Silver Nanoparticles in Antimicrobial Applications

Silver nanoparticles have emerged as a versatile and potent class of antimicrobial agents, leveraging unique physicochemical properties to combat a broad spectrum of pathogens. Their mechanisms of action extend from direct interaction with microbial cell envelopes, leading to membrane destabilisation and increased permeability, to the intracellular generation of reactive oxygen species that disrupt essential metabolic pathways. Beyond bactericidal effects, silver nanoparticles demonstrate significant efficacy against fungal and viral targets and can inhibit biofilm formation—an attribute critical to preventing chronic and device-associated infections. Surface functionalisation and conjugation with antibiotics or bioactive ligands further enhance specificity, reducing required dosages and mitigating cytotoxicity to host tissues. Advances in green synthesis and stabilisation techniques have improved particle uniformity and biocompatibility, while emerging studies on antiviral applications underscore their global significance in addressing multidrug-resistant and emerging infectious threats. Integration of silver nanoparticle platforms into coatings, wound dressings and delivery vehicles highlights their translational potential across clinical and environmental contexts.

Research from Nature Portfolio

Recent studies have advanced understanding of how silver nanoparticles disrupt virulence and biofilm architecture in multidrug-resistant organisms. Investigations into Acinetobacter baumannii models reveal that nanoparticle exposure not only inhibits planktonic growth but also downregulates expression of key biofilm-related and adhesion genes, yielding pronounced antibiofilm and antivirulence effects at minimal inhibitory concentrations. Alternative approaches that conjugate β-lactam antibiotics with silver have produced dual-function nanoformulations exhibiting superior bactericidal potency and sustained efficacy over repeated exposures, thwarting the emergence of resistance. Mechanistic insights further show that silver ions target thiol-dependent redox systems in Gram-negative bacteria, impeding the thioredoxin pathway, accelerating reactive oxygen species generation and potentiating conventional antibiotics through synergistic oxidative stress.

Silver Nanoparticles in Antimicrobial Applications publication trend

The graph below shows the total number of articles in silver nanoparticles in antimicrobial applications across all publications each year (not limited to Nature Index journals).

Technical terms

Silver nanoparticles (AgNPs): Nanoscale particles of elemental silver, typically 1–100 nm in diameter, with pronounced antimicrobial properties.

Minimum inhibitory concentration (MIC): The lowest concentration of an antimicrobial agent required to prevent visible growth of a microorganism in vitro.

Biofilm: A structured microbial community encased within a self-produced polymer matrix, adherent to biotic or abiotic surfaces.

Reactive oxygen species (ROS): Highly reactive molecules containing oxygen that can damage proteins, lipids and nucleic acids within cells.

Fractional inhibitory concentration index (FICI): A quantitative measure of drug interaction, where values below 0.5 indicate synergy between antimicrobial agents.

References

1. Synergistic Antimicrobial Activity of Silver Nanoparticles with an Emergent Class of Azoimidazoles. Pharmaceutics (2023).
2. Enhancement of antibiotics antimicrobial activity due to the silver nanoparticles impact on the cell membrane. PLOS ONE (2019).
3. Synergistic antibacterial and antibiofilm activity of silver nanoparticles biosynthesized by lignin-degrading fungus. Bioresources and Bioprocessing (2016).
4. Strong and Nonspecific Synergistic Antibacterial Efficiency of Antibiotics Combined with Silver Nanoparticles at Very Low Concentrations Showing No Cytotoxic Effect. Molecules (2015).
5. Enhancement of Antibacterial Activity of Capped Silver Nanoparticles in Combination with Antibiotics, on Model Gram‐Negative and Gram‐Positive Bacteria. Bioinorganic Chemistry and Applications (2013).
6. Synergistic Effects Between Metal Nanoparticles and Commercial Antimicrobial Agents: A Review. ACS Applied Nano Materials (2022).
7. Antibiofilm and antivirulence potential of silver nanoparticles against multidrug-resistant Acinetobacter baumannii. Scientific Reports (2021).
8. Ampicillin Silver Nanoformulations against Multidrug resistant bacteria. Scientific Reports (2019).
9. Synergistic antibacterial activity of silver with antibiotics correlating with the upregulation of the ROS production. Scientific Reports (2018).