Table 5.
MNPs (other than AgNPs) with reported activity against mycobacteria.
| MNP Type | MNP Morphology | Synthesis Process | Highlights | Ref. |
|---|---|---|---|---|
| Gold (AuNPs) | 15–30 nm sized, spherical and monodispersed | Chemically synthesized, stabilized with citrate, and Poly-allylamine hydrochloride (PAH) | Both citrate-AuNPs and PAH-AuNPs have activity against M. bovis (strain BCG), lower than tested AgNPs | [66] |
| Copper (CuNPs) | NR | Biologically synthesized from leaves of Psidium guajava L. | Activity against MTb, M. smegmatis, and M. pheli, but lower than other MNPs | [57] |
| Gallium (GaNPs) | 305 nm sized and cylindrical | Chemically synthesized by double emulsification and sonication | Polydispersed, with prolonged activity against intracellular M. smegmatis | [113] |
| Copper oxide and zinc oxide (Cu(II)ONPs and ZnONPs) | Spherical | Chemically synthesized | Activity against M. avium subsp. paratuberculosis | [69] |
| Bimetallic Silver-Gold (Au-AgNPs) |
10–70 nm sized and polydispersed | Phyto-synthesized from Barleria prionitis |
In vitro activity against MTb (strain H37Ra, active–MIC = 0.06–0.12 μg/mL, and dormant–MIC = 1.05–2.53 μg/mL) and M. bovis (strain BCG, active–MIC = 0.32–0.42 μg/mL, and dormant–MIC = 0.32–0.64 μg/mL), as well as ex vivo in THP-1 cells infected with MTb (active–MIC = 0.63–1.46 μg/mL, and dormant–MIC = 0.56–2.16 μg/mL) Higher activity than AuNPs or AgNPs (MIC ≈ 2.5 μg/mL), and more specific for mycobacteria with a higher selectivity index In addition, the smaller MNPs (from S. cumini) are more effective |
[60] |
| 90 nm sized and hexagonal | Phyto-synthesized from Plumbago zeylanica | |||
| 10–20 nm sized and spherical | Phyto-synthesized from Syzygium cumini | |||
| Zinc oxide (ZnONPs) | 12–53 nm sized and spherical | Biologically synthesized from leaves of Limonia acidissima Linn. also known as Feronia elephantum Correa or wood apple | Activity against MTb (strain H37Rv) | [114] |
| GaNPs | ≈300 nm sized and cylindrical | Chemically synthesized by double emulsification and sonication | Activity against intracellular MTb (strain H37Ra) in monocyte-derived macrophage (MDMs) and THP-1 macrophages (up to 70% MTb growth inhibition) | [115] |
| Zinc (ZnNPs) | ≈60 nm sized and variable shapes, mostly spherical | Biologically synthesized from Pseudomonas hibiscicola | Activity against MTb (strain H37Rv) and a clinical MDR MTb strain, (MIC = 1.25 mg/mL for both strains) | [78] |
| Titanium dioxide (TiO2NPs) | 16 nm sized and spherical | Chemically synthesized | Inhibited the growth of a clinical isolate of MTb (61%), and a clinical isolate of M. bovis (74%), at a concentration of 100 μg/mL. Effective surface coaters on inhibiting mycobacterial biofilm formation | [116] |
| Zinc oxide (ZnONPs) | 5.4–13.2 nm sized and spherical | Chemically synthesized | Activity against MTb (strain H37Rv) and XDR MTb strains (MIC = 1 μg/mL for both), and MDR MTb (MIC = 4 μg/mL) | [19] |
| Selenium (SeNPs) | Spherical | Chemically synthesized | Activity against M. smegmatis (MIC = 0.4 μg/mL), and MTb (MIC = 0.195 μg/mL). Low toxicity (compared to other MNPs) and involvement in reduction of the integrity of the mycobacterial cell envelope. Colloidally stable |
[117] |
MDR, multidrug resistant; MIC, minimum inhibitory concentration; MNPs, metallic nanoparticles; MTb, Mycobacterium tuberculosis; NPs, nanoparticles; NR, not reported; Ref., reference; XDR, extensively drug resistant.