Table 1 Factors related to morphology and experimental/methodology setup that might influence antibacterial activities of nanostructures of diverse shapes
From: Morphologic design of nanostructures for enhanced antimicrobial activity
Type of nanoparticle | Shape | Size | Method of preparation | Bacteria | Antibacterial assessment method (concentration of nanoparticles) | Exposure time of bacteria to nanoparticles | References |
|---|---|---|---|---|---|---|---|
Silver | Spheres Disks, Triangular plates | 39 nm 51 nm 51 nm | Chemical reduction | E. coli, S. aureus, P. aeruginosa | Disk diffusion (0.01 mg/mL) and optical density growth curve (0.1–0.7 mg/mL) | 24 h | [40] |
Silver | Spheres Rods | 40–60 nm 20–90 nm length × 20 nm width | Chemical reduction | E. coli, S. aureus, B. subtilis, P. aeruginosa, K. pneumoniae | Disk diffusion and (255–364 µg) minimum inhibitory concentration (184–358 µg/mL) | 24 h | [68] |
Silver | Spheres Rectangular Penta/hexagons | 2–5 nm; 40–50 nm 40–65 nm 50–100 nm | Green synthesis (fungal) | S. sonnei, E. coli, S. marcescens, S. aureus, P. aeruginosa | Disk diffusion and colony count | 24 h | [57] |
Silver | Spheres Truncated octahedral | 195 nm 194 nm | Chemical reduction | E. coli, Enterococcus faecium | Disk diffusion (100 µg/mL), optical density growth curve (50–1000 µg) | 1–24 h | [70] |
Silver | Nanospheres Nanocubes Nanowires | 60 nm 55 nm (edge length) 60 nm diameter × 2–4 μm length | Chemical reduction (microwave-assisted) | E. coli | Optical density growth curve (12.5–50 µg/mL), minimum inhibitory concentration (3–100 µg/mL) | 2–24 h | [42] |
Silver | Plates Rods Hexagonal | N/A | Chemical reduction | E. coli, S. aureus | Disk diffusion (5.4 ppm), minimum inhibitory concentration (0–100 ppm), Colony count (10 ppm) | 24 h | [41] |
Silver-loaded polymer nanoparticles | Spheres Cylinders Platelets | 11 nm 220 nm length × 20 nm diameter 620 nm length × 160 nm width | Crystallization-driven Self-Assembly | E. coli (uropathogenic strain UTI89 and laboratory strain MG1655) | Minimum inhibitory concentration (0.125–4 µg/mL Ag+) | 24 h | [52] |
Zinc oxide | Spheres Flower-like Rods | N/A | Solvothermal | S. aureus, E. coli | Colony count (20 ppm) –UV illumination | 24 h | [44] |
Zinc oxide | Spheres Hexagonal Cuboids | 60–180 nm 65 nm 45 nm | Green synthesis (Aloe vera leaf extract) | E. coli, B. subtilis, S. aureus | Agar well diffusion, minimum inhibitory concentration, minimum bactericidal concentration | 24 h | [56] |
Tin oxide | Spheres Cauliflowers Flower petals | 60–80 nm 96 nm 56 nm | Solvothermal | E. coli | Colony count – dark vs. visible-light vs. UV conditions | 24 h | [43] |
Quaternized poly(dimethyl-aminoethyl methacrylate) | Spheres Diamond-shaped platelets: Small Large | 136 nm 600 nm 3700 nm | Crystallization-driven Self-Assembly | E. coli, S. aureus, M. luteus, N. gonorrhoeae, P. aeruginosa, L. monocytogenes, B. subtilis | Minimum inhibitory concentration (62.5–2500 µg/mL) | 24–48 h | [15] |