The development and use of antibacterial materials to inhibit and kill harmful bacteria is an important aspect of improving human health. Traditional antimicrobial materials, such as antibiotics and quaternary ammonium salts, not only lead to microbial resistance but also cause serious environmental pollution. Nanomaterials are expected to be a new antibiotic substitute due to their strong transmembrane capacity, the ability to inhibit the efflux pump and the difficulty in inducing bacterial resistance.
Now let’s Immediate stocktaking of antibacterial nanomaterials!
Among the many metals and their oxide nanoparticles, silver nanoparticles have the best antimicrobial effect and the most extensive research. Many researchers have confirmed that silver nanoparticles have an effective inhibitory effect on bacteria, viruses, and fungi, especially on antibiotic-resistant strains.
The antibacterial effect of silver nanoparticles of different sizes is different. In addition to silver nanoparticles, other shapes of silver nanomaterials, such as silver nanowires, silver nanowires, and silver nanowires, also have antibacterial effects but have different antibacterial effects.
Due to its unique physical and chemical properties, gold nanoparticles have shown good antibacterial effects in vivo and in vitro, either as a carrier of antibacterial drugs or as a therapeutic agent after modification. Gold nanoparticles have a wide antibacterial spectrum, diverse antibacterial mechanisms, and good biocompatibility. However, the cognition of its structural stability, antibacterial mechanism, long-term safety and cytotoxicity of surface decoration in vivo still needs to be further studied and improved.
Using cysteine modified molybdenum disulfide loaded with silver ion, a new antimicrobial agent was constructed. This antimicrobial agent has a broad spectrum of bactericidal behavior and has obvious bactericidal behavior against gram-negative Escherichia coli and gram-positive Staphylococcus aureus. While this material has a strong killing ability against harmful bacteria, it has little effect on human cells.
Lyon et al. found that no reactive oxygen species were detected in the escherichia coli treated with C60, indicating that the antibacterial mechanism of C60 may not be dependent on the reactive oxygen pathway (Lyonetal2008). It has also been suggested that the antibacterial effect of fullerenes on prokaryotic cells is mediated by lipid peroxidation of cell membranes (Sayesetal2005). On the other hand, fullerenes have antiviral effects.
Friedman et al. found that C60 has an inhibitory effect on human immunodeficiency virus protease (HIV), and HIVP is the main target of antiviral therapy. Inhibition of HIVP can terminate the life cycle of HIV.
Antonio et al. combined fullerenes with many monosaccharides to synthesize a large spherical structure, which had an effective inhibitory effect on the ebola virus. However, the antibacterial mechanism of fullerenes is still controversial, and some scholars believe that fullerenes can cause photocatalysis to produce reactive oxygen species in eukaryotic cells.
At present, there are many reports on the antibacterial properties of carbon nanotubes, which have a good inhibitory effect on bacteria and fungi, and the antibacterial effect of single-walled carbon nanotubes is better than that of multi-walled carbon nanotubes.
Upadhyayula et al. demonstrated that single-walled carbon nanotubes have extremely high adsorption capacity, and their adsorption capacity to Bacillus subtilis spores is 27-37 times higher than that of activated carbon and nano-ceramics. The high adsorption capacity of single-walled carbon nanotubes mainly depends on their fibrous shape, extremely large aspect ratio and large specific surface area. In the same inch, CNTs had an extremely fast adsorption effect on bacteria. The results of the kinetic rate of adsorption of single-walled carbon nanotubes on Bacillus subtilis, staphylococcus aureus, and escherichia coli showed that 95% of the bacteria could adsorb to the surface of single-walled carbon nanotubes within 5-30 minutes.
The antibacterial properties of carbon nanotubes are affected by many factors. The single-walled carbon nanotubes with a small diameter are favorable for segmentation and easier to penetrate into the cell wall. Meanwhile, their large surface area is more favorable for contact and reaction with the cell surface.
Researchers explored the antibacterial properties of graphene oxide and found that the inhibition rate of graphene oxide nanosuspension after incubation with E. coli for 2 hours exceeded 90%. Further experimental results indicate that the antibacterial properties of graphene oxide stem from its damage to the cell membrane of E. coli. More importantly, graphene oxide is not only a new type of excellent antibacterial material but also has little cytotoxicity in mammalian cells. In addition, the graphene oxide can be prepared into a paper sheet-like macrographene film by suction filtration method, which can also effectively inhibit the growth of E. coli.
Hydroxyapatite (HA) has good biocompatibility and bioactivity, and good thermal stability. By ion exchange, silver ions are loaded on HA to obtain silver-loaded hydroxyapatite antibacterial agent, which is used in the later stage of wet processing of leather and spraying process. Other inorganic silver-bearing
antibacterial agents are good, and they are a promising inorganic antibacterial agent.
Other metal nanomaterials:
Nanoparticles such as gold, copper, zinc oxide, and titanium dioxide have antibacterial and antiviral activities. The heavy metals silver, copper, lead, mercury and other salts can react with sulfhydryl groups in proteins or replace metal ions in enzymes, inactivating most enzymes. Therefore, heavy metal ions have a broad spectrum of antibacterial and antiviral activities.
In addition to the above materials, graphene quantum dots, nitrogen carbide, nano-diamonds, etc., all exhibit huge antibacterial potential!