Dental floss is an oral hygiene tool, a thin filament designed to clean in between tooth surfaces. But imagine it as a vaccine delivery system, which would make it far more interesting. Researchers led by Dr. Harvinder Singh Gill, a Professor in Nanomedicine at North Carolina State University have discovered a special type of dental floss that delivers vaccines directly to the mucosal surfaces in the gums of mice.
According to a press release from North Carolina State university, Harvinder Singh Gill, corresponding author of the paper on the work says that, "Mucosal surfaces are important, because they are a source of entry for pathogens, such as influenza and COVID. However, if a vaccine is given by injection, antibodies are primarily produced in the bloodstream throughout the body, and relatively few antibodies are produced on mucosal surfaces."
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“But we know that when a vaccine is given via the mucosal surface, antibodies are stimulated not only in the bloodstream, but also on mucosal surfaces. This improves the body's ability to prevent infection, because there is an additional line of antibody defense before a pathogen enters the body.”
Nasal Sprays
Microneedle patches
Sublingual /buccal films
Intramuscular, intradermal & subcutaneous Injection.
Researchers selected the gingival sulcus, a groove between teeth and gums to deliver the vaccine due to its junctional epithelium, a thin tissue present in the base of gingival sulcus which is more permeable compared to other tissue surfaces.
"Because the junctional epithelium is more permeable than other epithelial tissues, and as a mucosal layer, it presents a unique opportunity for introducing vaccines to the body in a way that will stimulate enhanced antibody production across the body's mucosal layers. "Dr. Harvinder Singh Gill, Professor in Nanomedicine at North Carolina State University, USA
Researchers used flat dental floss as a carrier for various vaccine molecules. By flossing it between the teeth of mice, they successfully delivered components like peptides, proteins, and inactivated influenza virus into the gum tissue.
The study also revealed strong immune responses in mice, as antibodies against the influenza virus were effectively produced.
This method not only produces mucosal immunity but at the same time delivers the vaccine to the bloodstream effectively.
The floss-based method produces superior results compared to the sublingual route and nearly the same results as those given through the nasal epithelium.
It is painless compared to needles and can be given to patients with needle phobia.
It can be self-administered.
It doesn't need to be refrigerated unlike other vaccines.
"We found that applying vaccine via the junctional epithelium produces far superior antibody response on mucosal surfaces than the current gold standard for vaccinating via the oral cavity, which involves placing vaccine under the tongue. The flossing technique also provides comparable protection against flu virus as compared to the vaccine being given via the nasal epithelium. "Rohan Ingrole, first author of the paper, Ph.D. student under Gill at Texas Tech University
Researchers tested this vaccine delivery method in humans using floss picks. Twenty-seven participants received floss picks coated with food dye, and about 60% of the dye reached the gingival sulcus, suggesting promising results.
The study is still in preclinical trial stages, as more research is needed to determine how well the immune response is produced, whether it could be used in people with gum disease, and whether it could work in children who don't have teeth.
References
Ingrole, Rohan S. J., Akhilesh Kumar Shakya, Gaurav Joshi, Chang Hyun Lee, Lazar D. Nesovic, Richard W. Compans, and Harvinder Singh Gill. “Floss-Based Vaccination Targets the Gingival Sulcus for Mucosal and Systemic Immunization.” Nature Biomedical Engineering, July 22, 2025. Accessed February 13, 2026. https://pubmed.ncbi.nlm.nih.gov/40696115/.
North Carolina State University. “Scientists Pursue Vaccines Delivered via Dental Floss.” NC State News, July 24, 2025. Accessed February 13, 2026. https://news.ncsu.edu/2025/07/vaccines-via-dental-floss/