PREVIEW

Scientists have a new tool in the fight against cancer - nanorobots.
A study published in the prestigious journal Nature Nanotechnology reveals how a research team successfully reduced the size of bladder tumours in mice by 90% through a single dose of urea-powered nanorobots.
These tiny nanomachines consist of a porous sphere made of silica. Their surfaces carry various 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 research, led by the Institute for Bioengineering of Catalonia (IBEC) and CIC biomaGUNE in collaboration with the Institute for Research in Biomedicine (IRB Barcelona) and the Autonomous University of Barcelona (UAB), paves the way for innovative bladder cancer treatments.
"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 6 to 14 hospital appointments with current treatments. Such a treatment approach would enhance efficiency, reducing the length of hospitalization and treatment costs," explains Samuel Sánchez, ICREA research professor at IBEC and leader of the study.
In previous research, the scientists confirmed that the self-propulsion capacity of nanorobots allowed them to reach all bladder walls.
This new study goes further by demonstrating not only the mobility of nanoparticles in the bladder but also their specific accumulation in the tumour. This achievement was made possible by various techniques, including medical positron emission tomography (PET) imaging of the mice, as well as microscopy images of the tissues removed after completion of the study. The latter were captured using a fluorescence microscopy system developed specifically for this project at IRB Barcelona. The system scans the different layers of the bladder and provides a 3D reconstruction, thereby enabling observation of the entire organ.
"The innovative optical system that we have developed enabled us to eliminate the light reflected by the tumour itself, allowing us to identify and locate nanoparticles throughout the organ without prior labelling, at an unprecedented resolution. We observed that the nanorobots not only reached the tumour but also entered it, thereby enhancing the action of the radiopharmaceutical," explains Julien Colombelli, leader of the Advanced Digital Microscopy platform at IRB Barcelona.
Deciphering why nanorobots can enter the tumour posed a challenge. Nanorobots lack specific antibodies to recognise the tumour, and tumour tissue is typically stiffer than healthy tissue.
"However, we observed that these nanorobots can break down the extracellular matrix of the tumour by locally increasing the pH through a self-propelling chemical reaction. This phenomenon favoured greater tumour penetration and was beneficial in achieving preferential accumulation in the tumour," explains Meritxell Serra Casablancas, co-first author of the study and IBEC researcher.
Thus, the scientists concluded that the nanorobots collide with the urothelium as if it were a wall, but in the tumour, which is spongier, they penetrate the tumour and accumulate inside. A key factor is the mobility of the nanobots, which increases the likelihood of reaching the tumour.
Cristina Simó, co-first author of the study says the new research could open the door to a whole new frontier in the fight against cancer.
"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," she adds.
The technology underlying these nanorobots, which Samuel Sánchez and his team have been developing for over seven years, has recently been patented and serves as the foundation for Nanobots Therapeutics, a spin-off of IBEC and ICREA established in January 2023.