Skip to main content
. 2021 Jan 20;11(2):263. doi: 10.3390/nano11020263

Table 2.

Antimicrobial activity of zinc oxide (ZnO) materials against pathogenic microorganisms.

Materials Synthesis Techniques
(Precursor)		 Material Description (Morphology/Particle Size) Antimicrobial Activity Test Methods Antimicrobial Activity against Pathogenic Microorganisms Refs.
ZnO materials
0D structured ZnO NPs Hydrothermal method or room temperature synthesis
(zinc nitrate hexahydrate; zinc sulfate; zinc acetate dihydrate)		 Spheres/12 nm, 25 nm; 30 nm, 88 nm, 142 nm, 212 nm, 307 nm Turbidity 6 mM,
[Staphylococcus aureus] 30 nm: 10.11% growth; 88 nm: 54.34% growth; 142 nm: 78.12% growth; 212 nm: 79.79% growth; 307 nm: 96.67% growth, [Proteus vulgaris] 12 nm: 8.71% growth, [Salmonella typhimurium] 12 nm: 46.96% growth, [Shigella flexneri] 12 nm: 5.95% growth, [Bacillus cereus] 12 nm: 7.62% growth		 [16]
Green method using Aloe vera leaf extract (zinc acetate dihydrate)

  • ▪ ZnO-1 & ZnO-2: hexagons and spheres/~63 nm; ~65 nm, and 60–180 nm

  • ▪ ZnO-3: cubes or rods/40–45 nm

 Well diffusion, broth microdilution; MIC MIC,
[E. coli] ZnO-1, ZnO-2, and ZnO-3: 1562 μg/mL; [S. aureus] ZnO-1: 781 μg/mL, ZnO-2 and ZnO-3: 391 μg/mL; [B. subtilis] ZnO-1 and ZnO-2: 391 μg/mL; ZnO-3: 195 μg/mL		 [17]
Precipitation method (zinc acetate dihydrate) Nanopyramids/~15.4 nm in segments Colony counting, serial dilution; MIC [Methicillin-resistant S. aureus (MRSA)] MIC, 333 μg/mL (3 log (CFU/mL) inhibition at 800 μg/mL) [96]
Soft chemical synthesis (micrometric ZnO) Spherical NP cluster/cluster-590 nm; NPs-63 nm Colony counting Antimicrobial activity value of log (control/sample),
[E. coli] > 3.5; [S. aureus] > 3.5		 [19]
1D structured ZnO NPs Hydrothermal method (zinc
acetate dihydrate)		 Hollow nanotubes/particle size ~500 nm in length; surface area 17.8 m2/g; average pore size, 278.6 nm Disk diffusion; MIC As-synthesized ZnO nanopowders,
MIC,
[Escherichia coli] 0.0585 mg/mL, [S. aureus] 0.234 mg/mL, [Pseudomonas aeruginosa] 0.234 mg/mL, [Bacillus subtilis] 0.938 mg/mL		 [54]
Atomic layer deposition process over polymer template and template removal Hollow nanotubes/length, ~5 μm; thickness, 59.5 nm; internal diameter, 178.2 nm Colony counting ZnO nanotubes at 1 wt% with acrylic polymer/extruded
32 μm-polyethylene (PE) substrate film coating
[E. coli] 4.67 log reduction (cells/cm2), [S. aureus] 2.46 log reduction (cells/cm2)		 [55]
Precipitation method (zinc nitrate) Nanorods/88.7 nm using 2-mercaptoethanol as a capping agent Disk diffusion method, serial dilution; MIC [Klebsiella pneumoniae] MIC, 40 μg/mL [99]
Green method using Chlorella vulgaris culture supernatant (zinc acetate dihydrate) Nanorods/crystal size, 3.4 nm; length-150 nm; width-21 nm (aspect ratio of length to width 7.14) Microdilution; MIC [E. coli, P. aeruginosa, S. aureus]
MIC, 250 μg/mL (excluding Enterococcus faecalis: resistant to ZnO nanorods)		 [100]
Sol–gel method (zinc nitrate hexahydrate) Nanorods/500 nm–1 μm Disk diffusion [Capping agent: ethylenediamine] E. coli-inhibition, Micrococcus luteus-no inhibition, [Capping agent: citric acid
monohydrate] E. coli-no inhibition, B. subtilis-inhibition		 [101]
2D structured ZnO NPs Not available (conventional products)

