Studies on the antibacterial activities of molecular and liposomal systems bearing Zn(II) bisdipicolylamine complexes

Date

2024-7-12

Author

Şahin, Fulya

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Various approaches are being developed to address the antibiotic resistance problem. When developing new strategies, there are a few factors that need to be considered. One factor is that the developed method should be one that bacteria cannot easily develop resistance against. Photodynamic inactivation is a good option to achieve this. In PDI, agents called photosensitizers are exposed to light, producing molecules known as reactive oxygen species, which non-selectively kill bacterial cells. This process can be used repeatedly without the bacteria developing resistance. Another factor is that the method should be effective at low doses while being non-toxic even at high doses. A broad therapeutic window is desirable, as it provides a wider range of effective treatment doses. To achieve a wide therapeutic window, selectively targeting bacteria and utilizing liposomal encapsulation could be viable approaches. In this study, as PDI agents, different porphyrin derivatives were synthesized and conjugated to Zn2BDPA complexes, known for their ability to selectively target bacteria. This research examined how the presence of metalated and non-metalated porphyrin cores in these conjugates affected their PDI activity. Secondly, using cholesterol derivatized with Zn2BDPA as lipid-anchored bacterial targeting groups, different liposomes were prepared in the presence and absence of a photosensitizer, and their PDI activities were examined. Thirdly, to enhance the efficacy of rifampicin, an antibiotic in clinical use, it was encapsulated in liposomal formulations containing various amounts of Zn2BDPA-cholesterol conjugates as bacterial targeting groups and the in vitro activities of these formulations were investigated using the broth microdilution method.

Subject Keywords

Photodynamic therapy, Porphyrin, Bisdipicolylamine ligand, Liposome, Rifampicin

URI

https://hdl.handle.net/11511/110399

Collections

Graduate School of Natural and Applied Sciences, Thesis