Fungi are quietly winning a war that most people never see. They destroy between 10 and 23 percent of crops before harvest and another 10 to 20 percent after it, and they kill more than 1.6 million people every year, a toll roughly three times that of malaria and comparable to tuberculosis. Worse still, many pathogenic fungi have evolved resistance to the limited arsenal of antifungal drugs and fungicides available today. Against this backdrop, a comprehensive review published in Discover Biotechnology by K. Vijayalakshmi, T. Swaramanjari, M. Shanmugavel and A. Gnanamani makes the case that metal and metal oxide nanoparticles, produced through environmentally friendly biological synthesis, could become the next generation of antifungal agents.
The review focuses on green synthesis, a method that uses plant extracts, bacteria, yeast and fungi to manufacture nanoparticles rather than relying on the toxic chemicals and energy-intensive processes of conventional production. Materials with diameters between 1 and 100 nanometres behave fundamentally differently from their bulk counterparts because of their enormous surface-to-volume ratio, and the researchers argue that plants are the most practical biological factories for making them. Plant-derived synthesis is more economical than chemical routes, reduces pollution, and enhances environmental and human health safety. Crucially, the surface chemistry of each nanoparticle depends on the plant extract used, meaning that the choice of leaf, rhizome or peel extract can tune the final material’s properties. The bottom-up approach, in which nanoparticles are assembled atom by atom from precursor solutions, is generally preferred because it produces more uniform products with fewer defects and easier control over fabrication parameters.
Copper nanoparticles receive extensive attention, partly because copper is far cheaper than silver or gold, which matters enormously for agricultural deployment. Copper has been used against fungal disease since 1761, when seed grains soaked in mild copper sulfate solution were found to resist seed-borne fungi. The review documents striking results: a colloidal suspension containing just 7 parts per million of copper nanoparticles showed strong activity against Corticium salmonicolor, the agent of pink disease in rubber trees, when sprayed on infected plantations. In tea plantations, copper nanoparticles biosynthesised by the bacterium Streptomyces griseus achieved a 52.7 percent disease reduction at a dose of 2.5 parts per million, outperforming bulk copper, which managed only 45.3 percent. Nanoparticles made from Celastrus paniculatus leaf extract inhibited the mycelial growth of the wilt pathogen Fusarium oxysporum by up to 76.29 percent, while copper nanoparticles tested at 450 parts per million suppressed fungal growth by 93.98 percent over nine days of incubation.
Zinc oxide nanoparticles emerge as another standout, particularly attractive because zinc is generally safe for humans and causes little to no allergic response. The review reports that zinc oxide nanoparticles inhibited the growth of Aspergillus flavus by 37.81 percent at 500 parts per million and by 63.57 percent at 1000 parts per million, and that they strongly suppressed Rhizoctonia solani and Fusarium oxysporum, achieving 63.4 and 88.9 percent antifungal activity respectively at a concentration of 100 milligrams per millilitre. Against the post-harvest pathogens Botrytis cinerea and Penicillium expansum, doses above 3 millimoles per litre significantly inhibited growth. The proposed mechanisms are technically rich: zinc oxide nanoparticles generate reactive oxygen species on the fungal cell wall, potentially damaging DNA and denaturing proteins, while their ionic interaction with the wall leads to structural destruction. They may also disrupt membrane permeability, blocking the incorporation of lipids and proteins into the cell membrane, and possibly interfere with mitotic spindle division by targeting microtubules and inhibiting DNA transcription.