  • ▪ ZnO-1: platelets/14.7 nm

  • ▪ ZnO-2: platelets/17.5 nm

  • ▪ ZnO-3: rods, 76.2 nm

 Disk diffusion, broth dilution; MIC ZnO-1, ZnO-2, ZnO -3, MIC (wt%),
[E. coli] 0.12, 0.18, 2.30; [S. aureus] 0.25, 0.30, 3.40; [P. aeruginosa] 1.28, 4.68, 5.70; [Candida albicans] >8; >8; >8; [Aspergillus brasiliensis] nil, nil, nil		 [58]
3D structured ZnO NP network Sol–gel method (zinc acetylacetonate hydrate) Spherical NP aggregate network/aggregates: ~3 μm; NPs: 48.3 nm Colony counting; photocatalytic incubation [E. coli] {Dual UV for 30 s} no particles-~approx. 2.8–3.0 log (CFU/mL), 0.05 mg/mL-no colonies detected [18]
ZnO NP mixtures Green method using Butea monsoperma seed extract (zinc nitrate hexahydrate) Mixtures/25 nm Broth dilution; MIC [P. aeruginosa (resistant to amikacin (30 μg), cefepime (30 μg),
sparfloxacin (5 μg), piperacillin (100 μg), levofloxacin (5 μg), piperacilin-tazobactum
(100/10 μg), imipenem (10 μg), tobramycin (10 μg), nitrofurantoin (300 μg), and
ceftazidime (30 μg))] MIC, 1600 μg/mL; 1600–3200 μg/mL for isolates from patients 		[102]
ZnO MPs Flame transport synthesis (zinc microparticles) Tetrapods/~30 μm Plaque assay [Herpes simplex virus type-2 (HSV-2)] ZnO tetrapod NP and HSV-2 cocktail for live virus vaccine [95,103]
Green method using starch (zinc acetate) Self-assembled hollow microdonuts/1–2 μm Disk diffusion [Enterobacter aerogenes and Staphylococcus epidermidis] 0.5–5 mM [104]
Combinations of ZnO materials with drugs
ZnO NPs with azithromycin, gentamicin, oxacillin, cefotaxime, cefuroxime, fosfomycin, chloramphenicol, and oxytetracycline Green method using Ulva fasciata alga extract
(zinc acetate dehydrate)		 Flakes/length, ~200 nm Disk diffusion; MIC
  • ▪

    ZnO NPs: MIC, [E. coli, S. aureus, and Salmonella enterica subsp. Bukuru] 1.25 mg

    [C. albicans] no inhibition

  • ▪

    ZnO NPs (10 mg) with antibiotics: [E. coli] azithromycin, oxacillin, cefotaxime, cefuroxime, fosfomycin, oxytetracycline—synergistic, [S. aureus] azithromycin, cefotaxime, cefuroxime, fosfomycin, chloramphenicol, oxytetracycline—synergistic, [Salmonella spp.] oxacillin, cefuroxime, fosfomycin—synergistic, azithromycin, gentamicin, cefotaxime, neomycin, ampicillin/sulbactam, chloramphenicol, oxytetracycline—antagonistic

 [20]
ZnO with cephalexin nanohybrids Ion exchange via sol–gel method (ZnO, and 2,4-chlorophenoxyacetic acid) Squeezed ZnO crystals/not available Disk diffusion; MIC ZnO with cephalexin nanohybrids: MIC, [Aeromonas spp.] 1 mg/mL [21]
ZnO NPs with β-lactam antibiotics (ciprofloxacin and imipenem) Not available (conventional product) Not available Disk diffusion; agar dilution; MIC MIC

