Harnessing nanotechnology to combat antimicrobial resistance and accelerate wound healing
Imagine a wound that refuses to heal. It not only exhausts the body but also puts a person's life at risk daily due to infection risk. Today, chronic and purulent wounds have become a true "silent epidemic" for the global healthcare system, affecting millions of people worldwide 1 .
The problem of infectious complications is exacerbated by the growth of antimicrobial resistance. Studies show that 90% of Staphylococcus aureus strains isolated from wounds in hospital settings are already resistant to penicillin 1 . Under these conditions, medical science is turning to innovative solutions, among which zinc oxide nanoparticles occupy a special place - a semiconductor material capable of not only effectively fighting infections but also actively stimulating the tissue regeneration process 2 1 .
Chronic wounds affect millions globally with mortality rates comparable to some cancers.
Zinc oxide nanoparticles offer a novel approach combining antimicrobial action with regeneration stimulation.
Zinc - the second most abundant trace element in the human body after iron, contained in every cell 3 4 . It is an important cofactor for over 200 enzymes, directly participates in DNA and protein synthesis, regulates cellular growth and division 3 .
Essential for T-lymphocyte function, interferon-γ synthesis, and interleukin-2 production 3 .
Component of superoxide dismutase enzyme, helps neutralize free radicals 3 .
The transition from conventional zinc to nanoform significantly expands the therapeutic potential of this trace element. Zinc oxide nanoparticles (ZnO NP), which have a size of less than 100 nanometers, possess unique physicochemical properties due to their large surface area to volume ratio 1 . This provides them with high reactivity and allows more effective interaction with bacterial cells and tissue structures.
The antibacterial activity of zinc oxide nanoparticles is realized through several interconnected mechanisms, making them particularly effective against bacteria that have developed resistance to traditional antibiotics 6 .
ZnO nanoparticles can generate reactive oxygen species, such as hydrogen peroxide (H₂O₂) and hydroxyl radicals (•OH), which damage bacterial cellular structures - lipid membranes, proteins, and DNA, leading to microorganism death 7 .
Due to their small size and positive charge, nanoparticles can directly interact with the negatively charged surface of bacterial cells, destroying its integrity and leading to leakage of cellular content 8 .
Gradual release of Zn²⁺ ions inside the bacterial cell leads to inhibition of enzymatic activity and disruption of metabolic processes 1 .
Experimental studies confirm the effectiveness of zinc oxide nanoparticles against a wide range of pathogens that most commonly cause wound infections, including Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae 6 . Importantly, antibacterial activity increases with increasing nanoparticle concentration 6 .
| Bacterial Strain | Sensitivity to Zinc Oxide Nanoparticles | Notes |
|---|---|---|
| Staphylococcus aureus | High | Including methicillin-resistant strains (MRSA) |
| Escherichia coli | High | Gram-negative bacteria |
| Pseudomonas aeruginosa | Moderate to High | Ability to form biofilms |
| Klebsiella pneumoniae | High | Gram-negative bacteria |
| Proteus mirabilis | High | Causative agent of purulent wounds |
One of the most illustrative is a study published in 2022, in which scientists studied the effectiveness of silver-zinc oxide nanocomposites (Ag-ZnO/AgO NPs) in treating wounds in mice 9 .
The study was conducted on BALB/c mice, in which wounds were artificially created on the dorsal area. The mice were divided into two groups: control (untreated wounds) and experimental (wound treated with 1% Ag-ZnO/AgO nanocomposite). Treatment was carried out for 3, 7, 14 and 21 days, after which the following parameters were evaluated:
The results of the study were impressive. In mice that received nanocomposite treatment, acceleration of wound closure was observed compared to the control group. Histological analysis showed reduction of inflammatory infiltration and increased collagen synthesis. Also, increased activity of metalloproteinases 2 and 9 was detected, indicating active remodeling of the extracellular matrix 9 .
Importantly, the effective antibacterial concentration of nanocomposites showed no toxicity to mouse fibroblasts, indicating their safety for soft tissue cells 9 .
| Observation Day | Control Group (% Wound Closure) | Experimental Group (% Wound Closure) |
|---|---|---|
| Day 3 | 15-20% | 25-30% |
| Day 7 | 35-40% | 60-65% |
| Day 14 | 70-75% | 90-95% |
| Day 21 | 85-90% | 98-100% |
Modern technologies allow integrating zinc oxide nanoparticles into various biocompatible materials to create functional wound dressings. The most promising are bionanocomposites - materials that combine the biocompatibility of natural polymers with the antimicrobial activity of nanoparticles 1 .
Provide flexibility, transparency and gas permeability, making them ideal for burns 1 .
Create a moist environment favorable for healing and can absorb excess exudate 2 .
Mimic extracellular matrix structure, supporting cell migration and proliferation 1 .
Effective for wounds with significant exudation 1 .
| Dressing Type | Advantages | Application Indications |
|---|---|---|
| Film | Flexibility, transparency, gas permeability | Burns, superficial wounds |
| Hydrogel | Creation of moist environment, exudate absorption | Dry wounds, wounds with moderate exudation |
| Fibrous | Imitation of natural extracellular matrix | Deep and infected wounds |
| Foam | High absorption capacity | Wounds with significant exudation |
Conducting research in the field of zinc oxide nanoparticles for wound treatment requires the use of specialized reagents and materials. Here are the main components used in experiments:
Synthesized by chemical (e.g., precipitation from zinc nitrate and NaOH) or biological methods; basis of antimicrobial activity 6 .
Natural polymers (chitosan, alginate, cellulose, gelatin) serving as the basis for dressings, providing biocompatibility and promoting regeneration 1 .
Compounds that facilitate the introduction and uniform distribution of nanoparticles in the polymer matrix (e.g., plasticizers).
Standard antibiotics (gentamicin, ceftriaxone) used for comparison of effectiveness in vitro 6 .
Fibroblasts (e.g., L929 line) and keratinocytes for evaluation of cytotoxicity and proliferative activity 9 5 .
Reference strains of pathogens (S. aureus, E. coli, P. aeruginosa) for determination of antimicrobial activity 6 .
Research in recent years clearly demonstrates that zinc oxide nanoparticles have significant potential to revolutionize the treatment of purulent and chronic wounds. Their unique ability to combine powerful antibacterial activity (including against antibiotic-resistant strains) with stimulation of regeneration processes makes them an ideal candidate for creating new generations of wound dressings 2 1 .
Despite the promise, research in this field continues, particularly regarding optimization of nanoparticle concentration, improvement of integration methods into biomaterials, and deeper study of interaction mechanisms with human body cells 1 . An important task is also the standardization of methods for testing antibacterial properties to compare results of different studies 2 .
The future of purulent wound treatment is associated with the development of personalized approaches, when for a specific type of wound and microbial spectrum, the optimal composition of nanocomposite dressing will be selected. And zinc oxide nanoparticles will undoubtedly play one of the key roles in this, combining millennia of experience in using zinc in medicine with advanced nanotechnologies of the 21st century.