Relation between shape-tailored CeO₂ nanoparticles morphology and hemocompatibility and antimicrobial effect

Cerium is one of the most studied rare elements whose oxidative state (Ce³⁺ and Ce⁴⁺) can be changed in different environments. Cerium oxide nanoparticles (CeO₂ NPs), which are nevertheless more complex chemical structures, are nowadays very exciting entities involved in the biomedical field, particularly in the four stages of wound healing. In the first stage, called hemostasis, several issues such as the required morphology to be biologically efficient, and the effect of Ce³⁺ and Ce⁴⁺ on the applicability potential of CeO₂ NPs remain unclear. Our interest is focused in this study on the detailed understanding of the cations' location, when differently shaped CeO₂ NPs (i.e., nanocube, nanosphere, nanorod, and polyhedral particles) were used. Additionally, the present research highlights the applicability of nanoparticles in direct contact with blood and the antibacterial and antifungal properties of the samples. A correlation between the fungicidal properties of the samples and the Ce³⁺ cations formed on the surface was performed. The nanosphere/nanorod particles show the highest interaction with the hemoglobin (Hb). In addition, it was concluded that negatively charged surfaces favor the antibacterial properties using gram-negative bacteria. The morphologies' applicability will depend on the following parameters: surface area/volume ratio, crystallinity, hydrophilicity, Ce³⁺/Ce⁴⁺ ion distribution, and surface charge. Considering all these parameters and the nanoparticle applications, the nanorod will be the most suitable for antimicrobiological applications (antibacterial and antifungal), and showing the highest hemocompatibility.