  • ▪ ZnO NPs: [E. coli] 0.08 mg/mL, [K. pneumonia] 0.05 mg/mL

  • ▪ ZnO NPs with ciprofloxacin: 0.2–1 mg/mL

  • ▪ ZnO NPs with imipenem: decrease in antimicrobial effect (except for one K. pneumonia strain)

 [79]
ZnO NPs with ceftriaxone (CFX-ZnO NPs), ceftazidime (CFZ-ZnO NPs), and gentamicin (GTM-ZnO NPs) Green method using Enterococcus faecalis culture supernatant (zinc sulfate) Spheres/15.3–37 nm Broth dilution; MIC

  • ▪ ZnO NPs: [E. coli, K. pneumonia, S. aureus, E. faecalis, P. aeruginosa, and S. flexneri] MIC, 4–16 μg/mL (P. aeruginosa > 64)

  • ▪ Antibiotics: [E. coli, K. pneumonia, S. aureus, E. faecalis, P. aeruginosa, and S. flexneri] MIC, 9–13 μg/mL

  • ▪ 24 h incubation: [E. coli] CFX-ZnO NPs 89–90% inhibition, [K. pneumonia] CFZ-ZnO NPs 96–99% inhibition, [S. aureus] GTM-ZnO NPs 95~98% inhibition, [E. faecalis] GTM-ZnO NPs 95% inhibition, [P. aeruginosa] CFZ-ZnO NPs 3.8% inhibition, [S. flexneri] CFZ-ZnO NPs 96% inhibition

 [105]
ZnO NPs with ampicillin/sulbactam Milling method (zinc chloride) Not available/25 nm Disk diffusion; broth dilution; MIC MIC,

  • ▪ Ampicillin/sulbactam: [E. coli, S. typhi, and S. aureus] 50 μg/mL, [K. pneumoniae, and P. aeruginosa] 100 μg/mL

  • ▪ ZnO NPs: 25–200 μg

  • ▪ ZnO NPs with ampicillin/sulbactam: [K. pneumoniae] 25 μg + 100 μg/mL, respectively

  • ▪ ZnO NP-ampicillin/sulbactam (conjugated form): [K. pneumoniae] 6.25 μg/mL

 [106]
Combinations of ZnO materials with other metal oxide NPs / MPs, or metal doping
ZnO NPs with TiO2 NPs in 4A zeolite Ion exchange process
(zinc acetate dehydrate)		 Cubes/400–600 nm (NPs: spheres, ~50 nm) Disk diffusion; MIC MIC,
[E. coli O157:H7] 1 mg/mL, [S. aureus] 2 mg/mL, [Pseudomonas fluorescens] 1 mg/mL, [Listeria Monocytogenes] 2 mg/mL		 [80]
Ag-ZnO·mSiO2 composites Precipitation of sodium water glass in zinc acetate solution (zinc acetate dihydrate) Lamellar porous nanostructure with silver spots/not available (specific surface area, 250 m2/g) Microdilution; MIC MIC, [E. coli] 2.9 mg/cm3, [P. aeruginosa] 3.9 mg/cm3, [Streptococcus salivarius] 5.9 mg/cm3, [S. aureus] 5.9 mg/cm3, [C. albicans] 23.5 mg/cm3—synergistic [81]
ZnO-SiO2 composites Solid state mixing (zinc acetate dihydrate)

  • ▪ Nanostructures on the silica surface/not available

  • ▪ NPs: nanorods/30–50 nm (specific surface area, 20–70 m2/g)

