Researchers at the University of Waterloo are testing tiny, soft robots designed to dissolve certain kidney stones from inside the urinary tract.  

The centimeter-long flexible strips are fitted with movable magnets, which are positioned near uric acid kidney stones, using a robotic arm operated by doctors. The robot strips contain an enzyme called urease which reduces the acidity of the surrounding urine, with the aim of dissolving the stones until they become small enough to pass naturally. 

The approach has not yet been tested on animals or humans. Researchers say the next stage will involve large-animal studies, as well as improvements to the robots' magnetic control and the ultrasound imaging that would be used to guide them. 

Kidney stones affect roughly 12% of people and can recur. Treatment can include medication to help dissolve certain stones, pain management, or surgical procedures, depending on the type, size, and location of a stone and whether it is blocking urine flow. 

The Waterloo-led team included electrical and computer engineering professor Alfred Yu and mechanical and mechatronics engineering professor Mir Behrad Khamesee, along with collaborators from universities and hospitals in Spain and Germany. 

The findings were published in Advanced Healthcare Materials in a paper titled "Kidney Stone Dissolution By Tetherless, Enzyme-Loaded, Soft Magnetic Miniature Robots." 

The technology remains an early-stage research prototype. No human trials or clinical timelines have been announced.