Fig. 11. The four common mechanisms of the antimicrobial activity of Bi₂O₃ NPs-Nystatin, where (I) Bi₂O₃ NPs adhere to the surface of the pathogenic Candida cell and affect the membrane structure and penetrate the cell membrane due to their small size, (II) Bi₂O₃ NPs diffuse inside the Candida cells and associate with Candida organelles and bio-molecules, thereby changing the cellular mechanism and producing genotoxicity, (III) Bi₂O₃ NPs create ROS inside the Candida cells, which lead to the cell destruction, and (IV) Bi₂O₃ NPs change the cellular sign order, eventually inducing cell necrosis. Additionally, the Bi₂O₃ NPs may assist as a carrier to release Bi³⁺ ions more efficiently to the Candida cytoplasm and layer, in which the proton motive force may reduce the pH (below pH 3.5), which improves Bi³⁺ ions release. Nystatin alters the action of beta-glycan synthase and ergosterol construction and subsequently alters the permeability of the cell membrane and the transportation of ions inside the Candida cells.