 Broth microdilution; MIC MIC, [S. aureus] 2 mg/mL (except for ZnO/S-S-20, C-A-10, or C-A-20, >2) as 0.228–0.632 mg/mL of ZnO NPs, [C. albicans] 1 or 2 mg/mL (except for ZnO/S-A-10 or S-S-10 >2) as 0.187–0.632 mg/mL of ZnO NPs [115]
CuZnO NPs on mesoporous silica SBA-3 Co-condensation method
(zinc nitrate)

  • ▪ Highly ordered mesoporous structure with relatively rough surface/not available

  • ▪ NPs: near-spheres/~2 μm (pore size, 3.6274 nm; specific surface area, 829 m2/g)

 Colony counting; MIC MIC, [E. coli] 25 mg/mL (CuZnO, 0.558 mg/mL), [S. aureus] 6.25 mg/mL (CuZnO, 0.139 mg/mL) [117]
ZnO MPs with TiO2 MPs Sol–gel method
(zinc chloride)

  • ▪ ZnO MPs: near-spheres/3.17–10.3 μm

  • ▪ TiO2 MP: near-spheres/2.15–37.1 μm

 Broth dilution; MIC; photocatalytic incubation under visible light irradiation ZnO MPs (0.25%) with TiO2 MPs (1%): [E. coli] 76.8% growth inhibition, [Streptococcus pyogenes] 70.2% growth inhibition, [K. pneumoniae] 80.8% growth inhibition [118]
Combinations of ZnO materials with other biomaterials
Chitosan
Chitosan-ZnO NP-loaded gallic acid (C-ZnO@gal) films
 Hydrothermal method
(zinc sulfate)
  • ▪

    ZnO@gal NPs: near-rods/~19.2 nm

  • ▪

    C-ZnO@gal films: homogeneous distributed of ZnO@gal NPs on chitosan matrixes (2 g chitosan/70 mg ZnO@gal)/not available (thickness 0.10 mm)

 Agar well diffusion 0.5 mg/mL,
[E. coli] 28 mm zone of inhibition,
[B. subtilis] 25 mm zone of inhibition		 [28]
ZnO NP-containing chitosan coating Not available (conventional product: 2% w/v solution, 10–30 nm)

  • ▪ ZnO NPs: near-spheres/~65 nm

  • ▪ ZnO NPs (1%) in chitosan matrix (2.5%) for coating: polymeric matrixes including uniformly distributed ZnO NPs/not available

 Broth dilution; MIC [E. coli O157:H7]
▪ Chitosan (2.5%, w/v): 2.5 log (CFU/g) reduction at 4 °C
▪ ZnO NP (1%, w/v)-containing chitosan (2.5%, w/v): 2.8 log (CFU/g) reduction at 4 °C		 [82]
ZnO NP-containing chitosan/gelatin hybrid nanocomposite (nZnO-chitosan/gelatin) films Green method using Cassia fistula fruit extract (zinc nitrate hexahydrate)

  • ▪ ZnO NPs: polyhedrons, quasi-spheres (2% in films), rods (4% in films)/20–40 nm, 500–1000 nm, 200–400 nm

  • ▪ nZnO-chitosan/gelatin films: evenly distributed NPs on smooth, compact, and heterogeneous surface/not available (thickness 86–92 μm)

 Disk diffusion [E. coli] ZnO NPs in films: 1%-10.5 mm zone of inhibition, 2%—10.5 mm zone of inhibition, 4%—10.7 mm zone of inhibition
[S. aureus] not prominent compared to E. coli 		[91]
3D porous ZnO NP-chitosan/silk/sericin scaffolds for wound dressing Not available (conventional product: solution, ~35 nm) Porous microstructures/not available
(porosity ~86%; pore size 4–200 μm)		 Disk diffusion 1.5 × 1.5 cm2, 2% (w/v) chitosan, 100 μL and 250 μL of ZnO NPs (40 wt% dispersion),
[E. coli] 2–4.5 mm zone of growth inhibition, [S. aureus] 2.5–5.5 mm zone of growth inhibition		 [136]
Chitosan-based ZnO nanocomposites Co-precipitation
(zinc acetate dihydrate)
  • ▪

