Table 2.
Summary of carbon quantum dots synthesized from different carbon sources, their antibacterial activity and efficacy (i.e., MIC values).
| Carbon Source | Synthetic Method | Antibacterial Activity | Bacterial Strains Used | MIC * (µg/mL) |
Ref. |
|---|---|---|---|---|---|
| From Organic Reagents | |||||
| Polyamine, polyamine combined with ammonium, dopamine | Pyrolysis, microwave-assisted synthesis | Bacterial killing through cell wall damage; ROS generation | Gram-positive Staphylococcus aureus, Bacillus subtilis, Salmonella enterica, methicillin-resistant S. aureus (MRSA) |
0.9–8 | [19,37,38] |
| Gram-negative Escherichia coli, Pseudomonas aeruginosa |
0.9–8 | ||||
| Bis-quaternary ammonium salt | Hydrothermal method | Bacterial killing through cell wall damage; ROS generation; biofilm growth inhibition; biofilm dispersal through electrostatic interactions | Gram-positive MRSA, S. aureus |
2–4 | [47] |
| Gram-negative E. coli, ampicillin-resistant E. coli (AREC) |
8 | ||||
| Dimethyloctadecyl- [3-(trimethoxysilyl)propyl]ammonium chloride | Hydrothermal method | Biofilm dispersal through electrostatic and hydrophobic interaction with Gram-positive bacteria | Gram-positive S. aureus |
No MIC reported | [74] |
| Gram-negative E. coli |
No activity | ||||
| 3-[2-(2- aminoethylamino)ethylamino]propyl-trimethoxysilane, glycerol, quaternary ammonium compound lauryl betaine | Pyrolysis | Bacterial killing through cell wall damage | Gram-positive S. aureus, Micrococcus luteus, B. subtilis |
8 – 12 | [89] |
| Gram-negative E. coli, P. aeruginosa, Proteusbacillus vulgaris |
>200 | ||||
| Dimethyldiallyl ammonium chloride, glucose | Pyrolysis | Acted on ribosomal proteins in Gram-positive bacteria and downregulated metabolization-related proteins of Gram-negative bacteria | Gram-positive S. aureus, MRSA, Staphylococcus epidermidis, Enterococcus faecalis |
12.5–25 | [90] |
| Gram-negative E. coli, P. aeruginosa |
25–50 | ||||
| Diallyldimethylammonium chloride, 2,3-epoxypropyltrimethylammonium chloride | Pyrolysis | Affected protein translation, posttranslational modification and protein turnover | Gram-positive S. aureus, MRSA, S. epidermidis, Listera monocytogenes, E. faecalis |
5 – 20 | [91] |
| Gram-negative E. coli, Serratia marcescens, Salmonella paratyphi-β |
No activity | ||||
| Citric acid, l-glutathion, polyethene polyamine | Pyrolysis | Bacterial killing through cell wall damage; ROS generation | Gram-positive S. aureus, MRSA, L. monocytogenes, E. faecalis |
15–60 | [92] |
| Gram-negative E. coli, P. aeruginosa, S. marcescens, Drug-resistant P. aeruginosa, Drug-resistant E. coli |
120–480 | ||||
| Citric acid combined with aminoguanidine | Hydrothermal method | Bacterial killing through cell wall damage; biofilm growth inhibition | Gram-positive S. aureus, B. cereus |
No activity | [84] |
| Gram-negative E. coli, Salmonella enteritidis, Salmonella typhimurium, P. aeruginosa |
0.5–1 (P. aeruginosa), >1000 (other strains) |
||||
| Citric acid combined with branched polyethyleneimine, 2,3-dimethylmaleic anhydride | Hydrothermal method | Biofilm dispersal through electrostatic and hydrophobic interaction with Gram-positive bacteria | Gram-positive S. epidermidis |
No MIC reported | [75] |
| Gentamicin sulfate | Pyrolysis | Biofilm dispersal; bacterial killing through cell wall damage; ROS generation and maintenance of antibiotic features | Gram-positive S. aureus |
0.002 (at pH 5.5) |
[39] |
| Gram-negative E. coli |
0.203 (at pH 5.5) |
||||
| Ciprofloxacin hydrochloride | Hydrothermal method | Bacterial killing through maintenance of antibiotic features | Gram-positive S. aureus |
1.0 | [48] |
| Gram-negative E. coli |
0.025 | ||||
| Metronidazole | Hydrothermal method | Bacterial killing through maintenance of antibiotic features | Gram-positive S. mutans |
No activity | [49] |
| Gram-negative E. coli, Porphyromonas gingivalis |
No MIC reported | ||||
| Vitamin C | Electrochemical method | Bacterial killing through cell wall damage | Gram-positive S. aureus, Bacillus sp. WL-6, B. Subtilis |
No MIC reported | [61] |
| Gram-negative E. coli, AREC |
No MIC reported | ||||
| Poly-oxyethylene, -oxypropylene, -oxyethylene Pluronic 68 | Pyrolysis | Bacteria killing through ROS production upon blue light irradiation | Gram-positive S. aureus, B. cereus |
No MIC reported | [76] |
| Gram-negative P. aeruginosa |
No MIC reported | ||||
| From Inorganic Carbon Sources | |||||
| Carbon nanopowder, 2,2′-(ethylenedioxy) bis(ethylamine) | Acidic oxidation | Bacterial killing through ROS production upon visible light irradiation | Gram-positive B. subtilis |
64 | [24,29,30,34,93] |
| Gram-negative E. coli |
64 | ||||
| Graphite | Acidic oxidation | Bacterial killing through ROS generation under laser irradiation | Gram-positive MRSA, S. aureus |
No MIC reported | [31,32,33] |
| Gram-negative E. coli |
No MIC reported | ||||
| Carbon fibers | Acidic oxidation | Biofilm dispersal through interference with the self-assembly of amyloid peptides | Gram-positive S. aureus |
No MIC reported | [94] |
| From Natural Carbon Sources | |||||
| Lactobacillus plantarum | Hydrothermal methods | Biofilm growth inhibition | Gram-negative E. coli |
No MIC reported | [23] |
| Artemisia argyi leaves | Smoking | Bacterial killing by cell wall damage through cell wall-related enzyme inhibition | Gram-positive S. aureus, B. Subtilis |
No activity | [78] |
| Gram-negative E. coli, P. aeruginosa, P. vulgaris |
No MIC reported | ||||
| Cigarettes | Smoking | Bacterial killing through destruction of DNA double helix structure | Gram-positive S. aureus, AREC, B. subtilis |
No MIC reported | [79] |
| Gram-negative E. coli, kanamycin-resistant E. coli, P. vulgaris, P. aeruginosa |
No MIC reported | ||||
* MIC values for quantum carbon dots are based on weight per unit volume, but values may not be directly comparable with the traditional MIC value of antibiotics. MIC values of antibiotics refer to the weight of dissolved molecules, while carbon quantum dots are nanoparticles with diameters that are larger than of molecules.