摘要：Introduction: Acid Nucleic aptamers are short single-stranded oligonucleotides that display high affinity and selectivity for a given target. Aptamers contain many features that are advantageous for radiopharmaceuticals development. Peptidoglycan is a cell wall polymer common to both Gram-positive and Gram-negative bacteria. In the present study, the potential of two peptidoglycan aptamers for bacterial infection foci identification was evaluated. Material and methods: The peptidoglycan aptamers were labeled with 99mTc by the direct method and the stability of each 99mTc-aptamer complex was evaluated in saline, plasma and in presence of cysteine. The aptamers degradation by plasma nucleases was also assessed. Bacterial‑infected (Staphylococcus aureus) mice and fungal-infected mice (Candida albicans) were used for the ex vivo biodistribution studies with the 99mTc-aptamers. Results and discussion: The aptamers were not degraded by plasma nucleases. High radiolabel yields were obtained by the direct method and the complexes were stable in presence of saline and plasma. Some trans chelation was observed in the presence of cysteine. The 99mTc-pepdigoglycan aptamers uptake in the bacterial infection foci were significantly higher than the control (a radiolabeled oligonucleotide library) and their uptake in the fungal infection model. Conclusion: Both radiolabeled peptidoglycan aptamers present specific uptake in the bacterial infection foci highlighting the potential of these molecules as radiotracer for bacterial infection.
