared at optimized conditions with high radiochemical purity (RCP). The stability of the agent in human serum and PBS buffer was assessed at different intervals. The partition coefficient (log P) was checked for [ 68 Ga]Ga-DFO. Then, in vitro studies including bacterial assay, competition with DFO-labeled compound, etc., were performed. Finally, the biodistribution and imaging studies have been conducted in four groups of healthy, subcutaneous infected, sterile inflamed, and gavage-feeding infected mice in different intervals. The RCP of the radiotracer at a temperature of 95 °C, pH 3.5, and a reaction time of 10 min, and 20 µg was 99.10 ± 0.5. The stability of the radiolabeled compound showed great stability in PBS and human serum. The mean Partition coefficient was −3.16 ± 0.27 proving the excellent hydrophilicity of the complex. The uptake of the radiolabeled DFO on the clinical strains of Vibrio cholerae demonstrated an %AD/g of 8432 ± 673. Competition tests showed the %AD/g of 11461 ± 1059, and 296 ± 42 for unblocked and blocked conditions, respectively. The biodistribution and imaging studies were performed in different mice groups demonstrating specific in vivo uptake of the radiotracer to Vibrio cholerae . The results suggest [ 68 Ga]Ga-DFO as a promising agent for PET imaging of pandemic bacterial infection of Vibrio cholerae .