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New Microgel Lubricant Could Provide Relief From Dry Mouth

A close-up side-on photo of a woman's mouth, wearing red lipstick.
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A novel aqueous lubricant that can be used as a saliva substitute to combat the effects of xerostomia, also known as dry mouth, has been developed by scientists at the University of Leeds.

The lubricant makes use of the material properties of microgels, a lattice-like network of molecules that bind onto the inside of the mouth. Surrounding the microgel is a polysaccharide-based hydrogel that also helps to trap in water and keep the mouth hydrated.

This dual-action lubricant technology is up to five times more effective than current commercial products, the researchers say. The research is published in the journal Scientific Reports.

New benchmarks for dry mouth care

Xerostomia affects roughly 1 in 10 adults, with this rising to approximately 30% of elderly adults and 80% of institutionalized elders. But dry mouth is more than just an important health issue due to its prevalence. It also significantly increases the risk of developing periodontal diseases, oral ulcers, tooth decay and swallowing problems. If left untreated, this can lead to reduced food intake and malnutrition.

To combat the negative effects of xerostomia, a wide range of different saliva substitutes have been developed to help rehydrate the mouth and act as a lubricant when chewing and swallowing food. However, a recent scientific review of such “artificial saliva” products found that any relief brought by such products tends to be short-lived. 

“The problem with many of the existing commercial products is they are only effective for short periods because they do not bind to the surface of the mouth, with people having to frequently reapply the substance, sometimes while they are talking or as they eat,” said lead study author Anwesha Sarkar, a professor of colloids and surfaces in the University of Leeds School of Food and Nutrition. “That affects people’s quality of life.”

The new microgel developed by Sarkar and her team is different, she explains, as the microgel structure is able to physically bind to biological surfaces, such as the dry inside of a mouth, due to a process called adsorption.

New saliva substitute is five times more effective than alternatives

The research team’s novel lubricant comes in two types: one made using a dairy protein, and a “veganized” version, made with a protein found in potatoes.

The researchers used an artificial tongue-like surface to measure the lubrication and desorption – the opposite of adsorption – properties of the lubricant on the tongue after a short rinsing, which mimics the swallowing process.

Similar tests were also conducted for eight commercially available saliva substitutes, including a drug store own-brand product, Biotene, Oralieve, Saliveze and Glandosane.

For the commercial products, between 23% to 58% of the lubricant was lost upon rinsing, compared to just 7% of the new saliva substitute. The dairy version of the substitute was also found to have marginally outperformed the vegan version.

“The test results provide a robust proof of concept that our material is likely to be more effective under real-world conditions and could offer relief up to five times longer than the existing products that are available,” said Olivia Pabois, PhD, a research fellow at the University of Leeds and first author of the paper.

“The results of the benchmarking show favorable results in three key areas. Our microgel provides high moisturization, it binds strongly with the surfaces of the mouth and is an effective lubricant, making it more comfortable for people to eat and talk.”

So far, the University of Leeds team has only tested the new saliva alternative in laboratory studies, though the team is looking to translate this technology into commercially available products that can complete human trials.


Reference: Pabois O, Avila-Sierra A, Ramaioli M, et al. Benchmarking of a microgel-reinforced hydrogel-based aqueous lubricant against commercial saliva substitutes. Sci Rep. 2023;13(1):19833. doi: 10.1038/s41598-023-46108-w

This article is a rework of a press release issued by the University of Leeds. Material has been edited for length and content.