    ZnO NPs: spheres/25–30 nm

    ▪ Chitosan-based ZnO nanocomposites for biodental meterials: stars/20–25 nm

 Disc diffusion Zone of inhibition (mm),
[K. pneumoniae] 13 mm (the highest) > [E. coli] > [P. aeruginosa] > [B. subtillis], [S. aureus], and [MRSA] 6 mm (the lowest)		 [137]
Hydroxyapatite & alginate
Hydroxyapatite-biphasic ZnO NP/MP-embedded alginate beads Precipitation (zinc nitrate)
  • ▪

    ZnO particles: snowflakes/<1 μm

  • ▪

    Hydroxyapatite- ZnO-alginate beads: distributed ZnO particles in bead matrixes/not available

 Agar diffusion; colony counting; MIC 0.1 mg/mL,
[E. coli] 56% inhibition, [P. aeruginosa] 65% inhibition,
[S. aureus and S. epidermidis] 100% inhibition		 [83]
Polyethylene glycol
Tungsten-doped polyethylene glycol-capped ZnO (W-PEG-ZnO) NPs Electrochemical method
(Zn electrodes)		 Near-spheres/~40.46 nm Agar well diffusion ▪ Ampicillin: 100 μg/μL [E. coli] 35 mm zone of inhibition, [B. cereus] 20 mm zone of inhibition
▪ W-PEG-ZnO NPs: [E. coli] 400–600 μg/μL, 5–6 mm zone of inhibition, [B. cereus] 300–600 μg/μL, 6–8 mm zone of inhibition		 [120]
K-carrageenan, bacterial cellulose, propolis extract& curcumin
Biopolymer K-carrageenan wrapped ZnO (KC-ZnO) NPs Precipitation
(zinc acetate dehydrate)		 KC-ZnO NPs: ovals/97 nm Disk diffusion; MIC [MRSA] MIC, 7.50 μg/mL [27]
Bacterial cellulose-ZnO NP-propolis extract (BC-ZnO-propolis) films Ultrasound
(zinc acetate)
  • ▪

    ZnO NPs: quasi-spheres/70–90 nm

  • BC-ZnO- propolis films: homogeneously distributed ZnO NPs on BC substrate surface/not available

 Disk diffusion; MIC; photocatalytic incubation (254 nm, 30 min) MIC,
[E. coli] >1.89 mg/mL,
[B. subtilis] 0.44 or <0.44 mg/mL,
[C. albicans] >0.8, 1.3, 1.89, >1.89 mg/mL		 [121]
Curcumin-loaded ZnO (C-ZnO) NPs Sol–gel method (zinc nitrate hexahydrate)
  • ▪

    C-sZnO: spheres/40–100 nm

  • ▪

    C-rZnO: rods/length, 600–900 nm (width, <300 nm)

  • ▪

    C-jZnO: javelin/300–600 nm (width, <300 nm)

  • ▪

    C-spZnO: short petal nanoflower/2–4 μm

  • ▪

    C-lpZnO: long petal nanoflower/~500 nm

 Well diffusion; colony counting Zone of inhibition (mm),
[E. coli] C-sZnO, 8.4; C-rZnO, 10.1; C-jZnO, 11.1; C-spZnO, 8.1; C-lpZnO, 9.8; C, 7.4
[S. epidermis] C-sZnO, 19.1; C-rZnO, 17.2; C-jZnO, 19.4; C-spZnO, 16.4; C-lpZnO, 20.1; C, 8.2
[S. aureus] C-sZnO, 15.4; C-rZnO, 16.6; C-jZnO, 13.4; C-spZnO, 15.2; C-lpZnO, 17.0; C, 8.1
[B. cereus] C-sZnO, 17.4; C-rZnO, 18.7; C-jZnO, 18.7; C-spZnO, 14.2; C-lpZnO, 14.2; C, 8.4		 [124]
Graphene, graphene oxide, & reduced graphene oxide
Graphene/ZnO nanocomposite films Ion exchange process
(zinc acetate)
  • ▪

