Tiny Warriors Against Drug-Resistant Oral Thrush: Nanoparticles Show Promise

Oral candidiasis, the fungal infection commonly known as oral thrush, has long been a stubborn adversary in clinical medicine. Caused primarily by the yeast Candida albicans and, increasingly, by non-albicans Candida species, the infection afflicts infants, denture wearers, immunocompromised patients, and people with diabetes. Conventional antifungal drugs such as fluconazole, miconazole, nystatin, and chlorhexidine-based rinses have served as the mainstay of treatment for decades, but the steady rise of drug-resistant Candida strains has eroded their reliability. Now, a comprehensive scoping review published in BMC Pharmacology and Toxicology by researchers at Qazvin University of Medical Sciences and Tehran University of Medical Sciences in Iran has mapped the rapidly expanding landscape of nano-enabled therapeutics designed to overcome these limitations, and the picture that emerges is one of remarkable promise tempered by significant methodological fragmentation.

The review, led by Faezeh Azmoudeh and Niloofar Nazeri, followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews, known as PRISMA-ScR, to ensure a transparent and reproducible search strategy. The team queried three databases, Lens.org, PubMed, and Semantic Scholar, using combinations of search terms including nanoparticles, nanocarriers, nano-formulations, and oral candidiasis. The searches retrieved 990 records from Lens.org, 55 records from PubMed, and 141 records from Semantic Scholar. After screening for relevance to oral Candida infections and nano-enabled therapeutic applications, the researchers synthesized findings from studies spanning a broad range of nanomaterial platforms, with no restrictions on publication year. Both Candida albicans and non-albicans species were represented across the included literature, although with variable frequency, reflecting the dominant clinical role of C. albicans in oral disease.

What makes nanoparticles so attractive in the fight against oral fungi comes down to scale and mechanism. At dimensions measured in billionths of a meter, nanoparticles interact with microbial cells in ways that bulk drugs cannot. Metallic nanoparticles, for instance, can disrupt fungal cell membranes through direct physical contact, generate reactive oxygen species that inflict oxidative damage on cellular components, and interfere with essential metabolic pathways such as adenosine triphosphate production. Because these mechanisms differ fundamentally from those of conventional azole and polyene antifungals, which target ergosterol synthesis or membrane integrity through specific molecular interactions, nanoparticles can retain activity against multidrug-resistant strains that have evolved to evade traditional pharmacological attack.

The review catalogued an impressive diversity of nanomaterial platforms. Silver nanoparticles emerged as one of the most extensively studied systems, with numerous reports documenting enhanced antifungal activity and reduced minimum inhibitory concentrations against oral Candida isolates. Among the more creative approaches was the use of Zingiber officinale, or ginger, as a capping agent for silver nanoparticles, combining the antimicrobial properties of the metal with plant-derived biomolecules. Gold nanoparticles, including biosynthetically produced variants, were also evaluated, alongside titanium dioxide, copper oxide, and zinc oxide systems, the latter encompassing nano-zinc oxide and even zinc oxide quantum dots. Bismuth-based nanoparticles, including PVP-coated bismuth particles and bismuth dimercaptopropanol formulations known as BisBAL, added a less conventional but intriguing dimension to the metallic arsenal.

Beyond bare metal particles, the review highlighted the growing sophistication of functionalized and hybrid systems. Magnetic nanoparticles coated with aminosilane and conjugated with chlorhexidine, designated MNP@CHX, demonstrated the potential for externally controlled drug delivery, where an external magnetic field could guide and concentrate the therapeutic payload at the site of infection. Glucose oxidase-modified magnetic nanoparticles represented another clever design, exploiting enzymatic generation of antimicrobial species at the target site. These magnetically responsive systems, based on iron oxide cores, illustrate how nanotechnology enables not just enhanced killing but spatially targeted therapy, a particularly valuable property in the oral cavity where maintaining therapeutic concentrations of topical agents is notoriously difficult due to saliva flow and swallowing.

