According to the US National Institute of Biomedical Imaging and Bioengineering, sugar-coated gold nanoparticles can kill stubborn bacteria that grow on teeth and potentially eliminate biofilms faster than antibiotics.
The animal study highlights the diagnostic and therapeutic potential of these newly developed nanoparticles and their potential in reducing antibiotic resistance.
“This treatment method is especially rapid for oral infections,” Mariam Hajfatalian, Ph.D., professor of biomedical engineering at the New Jersey Institute of Technology, said in a press release. “We used the laser for one minute, although in fact in about 30 seconds we kill almost all the bacteria.”
Bacteria that cause tooth decay, such as Streptococcus mutans (S. mutans), create a dense network of proteins and carbohydrates that block antibiotics from reaching the microbes. However, gold nanoparticles can overcome this obstacle due to their ability to convert light energy into heat, which is ideal for killing pathogens using photothermal therapy.
To further study this effect, the researchers placed gold spheres within larger cage-shaped nanoparticles made from gold to enhance their response to light, allowing the biofilms to be imaged and processed.
To attract the bacteria, the particles were coated with dextran, a carbohydrate commonly found in biofilms, and applied to the teeth of rats infected with S. mutans.
In the study, gold nanoparticles delivered to infected teeth and skin wounds were heated by near-infrared lasers to destroy biofilms.
During photoacoustic testing of teeth, the nanoparticles produced clear signals, allowing researchers to pinpoint where biofilms had absorbed dextran-coated particles on teeth. For comparison, the researchers treated other samples of infected teeth with the topical antiseptic chlorhexidine.
They found that photothermal therapy was almost completely successful in eliminating biofilms, while chlorhexidine had minimal effect on reducing bacterial viability.
Researchers were able to visualize biofilms on teeth treated with dextran-coated gold nanoparticles using photoacoustic imaging.
However, this study had limitations. Further tests are needed to determine whether this approach can prevent tooth decay or speed up the healing process.
“I think the most important thing is to understand how inexpensive, simple and fast this process is,” added Dr. Hadjfatalian. “Because we are limited in our use of antibiotics, we need new treatments like this as a replacement.”