    ZnO NPs: near-spheres/20–40 nm

  • ▪

    Graphene/ZnO nanocomposite films: ZnO NP-distributed graphene sheet/not available

 Microdilution; MIC [Streptococcus mutans] MIC, 125 μg/mL [84]
Graphene/ZnO nanocomposite with curcumin (C-ZnO) Ion exchange process
(zinc acetate dihydrate)
  • ▪

    ZnO NPs: spheres/35 nm

  • ▪

    Graphene/ZnO: homogenous distribution of ZnO NPs on graphene sheet/not available

 Agar diffusion; colony counting; microdilution; MIC MIC,
  • ▪

    Curcumin: 125 μg/mL

  • ▪

    Graphene/ZnO: [MRSA ATCC 43300] 125 μg/mL, [MRSA ATCC BAA-1708] 250 μg/mL

  • ▪

    Graphene/C-ZnO: [MRSA ATCC 43300] 31.25, [MRSA ATCC BAA-1708] 62.5 μg/mL (~64% inhibition of in vivo MRSA topical dermatitis infection)

 [85]
Graphene oxide (GO)/ZnO nanocomposite for wound care Co-precipitation
(zinc nitrate)		 ▪ GO: smooth and wrinkled surface layers/not available▪ GO/ZnO nanocomposite: well incorporated and distributed ZnO NPs (0.1–0.4 M) on GO sheets forming agglomerates/not available Disk diffusion, colony counting; dark (D) and visible light-irradiated (L) conditions Zone of growth inhibition (mm),
▪ ZnO NPs (0.4 M) on GO sheets, 100 μg/mL
[E. coli] GO-D, 11 mm; L, 11.5 mm; GO/ZnO (0.4 M)-D, 11 mm; L, 13 mm
[P. aeruginosa] GO-D, 10 mm; L, 10.5 mm; GO/ZnO (0.4 M)-D, 10 mm; L, 13 mm
[S. typhi] GO-D, 10.5 mm; L, 9 mm; GO/ZnO (0.4 M)-D, 11 mm; L, 11.5 mm
[S. flexneri] GO-D, 8 mm; L, 10.6 mm; GO/ZnO (0.4 M)-D, 12 mm; L, 12.5 mm		 [86]
GO/ZnO composites Ion exchange process
(zinc acetate dihydrate)
  • ▪

    ZnO NPs: rods/4 nm

  • ▪

    GO/ZnO composites: homogeneously anchored ZnO NPs onto GO sheets/not available

 Agar disk diffusion; MIC [E. coli] MIC, 2 μg [87]
Reduced graphene oxide (rGO)/ZnO films Sol–gel synthesis (zinc acetate dihydrate)
  • ▪

    ZnO NPs: spheres/~100–300 nm

  • ▪

    rGO/ZnO films: homogenous distribution of ZnO NPs on rGO sheet/not available (roughness, 159 nm)

 Serial dilution; colony counting; MIC; photocatalytic incubation (UV at 365 nm) [S. aureus] 1 wt% rGO
>99% (>2-log) reduction		 [88]
Cotton fabric
ZnO MPs-loaded chitosan-coated cotton fabrics Precipitation
(zinc chloride)		 Uniformly distributed dense microstructure of rods/not available Disk diffusion [E. coli] 2.5 cm zone of growth inhibition (ZnCl2 4%, chitosan 1–2%/1 g cotton fabric) [126]
Cotton-ZnO NP composites (C-nZnO) Precipitation
(zinc chloride)
  • ▪

    ZnO NPs: quasi-spheres/27 nm

  • ▪

    C-nZnO composites (8 types): thick condense layers of ZnO NPs on cotton surfaces/not available

