Chitosan-coated cerium oxide nanoparticles and sparfloxacin encapsulated polymersomes as a new drug system with antimicrobial properties

Bacterial infections are a common problem worldwide. In the 20 century, because of the discovery of penicillin, for the first time, people had an effective way to fight bacterial infections. However, with the abuse of antibiotics, many bacteria are developing a resistance to such drugs. Now, bacteria can survive an antibiotic attack, making them more dangerous and potentially fatal to the patient. Nanoparticles have aroused interest as a new antimicrobial treatment due to their excellent ability to kill bacteria. Moreover, bacteria are less likely to develop resistance against nanoparticles because nanoparticles use a variety of different mechanisms to kill bacteria such as increased reactive oxygen species generation, blocking of membrane pores, etc. Herein, we synthesized novel cerium oxide nanoparticles (CeNPs) and tested their antibacterial properties due to their ability to change oxidative state with pH changes. Results showed that they are effective against Gram-positive bacteria like Staphylococcus epidermidis at 250 μg/ml. In contrast, cytotoxicity tests indicated that CeNPs are not toxic to human dermal fibroblasts (HDF) when the concentration is below 500 μg/ml. However, the problem with CeNPs is their tendency to agglomerate because of their tiny size and high surface energy, which reduces their efficiency. Therefore, we added chitosan to the CeNP suspension to provide a coating that reduces agglomeration. The chitosan-coated CeNPs (C-CeNPs) were better dispersed in water, and they showed better antimicrobial properties than CeNPs alone. Furthermore, we also used polymersomes as a novel nanocarrier for C-CeNPs and drugs which can help control drug release in the human body. After encapsulating CCeNPs and sparfloxacin (an antibiotic) together into polymersomes, this new drug system showed better antibacterial properties than just the drug itself, which indicates such nanodevices should be studied for a wide range of antibacterial applications.