Silver nanoparticles, the most widely cited nanomaterial in the antimicrobial literature, occupy a special place in the review. Silver is toxic to fungi at very low concentrations, as little as 0.2 parts per million, while human health is largely unaffected at low doses, which explains its use in medical device coatings, orthopaedic and dental graft materials, wound dressings, water sanitisation and even textiles. The mechanistic detail is particularly compelling. Quantitative analysis of antifungal effects against Ustilaginoidea virens, the rice false smut fungus, showed that 2-nanometre silver particles were markedly more potent than 15-nanometre particles, with inhibition increasing dose-dependently between 0.5 and 10 micrograms per millilitre. Treated fungal cells showed altered ratios of phosphatidylcholine to phosphatidylethanolamine, a shift that destroys membrane integrity and function, along with a depletion of C18:2 phospholipids suggesting impaired desaturation. In Candida albicans, silver nanoparticles arrested the cell cycle at the G2/M phase, triggering reactive oxygen species production and depleting metal-based antioxidant enzymes.
The review also surveys less familiar candidates. Gold nanoparticles, valued for their chemical stability, oxidation resistance and biocompatibility, can be fabricated as nanorods, nanostars, nanobelts, nanospheres, nanocages and nanoprisms. Gold nanoparticles synthesised from Annona muricata showed zones of inhibition ranging from 30 to 66 percent against test fungi, with Penicillium camemberti most susceptible at 4 milligrams per litre, while gold particles made from Pongamia pinnata achieved 80 percent inhibition of a plant pathogenic fungus at just 0.8 milligrams per millilitre. Iron oxide nanoparticles, existing as magnetite, maghemite and hematite phases, showed activity against Candida albicans with a zone of inhibition of 53.67 millimetres when synthesised by the fungus Aspergillus terreus, and chitosan-coated iron oxide particles inhibited Fusarium solani, Candida albicans and Aspergillus niger. Magnesium oxide nanoparticles carry a Generally Recognised as Safe designation from the US Food and Drug Administration, making them especially promising, and particles derived from Citrus aurantium peel extract inhibited Candida albicans with a 26-millimetre zone of inhibition.
Selenium nanoparticles add a further dimension, since selenium is an essential trace element central to antioxidant defence in animal cells. Selenium nanoparticles fabricated with Bacillus subtilis showed stronger activity against Aspergillus species than against Candida, while particles synthesised by the fungus Trichoderma atroviride inhibited the mycelial growth of Colletotrichum capsici and Alternaria solani at 50 and 100 parts per million. Applied to tomato leaf blight caused by Alternaria alternata, selenium nanoparticles achieved an inhibition rate of 89.6 percent at 100 micrograms per millilitre, and at 80 parts per million they completely suppressed early blight disease in potatoes. Notably, the surface coating matters: selenium nanoparticles stabilised with poly-L-lysine showed the strongest antifungal action against the crop pathogen Sclerotinia sclerotiorum compared with polyacrylic acid or polyvinylpyrrolidone coatings. Copper oxide nanoparticles, meanwhile, achieved inhibition rates above 95 percent at low concentrations against Fusarium solani, Neofusicoccum species and Fusarium oxysporum.
Doping strategies push performance further. When zinc oxide is doped with metals such as iron, copper, cobalt or magnesium, or with non-metals and rare-earth elements, its electronic and optical properties change, often boosting reactive oxygen species generation. Iron-doped zinc oxide nanoparticles made with Hibiscus rosa-sinensis leaf extract inhibited Candida albicans with a 16.5-millimetre zone of inhibition, compared with 12.4 millimetres for undoped particles. In comparative studies, iron-doped zinc oxide at 40 microlitres matched the standard antifungal mycostatin against Aspergillus niger, magnesium-doped zinc oxide performed comparably to clotrimazole against Candida albicans, and biogenic silver-doped zinc oxide nanoparticles approached the activity of amphotericin B against Aspergillus flavus. Copper incorporation into zinc oxide structures was shown to enhance reactive oxygen species production and thereby increase antifungal efficacy against agricultural pathogens.
