HfO2 Nanoparticles Identify and Eliminate S Mutans

Dentistry Today


Researchers at the University of Illinois have devised a practical nanotechnology-based method for detecting and treating the bacteria that cause plaque and lead to tooth decay and other detrimental conditions.

“Presently in the clinic, detection of dental plaque is highly subjective and only depends on the dentist’s visual evaluation,” said Dipanjan Pan, PhD, associate professor of bioengineering and head of the research team.

“We have demonstrated for the first time that early detection of dental plaque in the clinic is possible using the regular intraoral x-ray machine, which can seek out harmful bacteria populations,” Pan said. 

Bioengineering graduate student Fatemeh Ostadhossein developed a plaque detection probe that works in conjunction with common x-ray technology and can find Streptococcus mutans in a complex biofim network. By tweaking the probe’s chemical composition, it also can be used to target and destroy S mutans

The probe comprises nanoparticles made of hafnium oxide (HfO2), a nontoxic metal currently under clinical trial for internal use in humans. The researchers have demonstrated the probe’s efficacy in identifying biochemical markers present on the surface of the biofilm and simultaneously destroy S mutans in Sprague Dawley rats. 

In practice, Pan envisions a dentist applying the probe on the patient’s teeth and using the x-ray machine to accurately visualize the extent of the biofilm plaque. If the plaque is deemed severe, the dentist will follow up by administering HfO2 nanoparticles in a dental paste.

The researchers also compared their HfO2 nanoparticles against chlorhexidine and found that the HfO2 was far more efficient at killing the bacteria and reducing the biofilm burden both in cell cultures of bacteria and in the infected rats.

Additionally, the researchers said their new technology is much safer than conventional treatment. They noted that the nanoparticles’ therapeutic effect is due to their unique surface chemistry, which provides a latch and kill mechanism.

“This mechanism sets our work apart from previously pursued nanoparticle-based approaches where the medicinal effect comes from antibiotics encapsulated in the particles, said Pan. “This is good because our approach avoids antibiotic resistance issues and it’s safe and highly scalable, making it well suited for eventual clinical translation.”

The study, “Dual Purpose Hafnium Oxide Nanoparticles Offer Imaging Streptococcus Mutans Dental Biofilm and Fight It In Vivo Via a Drug Free Approach,” was published by Biomaterials.

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