Antimicrobial microrobots remove biofilms
Magnetic microrobots could offer an alternative to antibacterial drugs as a way of destroying biofilms on hard-to-reach surfaces of the tooth.
Biologists at the University of Pennsylvania partnered with dentists and engineers to design the microbots, which contain iron-oxide nanoparticles and are controlled via a rotating magnetic field.
[caption id="attachment_92068" align="alignleft" width="202"] Biofilms are layers of microorganisms that stick to wet surfaces. When they form on human teeth as plaque, they can become hard to remove with conventional dental apparatus once calcified.[/caption]
Hyun Koo of the School of Dental Medicine said: "Existing treatments for biofilms are ineffective because they are incapable of simultaneously degrading the protective matrix, killing the embedded bacteria, and physically removing the biodegraded products.
"These robots can do all three at once very effectively, leaving no trace of biofilm whatsoever," he said.
The team designed and tested two types of microrobots, which were no larger than 10mm in length and 5mm in diameter; the smallest measured about 1mm, capable of fitting inside the tooth.
The first involved suspending iron-oxide nanoparticles in a solution that can be directed by magnets, which removed the biofilm in a “plow-like” manner.
The second involved embedding nanoparticles into hydrogel moulds, which were used to destroy biofilms clogging enclosed tubes. The devices were found to be able to remove bacterial biofilms from the isthmus, a narrow corridor between root canals.
Treating biofilms on teeth can involve manual scraping, which lacks precision. Biofilms also show increased tolerance to antibiotics and disinfectant chemicals, highlighting the need for new cleaning technologies.
“This is important to other biomedical fields facing drug-resistant biofilms as we approach a post-antibiotic era,” Koo said.
Outside of dentistry, these robotic biofilm-removal systems could also keep water pies and catheters clean.
To move their solution to clinical application, the researchers are receiving support from the Penn Center for Health, Devices and Technology, which supports the creation of new health technologies. The solution was published in Science Robotics.