Underpinning all of these results is a coherent mechanistic framework. The review identifies three principal routes of fungal killing. The first is physical disruption: nanoparticles bind to the fungal cell wall and penetrate the membrane, causing structural damage and leakage of intracellular contents. Scanning electron microscopy comparisons against Candida glabrata revealed that silver nanoparticles created pores and distorted membranes, whereas gold nanoparticles induced no notable morphological changes, and gold particles have additionally been shown to cause nuclear condensation and DNA fragmentation in Candida albicans. The second route is oxidative stress: reactive oxygen species generated on particle surfaces, including hydroxyl radicals and hydrogen peroxide, damage DNA, proteins and lipids, with silver ions also complexing with thiols to prevent fungal detoxification. The third route is interference with cell signalling pathways, exemplified by chitosan nanoparticles, which interact with fungal cell walls and modulate pathways such as Toll-like receptor activation and the PI3K/AKT/mTOR cascade. In practice, these mechanisms often operate in combination, as with titanium dioxide nanoparticles, which both disrupt membranes and generate reactive oxygen species.
The authors are candid about the limitations. Almost all evidence to date comes from in vitro experiments, and in vivo studies are urgently needed to understand how these materials behave against fungal pathogens in living organisms. Safety evaluation must take centre stage, since metal and metal oxide nanoparticles can be toxic at high concentrations, as silver’s effects on freshwater and marine organisms demonstrate. The review calls for the synthesis and assessment of bimetallic and trimetallic nanoparticles, which may possess properties distinct from monometallic ones, along with standardised testing protocols to allow meaningful comparison across studies. Still, the overall message is one of genuine promise: nanoparticles exploit multiple simultaneous mechanisms of action, which lowers the risk of resistance development, and their small size, high surface area and tunable surface chemistry allow them to overcome the twin limitations of conventional antifungals, namely drug resistance and toxicity. If the safety and in vivo questions can be answered, plant-powered nanomaterials may soon protect both the world’s crops and its patients.
Subject of Research: Green-synthesized metal and metal oxide nanoparticles as antifungal agents
Article Title: Green-synthesized metal and metal oxide nanoparticles as emerging antifungal agents: current advances, mechanisms, and future perspectives
Article References: Vijayalakshmi, K., Swaramanjari, T., Shanmugavel, M., & Gnanamani, A. (2025). Green-synthesized metal and metal oxide nanoparticles as emerging antifungal agents: current advances, mechanisms, and future perspectives. Discover Biotechnology, 2(1), Article 18. https://doi.org/10.1007/s44340-025-00024-z
Image Credits: AI Generated
DOI: 10.1007/s44340-025-00024-z
Keywords: nanoparticles, green synthesis, antifungal agents, metal oxides, silver nanoparticles, zinc oxide, copper nanoparticles, reactive oxygen species, fungal resistance, plant pathogens, Candida albicans, nanotechnology
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Alan Morgan. (October 1, 2026). Plant-Powered Nanoparticles Emerge as Next-Generation Antifungal Weapons. Scienmag. https://scienmag.com/plant-powered-nanoparticles-emerge-as-next-generation-antifungal-weapons/
Alan Morgan. “Plant-Powered Nanoparticles Emerge as Next-Generation Antifungal Weapons.” Scienmag, 1 October 2026, https://scienmag.com/plant-powered-nanoparticles-emerge-as-next-generation-antifungal-weapons/. Accessed 1 October 2026.
Alan Morgan. “Plant-Powered Nanoparticles Emerge as Next-Generation Antifungal Weapons.” Scienmag. October 1, 2026. https://scienmag.com/plant-powered-nanoparticles-emerge-as-next-generation-antifungal-weapons/
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Tags: antifungal agentsantifungal resistancebiological nanoparticle synthesisCandida albicanscopper nanoparticlescrop protection nanotechnologyeco-friendly antifungal agentsenvironmentally friendly nanomaterialsfungal pathogen controlfungal resistancegreen synthesisgreen synthesis of nanoparticlesmetal oxide nanoparticles for fungimetal oxidesnanoparticlesnanotechnologynanotechnology in agricultureplant extract-mediated nanoparticle productionplant pathogensplant-based nanoparticlesreactive oxygen speciessilver nanoparticlessustainable antifungal solutionszinc oxide
