. Their zinc-based nanomotor dissolved in the harsh stomach acids, producing hydrogen bubbles that rocketed the robot forwards. In the lower gastrointestinal tract, they instead use magnesium. “Magnesium reacts with water to give a hydrogen bubble,” says Wang. In either case, the metal micromotors are encapsulated in a coating that dissolves at the right location, freeing the micromotor to propel the bot into the mucous wall.
In the Netherlands, chemist Daniela Wilson at Radboud University in Nijmegen and colleagues have developed enzyme-driven nanomotors powered by DNA that might similarly be able to autonomously home in on tumour cells. The motors navigate towards areas that are richer in DNA, such as tumour cells that undergoing apoptosis.
Sánchez tells a similar story: while he began talking to physicians around a decade ago, their interest has warmed considerably since his experiments in animals began three to four years ago. “We are still in the lab, but at least we are working with human cells and human organoids, which is a step forward,” says his collaborator Vilaseca.
For example, Martin Pumera, a nanoroboticist at the University of Chemistry and Technology in Prague, is interested in improving dental care by landing nanobots beneath titanium tooth implants. The tiny gap between the metal implants and gum tissue is an ideal niche for bacterial biofilms to form, triggering infection and inflammation. When this happens, the implant must often be removed, the area cleaned, and a new implant installed — an expensive and painful procedure.