By Danielle 
Engineers have developed a novel method to deliver vaccines without needles — using dental floss.
In a study published July 22 in Nature Biomedical Engineering, researchers showed that vaccine-laced floss can deliver therapeutics through the junctional epithelium, a thin, porous tissue where the gums attach to the teeth, also known as the base of the gum pocket.
The floss, coated with gold nanoparticles carrying various vaccine components, including proteins, inactivated virus, immunogenic peptides, and messenger RNA, was used to immunize mice by flossing along their gumlines.
“Floss-based immunization induced strong and sustained immune activation across multiple organs, robust systemic and mucosal antibody responses, and durable protection against lethal influenza infection, independent of age, food and liquid consumption,” the authors wrote.
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Engineer recalls inspiration
Harvinder Gill, senior author of the study and now a professor at North Carolina State University, conducted the research while at Texas Tech University. Gill told Science he got the idea while reading about gum disease years ago. He learned that the gum pockets are especially permeable.
In the experiment, 50 mice were flossed every two weeks for 28 days with floss coated in an inactivated influenza virus. After the final dose, they were exposed to a lethal flu strain. All the mice that received three doses of the floss-based vaccine survived, while all unvaccinated mice died.
“These findings establish floss-based vaccination as a simple, needle-free strategy that enhances vaccine delivery and immune activation compared with existing mucosal immunization methods,” the researchers concluded.