Lipid-based nanocarriers formed another major category in the reviewed literature. Solid lipid nanoparticles and nanostructured lipid carriers offer biocompatible matrices for encapsulating hydrophobic antifungal drugs, improving their solubility, stability, and sustained release. Fluconazole-loaded solid lipid nanoparticles were among the systems examined, as were miconazole-loaded chitosan nanoparticles, which pair a natural polysaccharide with a widely used azole drug. Chitosan itself possesses inherent antifungal and mucoadhesive properties, making it an ideal carrier material for oral applications, since it can prolong residence time on mucosal surfaces while simultaneously destabilizing fungal cell walls. Polymeric nanocarriers, including systems relevant to denture materials such as polymethyl methacrylate, extended the therapeutic concept beyond rinses and gels toward biomaterials with built-in antifungal protection.

The evidence assembled in the review consistently indicated enhanced antifungal activity for several nanoparticle systems, with reported benefits spanning direct fungal killing, mitigation of drug resistance, and improved targeted delivery within the oral environment. Studies evaluated outcomes through standard microbiological measures, including minimum inhibitory concentrations, minimum fungicidal concentrations, colony-forming unit counts, and membrane permeability assays using propidium iodide, complemented by imaging techniques such as field emission scanning electron microscopy. Both planktonic cells and biofilm states of Candida were addressed, the latter being particularly clinically relevant because biofilms on oral tissues and dental prostheses are far more resistant to antifungal agents than free-floating yeast cells.

Yet the review’s authors are careful to temper enthusiasm with a sober assessment of the field’s limitations. Heterogeneity in formulations, nanoparticle synthesis methods, dosing schemes, and outcome measures made direct comparison across studies difficult. Different research groups employed different Candida strains, different assay conditions, and different endpoints, meaning that the apparent superiority of one nanoparticle system over another often cannot be established with confidence. The variable representation of non-albicans Candida species, such as Candida glabrata and Candida krusei, which are increasingly important in clinical settings precisely because of their intrinsic resistance to common antifungals, further limits the generalizability of the accumulated evidence.

This fragmentation matters because the path from laboratory bench to dental chair is long and demanding. Before nano-enabled therapeutics can enter routine clinical use for oral candidiasis, researchers must resolve questions of safety, biocompatibility, and nanotoxicology, particularly for metallic nanoparticles whose accumulation in tissues remains a concern. Standardized testing protocols, clinically relevant infection models, and comparative head-to-head studies across Candida species are essential next steps that the review explicitly calls for. The authors emphasize that more standardized investigations, especially comparative studies across Candida species and clinically relevant models, are needed to translate the encouraging laboratory signals into evidence-based treatments.

Nevertheless, the scoping review arrives at a moment of genuine urgency in antifungal therapy. As drug-resistant Candida strains continue to spread and the immunocompromised population grows, the therapeutic pipeline desperately needs new mechanisms of action and new delivery strategies. Nano-enabled therapeutics offer both: mechanisms that circumvent conventional resistance pathways and delivery platforms that can localize potent agents precisely where they are needed. The Iranian team’s systematic mapping of the field provides researchers and clinicians with a consolidated view of what has been achieved and, just as importantly, a clear roadmap of what remains to be done. If the field can consolidate its fragmented evidence base and advance toward rigorous clinical evaluation, the tiny particles now battling Candida in laboratory dishes may one day become standard weapons against one of medicine’s most persistent oral infections.

Subject of Research: Nano-enabled therapeutic strategies for treating drug-resistant oral candidiasis

Article Title: Nano-enabled therapeutics for oral candida infections: a scoping review

Article References: Azmoudeh, F., Zarabadipour, M., Farshad, F., & Nazeri, N. (2026). Nano-enabled therapeutics for oral candida infections: a scoping review. BMC Pharmacology and Toxicology. https://doi.org/10.1186/s40360-026-01243-8

Image Credits: AI Generated

DOI: 10.1186/s40360-026-01243-8

Keywords: oral candidiasis, Candida albicans, nanoparticles, nanocarriers, antifungal resistance, silver nanoparticles, solid lipid nanoparticles, chitosan, magnetic nanoparticles, drug delivery, nanomedicine, scoping review