New technique to treat middle ear infections – sciencedaily

The device – an array of microplasma jets – generates plasma, made up of charged particles and reactive molecules that have already been shown to inactivate various pathogens. “This is the first time that someone has tried to treat middle ear infections using plasma technology,” said Jungeun Won, a graduate student of the Boppart lab. “Usually, treatment involves the use of antibiotics or surgery.”

The problem with the use of antibiotics is twofold. First, antibiotics are ineffective in more than 30% of patients with acute infections. Second, their use can lead to increased resistance to antibiotics, as bacteria form biofilms, aggregates that attach to the surface of the ear.

“Biofilms are very dense, which makes it difficult for antibiotics to penetrate,” said Helen Nguyen (IGOH), Ivan Racheff professor of civil and environmental engineering. “Our idea was that if we could disrupt the structure of the biofilm, we could increase the penetration of antibiotics.”

The researchers tested the array of microplasma jets by building a model of the middle ear. They used an excised rat eardrum and tested the microplasm’s antimicrobial effects on bacteria behind the eardrum.

“We used different durations for the treatment and found that 15 minutes and more was effective in inactivating bacteria,” Won said. “We also monitored the fabrics to see if we had created any holes or breaks, but found no obvious physical damage.”

“We believe that the microplasm disrupts the biofilm by disrupting the bacterial cell membrane,” Nguyen said. “So far we only have indirect measures supporting our idea, but we will think about it in the future.”

Although the thickness of the rat’s eardrum is 30% less than that of a human, or about the width of a hair, the results suggest that microplasma treatment could be used to treat middle ear infections in the man.

“Middle ear infections and the over-prescribing of antibiotics to treat them are major clinical challenges that require new technologies and treatment solutions,” said Stephen Boppart, Grainger Distinguished Chair in Engineering, who is also a doctor.

Researchers are now designing a smaller array of atrium-shaped jets for treatments that will allow longer exposure times. They will also test the devices in animal models using biofilms of other bacteria that cause middle ear infections, including, but not limited to, Haemophilus influenzae, Streptococcus pneumoniae and Moraxella catarrhalis, to test whether the treatment is also effective with these bacteria. In addition, the researchers will closely monitor the tissues of the middle ear to ensure that there is no structural and functional tissue damage caused by the plasma technology.