IISc develops nanobots to deep clean teeth

The Indian Institute of Science (IISc) in Bengaluru on Monday said that it had developed nano-sized robots capable of killing bacteria deep inside dentinal tubules, and boosting the success of root canal treatments,

“The dentinal tubules are very small, and bacteria reside deep in the tissue. Current techniques are not efficient enough to go all the way inside and kill the bacteria,” Shanmukh Srinivas, research associate at the Centre for Nano Science and Engineering (CeNSE), IISc, and co-founder of Theranautilus said. Theranautilus is a startup incubated by the IISc.

The researchers said that root canal treatments are routinely carried out to treat tooth infections in millions of patients and the procedure involves removing the infected soft tissue inside the tooth, called the pulp, and flushing the tooth with antibiotics or chemicals to kill the bacteria that cause the infection.

“But many times, the treatment fails to completely remove all the bacteria – especially antibiotic-resistant bacteria such as Enterococcus faecalis – which remain hidden inside microscopic canals in the tooth called dentinal tubules,” according to IISc.

The study has been published in Advanced Healthcare Materials. The nanobots are manipulated using a magnetic field and researchers designed helical nanobots made of silicon dioxide coated with iron, which can be controlled using a device that generates a low-intensity magnetic field.

The researchers added that by tweaking the frequency of the magnetic field, they were able to make the nanobots move at will, and penetrate deep inside the dentinal tubules. “We have also established that we can retrieve them … we can pull them back out of the patient’s teeth,” said Srinivas.

“Crucially, the team was able to manipulate the magnetic field to make the surface of the nanobots generate heat, which can kill the bacteria nearby. “No other technology in the market can do this right now,” Debayan Dasgupta, Research Associate at CeNSE and co-founder of Theranautilus, said.

The research and its findings add more teeth to existing technology to help dental health professionals.

Earlier, scientists used ultrasound or laser pulses to create shockwaves in the fluid used to flush out bacteria and tissue debris, to improve the efficiency of root canal treatment.

“But these pulses can only penetrate up to a distance of 800 micrometres, and their energy dissipates fast. The nanobots were able to penetrate much further – up to 2,000 micrometres. Using heat to kill the bacteria also provides a safer alternative to harsh chemicals or antibiotics,” the researchers said.

They added that their research has shown that such nanoparticles can trap and move objects using light, swim through blood and inside living cells, and stick strongly to cancer cells. “These studies have shown that they are safe to use in biological tissues,” says Dasgupta.

The team has tested the dental nanobots in mice models and found them to be safe and effective. They are also working on developing a new kind of medical device that can easily fit inside the mouth, and allow the dentist to inject and manipulate the nanobots inside the teeth during root canal treatment, they added.