Antimicrobial Activity of Zinc Oxide Nano/Microparticles and Their Combinations against Pathogenic Microorganisms for Biomedical Applications: From Physicochemical Characteristics to Pharmacological Aspects

Abstract

Zinc oxide (ZnO) nano/microparticles (NPs/MPs) have been studied as antibiotics to enhance antimicrobial activity against pathogenic bacteria and viruses with or without antibiotic resistance. They have unique physicochemical characteristics that can affect biological and toxicological responses in microorganisms. Metal ion release, particle adsorption, and reactive oxygen species generation are the main mechanisms underlying their antimicrobial action. In this review, we describe the physicochemical characteristics of ZnO NPs/MPs related to biological and toxicological effects and discuss the recent findings of the antimicrobial activity of ZnO NPs/MPs and their combinations with other materials against pathogenic microorganisms. Current biomedical applications of ZnO NPs/MPs and combinations with other materials are also presented. This review will provide the better understanding of ZnO NPs/MPs as antibiotic alternatives and aid in further development of antibiotic agents for industrial and clinical applications.

Multiscale Metal Oxide Particles to Enhance Photocatalytic Antimicrobial Activity against Escherichia coli and M13 Bacteriophage under Dual Ultraviolet Irradiation

“…On the contrary, low antimicrobial activities were detected in MO microparticles (MPs, >100 nm) against Escherichia coli and Staphylococcus aureus, which ranged from 0.1 to 0.8 µm in diameter with specific surface area of 0.85-26.0 m 2 /g [9]. However, the photocatalytic disinfection potential of MO MPs can be improved in ROS generation under UV irradiation based on the porosity via multiple scattering phenomena for enhanced mass transfer and exchange rate [13,14]. In addition to MO NPs or MPs alone, photocatalytic antimicrobial activity of multiscale MO particles can be monitored as mixtures of MO NPs and MPs.…”

Inorganic Nanoparticles and Composite Films for Antimicrobial Therapies

“…Specifically, the positively charged ZnO NPs interact with the negatively charged microbial cell walls or membranes through electrostatic forces. Subsequently, ZnO NPs attach onto the surface and distort the membrane structure, further leading to the internalization of the NPs within the cell and the loss of cell integrity, leakage of the intracellular components, and cell death [ 102 , 105 , 106 , 107 , 108 , 109 ]. On one hand, once internalized, NPs will release Zn 2+ ions, which will interfere with metabolic and enzymatic processes and induce cell death [ 102 , 105 , 106 , 108 , 109 ].…”

“…Subsequently, ZnO NPs attach onto the surface and distort the membrane structure, further leading to the internalization of the NPs within the cell and the loss of cell integrity, leakage of the intracellular components, and cell death [ 102 , 105 , 106 , 107 , 108 , 109 ]. On one hand, once internalized, NPs will release Zn 2+ ions, which will interfere with metabolic and enzymatic processes and induce cell death [ 102 , 105 , 106 , 108 , 109 ]. On the other hand, NPs will generate ROS, such as superoxide anion, hydroxyl ion, and hydrogen peroxide, from their surface, causing oxidative stress by lipid peroxidation, DNA replication disruption and DNA damage, energy metabolism and cellular respiration inhibition, slow leakage of RNA, and rapid leakage of K + ions [ 102 , 105 , 106 , 107 , 108 , 109 ].…”

“…On one hand, once internalized, NPs will release Zn 2+ ions, which will interfere with metabolic and enzymatic processes and induce cell death [ 102 , 105 , 106 , 108 , 109 ]. On the other hand, NPs will generate ROS, such as superoxide anion, hydroxyl ion, and hydrogen peroxide, from their surface, causing oxidative stress by lipid peroxidation, DNA replication disruption and DNA damage, energy metabolism and cellular respiration inhibition, slow leakage of RNA, and rapid leakage of K + ions [ 102 , 105 , 106 , 107 , 108 , 109 ]. Similarly, ZnO NPs enter fungal cells through diffusion and endocytosis, where they hinder mitochondrial functioning and cause irreversible nucleic acid and chromosome damages through Zn 2+ release and ROS production [ 108 ].…”

“…The release of Zn 2+ ions depends on the physico-chemical and morphological properties of the NPs [ 105 , 106 , 109 ]. Specifically, a particle size decrease results in superior antimicrobial properties [ 106 ], while rod-like structures lead to reduced Zn 2+ ion release when compared to spherical NPs [ 102 ].…”