 Disk diffusion; colony counting nZnO amounts in C-nZnO: 2.2, 1.7, 4.9, 4.3, 11.1, 7.8, 22.2, and 16.7 wt%
9 mm in diameter, [E. coli] 97–100% growth reduction, [S. aureus] 96–98% growth reduction		 [127]
ZnO NP-coated fabric Green method using starch
(zinc nitrate)
  • ▪

    ZnO NPs: spheres/200 nm

  • ▪

    ZnO NP-coated fabric: evenly distributed ZnO NPs on fabric surface/not available

 Colony counting 4.8 cm in diameter of fabric,
[E. coli] 80% reduction
[S. aureus] 99.99% reduction		 [129]
ZnO quantum dots (QDs)
Different nanostructure-based ZnO QDs (ZnO QD-1–ZnO QD-14) Sol–gel method
(zinc acetate dihydrate)		 Nanorods, nanotubes, nanospheres, nanowhiskers, nanoflowers/not available Agar well diffusion; agar dilution; MIC MIC,
[E. coli] ZnO QD-1: 25 mg/mL,
[Enterobacter aerogenes] ZnO QD-4 and ZnO QD-6: 25 mg/mL,
[K. pneumonia] ZnO QD-3 and ZnO QD-5: 12.5 mg/mL,
[P. aeruginosa] ZnO QD-3 and ZnO QD-7: 12.5 mg/mL,
[Bacillus anthracis] ZnO QD-2, ZnO QD-3 and ZnO QD-8: 6.25 mg/mL,
[S. aureus] ZnO QD-8: 6.25 mg/mL,
[L. monocytogenes] ZnO QD-6 and ZnO QD-7: 50 mg/mL,
[E. faecalis] ZnO QD-2 and ZnO QD-7: 25 mg/mL,
[B. cereus] ZnO QD-3 and ZnO QD-5: 12.5 mg/mL,
[S. epidermidis] ZnO QD-8: 1.5 mg/mL		 [89]
ZnO QDs Green method using Eclipta alba leaf extract
(zinc acetate dihydrate)		 Spheres/~6 nm Agar diffusion [E. coli] 15.69 mm zone of inhibition (1.6-fold increase compared to bulk zinc acetate at 5 mM) [90]
Antimicrobial peptide-based ZnO QDs containing vancomycin and methicillin (Van@ZnO-BSA-PEP-MPA; Met@ZnO-BSA-PEP-MPA) Precipitation
(zinc acetate)		 ZnO@BSA-PEP-MPA: spheres/104 nm Broth dilution; MIC; in vivo diagnostics-4 × 108 CFU S. aureus for infection and Van@ZnO-BSA-PEP-MPA at 5.0 mg/kg for theranostics MIC,
  • ▪

    ZnO@BSA-PEP-MPA: no inhibition (nanoprobe)

  • ▪

    Van@ZnO-BSA-PEP- MPA: [S. aureus] 2.0 μg/mL, [B. subtilis] 1.0 μg/mL (in vivo diagnostics: no changes in activity and body weight, 6 × 104 log (CFU/g) growth inhibition)

  • ▪

    Met@ZnO-BSA-PEP- MPA: [MRSA] 64 μg/mL

 [141]
Polyvinylpyrrolidone-capped ZnO (PVP-ZnO) QDs Precipitation
(zinc acetate hydrate)
  • ▪

    ZnO QDs: spheres/~5 nm

  • ▪

    PVP-ZnO QDs: highly crystalline spheres/~4 nm (smaller than ZnO QDs)

 Agar diffusion; colony counting
  • ▪

    ZnO QDs (1.12 mg/mL): [S. Enteritidis] 63.9% growth inhibition,

    [L. monocytogenes] 80.6% growth inhibition

  • ▪

    PVP-ZnO QDs (40 mg/mL): [E. coli O157:H7] 66.7% growth inhibition, [L. monocytogenes] 58.9% growth inhibition

 [142]