Dentists recommend the use of dental floss. This is effective in preventing cavities and gum disease by removing food debris and plaque from between teeth where toothbrushes cannot reach. The efficacy of dental floss is expected to increase. Research findings have indicated that dental floss could also be utilized as a vaccine.
Researchers at the University of Texas at Austin's engineering school noted on the 22nd (local time) in the international journal Nature Biomedical Engineering that they developed a dental floss vaccine that delivers medication through the gums and confirmed its efficacy through animal experiments. The team successfully induced an immune response by delivering the vaccine to the gums of mice using dental floss.
Vaccines work on the principle of injecting inactivated viruses, bacteria, or parts of proteins into the body to generate an immune response. It's like preparing in advance for an attack by having prior experience with a small number of enemies, so when the real enemy comes, one can respond immediately. Vaccines are usually administered by medical staff with a syringe. From the patient's perspective, it is inconvenient as one has to go to the hospital, and the needle can also be burdensome.
To address these issues, various types of vaccines have been researched. A typical approach is the spray vaccine administered through the nose and mouth. However, there was a limitation in that vaccines are not properly absorbed in oral areas like under the tongue or on the palate.
Professor Harvinder Singh Gill from the University of Texas focused on existing research findings that indicate the gap between teeth and gums (gingival sulcus) absorbs molecules very well. He thought that using dental floss could deliver the vaccine into the body through this area.
Professor Gill used dental floss coated with fluorescent protein on the teeth of mice. The experiment showed that 75% of the fluorescent protein was delivered to the gums. This demonstrated the potential of dental floss to deliver vaccines. In fact, two months after using dental floss, antibodies against the fluorescent protein increased in the mice's lungs, noses, credit entries, and spleens, indicating the dental floss vaccine provoked an immune response.
The researchers coated the dental floss with inactivated influenza virus and used it on mice three times over a period of 28 days, at two-week intervals. Four weeks after the last dental floss application, 50 infected mice were exposed to live influenza virus. All mice that received the dental floss survived, while all other mice died.
Antibodies against the influenza virus were confirmed in the feces and saliva of the mice that received the dental floss treatment. There were many T cells, which are immune cells that kill viruses, in their lungs and spleens, and the lymph nodes that produce immune cells had also grown larger.
Professor Gill explained, "Even antibodies against the influenza virus were found in the bone marrow of the mice," adding that "this indicates that the immune system was fully activated by the influenza virus delivered through dental floss."
To determine whether the dental floss vaccine is effective in humans, the researchers had 27 healthy individuals use dental floss coated with edible dye. About 60% of the dye was delivered to the gums. This confirmed the potential effectiveness of the vaccine dental floss in humans. The experiment participants remarked that "the dental floss vaccine is much more convenient than vaccination with a syringe" and expressed their willingness to use it if it becomes available.
References
Nature Biomedical Engineering (2025), DOI: https://doi.org/10.1038/s41551-025-01451-3