Tiny nanorobots that can self-propel within the body can reduce the size of bladder tumours by 90%, a study has shown.
Such nanorobots can deliver radioactive iodine directly to tumours inside the body, using urea (waste) as 'fuel'.
The research, which was conducted using mice, provides hope to patients with a bladder tumour, which has one of the highest incidence rates in the world and ranks as the fourth most common tumour in men.
Samuel Sanchez, ICREA research professor at Institute for Bioengineering of Catalonia in Spain and leader of the study, said: "With a single dose, we observed a 90% decrease in tumour volume. This is significantly more efficient given that patients with this type of tumour typically have six to 14 hospital appointments with current treatments.
"Such a treatment approach would enhance efficiency, reducing the length of hospitalisation and treatment costs."
How do the nanorobots work?
The tiny nanomachines consist of a porous sphere made of silica.
Their surfaces carry various chemical components with specific functions. Among them is the enzyme urease, a protein that reacts with urea found in urine, enabling the nanoparticle to propel itself.
Another crucial component is radioactive iodine, a radioisotope commonly used for the localised treatment of tumours. The robots 'swim' through the bladder until they encounter either the wall of the bladder or a tumour.
Why can they help kill tumours?
The scientists concluded that the nanorobots collide with the edge of the bladder as if it were a wall. In the tumour, which is spongier, they penetrate the tumour and accumulate inside.
The highly mobile nanobots swim everywhere until they encounter tumours. The next step, which is already underway, is to determine whether these tumours recur after treatment.
Why is this research important?
The finding that the nanorobots can accumulate in the tumours could hold out hope for further treatments, the researchers believe.
Jordi Llop, a researcher at CIC biomaGUNE in Spain and co-leader of the study, said: "The localised administration of the nanorobots carrying the radioisotope reduces the probability of generating adverse effects, and the high accumulation in the tumour tissue favours the radiotherapeutic effect."
Such nanorobots could be used to carry more powerful radioactive materials to deal with tumours, the researchers said.
Cristina Simo, co-first author of the research, said: "The results of this study open the door to the use of other radioisotopes with a greater capacity to induce therapeutic effects but whose use is restricted when administered systemically."