Spanish scientists successfully fought bladder cancer. They created nanorobots that feed on urea, penetrate cancer cells and destroy them with radioactive atoms.

Bladder cancer is one of the most common. It ranks fourth among the most common tumors in men. Despite relatively high survival, remission is short-lived in patients. Almost half of bladder tumors recur within five years of recovery.

Patients need constant medical examinations and repeated drug treatments, placing a financial burden on the healthcare system. This type of cancer is one of the most expensive to treat and often involves direct injection of immunotherapeutic and/or chemotherapy drugs into the bladder.

Modern treatment methods have side effects and do not always help to finally defeat bladder cancer, as statistics on cases of recurrence of the disease show. A promising alternative to this type of treatment are nanorobots (nanoparticles) that can deliver active substances directly to the tumor. Nanomachines that can move independently within the body are of particular interest.

Such “biological devices” were created by a group of Spanish biochemists from the Bioengineering Institute of Catalonia, the Barcelona Biomedicine Institute and the Autonomous University of Barcelona. Scientists described this in an article published in the journal Nature Nanotechnology .

Nanorobots are spherical structures with silicon pores, 450 nanometers in diameter, containing the artificial radioactive isotope of iodine – iodine-131. Doctors use this isotope to destroy cancer cells in some types of tumors. The surface of the biomachines is covered with various components, including gold nanoparticles and molecules of urease, an enzyme that breaks down urea with the formation of ammonia and carbon dioxide.

The latter plays the role of the “engine” of the nanomachine. The enzyme interacts with urea molecules, which enable the tiny machines to move. The nanorobots then deliver their contents directly to the cancer cells where the drugs accumulate. As a result, the therapeutic effect is distributed evenly throughout the bladder, which is a major problem for current anticancer drugs.

Spanish biochemists first tested their technology on bladder cancer cell cultures and, a little later, on laboratory mice injected with nanorobots. Observations in rodents, including positron emission tomography and microphotographs of tissues, showed that the nanoparticles continuously passed through the mice’s bladder and actively penetrated the tumor.

“With the help of a single dose of nanoparticles, we achieved a 90 percent reduction in tumor volume in rodents. Important: without visible harm to the rest of the animal’s body. Usually patients with this type of cancer need six to 14 procedures to achieve a positive effect. Simply put “Our nanorobots could revolutionize the treatment of bladder cancer, shorten hospital stays and reduce treatment costs. But above all, human trials are needed,” said Samuel Sanchez, one of the study’s authors.

Why do nanoparticles penetrate cancer cells? According to the researchers, this has to do with the structure of the neoplasms inside the bladder – they are spongy and loose, making it easy for nanorobots to penetrate their thickness. The Spanish scientists’ next step is to understand whether cancer in rodents will relapse after being treated with nanoparticles.