IIT-Kharagpur alumnus and his team incubated a start-up that kill bacteria deep inside dentinal tubules with nano-sized robot – Times of India

Root canal treatments are routinely carried out to treat tooth infections in millions of patients. 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.

In the study published in Advanced Healthcare Materials, the 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. These nanobots are then injected into extracted tooth samples and their movement is tracked using a microscope.
By tweaking the frequency of the magnetic field, the researchers were able to make the nanobots move at will, and penetrate deep inside the dentinal tubules.

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,” said Debayan Dasgupta, Research Associate at Centre for Nano Science and Engineering (CeNSE), IISc and a co-founder of Theranautilus.

Previously, scientists used ultrasound or laser pulses to create shockwaves in the fluid used to flush out bacteria and tissue debris, in order to improve the efficiency of root canal treatment. But these pulses may only penetrate up to a distance of 800 micrometers and their energy dissipates fast. The nanobots are able to penetrate much further – up to 2,000 micrometers. Using heat to kill the bacteria also provides a safer alternative to harsh chemicals or antibiotics, the researchers said.

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.

As Professor Ghosh said, “We are very close to deploying this technology in a clinical setting, which was considered futuristic even three years ago. It is a joy to see how a simple scientific curiosity is shaping into a medical intervention that can impact millions of people in India alone.”

Professor Ambarish Ghosh, of the Department of Physics of the Indian Institute of Science (IISc), Bangalore had done a five-year Integrated MSc in Physics from the Indian Institute of Technology (IIT), Kharagpur in 1997. He also did Ph.D. in physics in 2004 from Brown University, Providence, RI, USA and was a Postdoctoral fellow at Harvard University, USA from 2005 to 2009.