Potential Application of Nanoparticles as Antipathogens - Advanced Materials for Agriculture, Food and Environmental Safety - page 341

Previous studies have shown that antimicrobial formulations in the
form of nanoparticles could be used as ef ective bactericidal materials
[53-54]. Recently, Klabunde and coworkers demonstrated that highly
reactive metal oxide nanoparticles exhibit excellent biocidal action against
Gram-positive and Gram-negative bacteria. h us, the preparation, char-
acterization, surface modii cation, and functionalisation of nanosized
inorganic particles open the possibility of formulation of a new generation
of bactericidal materials.

12.5.1 Gold Nanoparticles

h e major clinical use of gold NPs are in the treatment of rheumatic dis-
eases including psorosis, juvenile arthritis, palindromic rheumatism and
discoid lupus erythematosus. h e ei cacy of antibacterial activity of gold
nanoparticles can be increased by adding antibiotics. h e antimicrobial
activity of vancomycin was enhanced on coating with gold nanoparticles
against vancomycin resistant enterococci.
Further, the gold nanoparticles generate holes in the cell wall, resulting
in the leakage of cell content and cell death. It is also possible that gold
nanoparticles bind to the DNA of bacteria and inhibit the uncoiling and
transpiration of DNA.

12.5.2 Magnesium Oxide Nanoparticles

h e magnesium oxide (AP-MgO) nanoparticles exhibited biocidal activity
against certain vegetative gram-positive bacteria, gram-negative bacteria
and the spores..h eir extremely small size allows many particles to cover
the bacteria cells to a high extent and bring halogen in an active form in
high concentrations in proximity to the cell. Standard bacteriological tests
have shown excellent activity against E.coli and Bacillus megaterium and a
good activity against spores of Bacillus subtilis .

12.5.3 Copper Oxide Nanoparticles

Copper oxide (CuO) nanoparticles were ef ective in killing a range of bac-
terial pathogens involved in hospital-acquired infections [55]. However, a
high concentration of copper nanoparticles is required to achieve a bac-
tericidal ef ect [56]. h ese are very active against B. subtilis . h is may be
attributed to the greater abundance of amines and carboxyl groups on the
cell surface of B.subtilis and greater ai nity of copper towards these groups.