Self-Propelling Nanorobots Reduce Bladder Tumors by 90%

It has a high recurrence rate, with about half of the cases recurring within five years, creating the need for continuous monitoring. This constant need for follow-up and repeated treatments makes bladder cancer treatment one of the costliest. While current treatments, which involve administering drugs directly into the bladder, offer favorable survival rates, their therapeutic effectiveness is still limited. An emerging and promising approach is the use of nanoparticles, particularly nanorobots, that can self-propel and deliver therapeutic agents directly to cancer cells.

A recent breakthrough by scientists at IRB Barcelona (Barcelona, Spain) has demonstrated the potential of urea-powered nanorobots in bladder cancer treatment. In their study, the team achieved a significant 90% reduction in bladder tumor size in mice using a single dose administered by these nanorobots. The nanorobots are essentially tiny machines, composed of porous silica spheres. Their surfaces are equipped with various components, each serving a specific purpose. One key component is the enzyme urease, which reacts with urea in urine, propelling the nanorobot forward. Another crucial element is radioactive iodine, widely used in localized tumor treatment.

Understanding how these nanorobots penetrate the tumor was challenging, as they do not possess specific antibodies for tumor recognition and because tumor tissue is generally stiffer than healthy tissue. However, the team discovered that the nanorobots could break down the tumor's extracellular matrix by locally increasing pH through their self-propelling action. This action enhances their penetration into and accumulation within the tumor. The researchers observed that while the nanorobots collide with the urothelium, acting as if they hit a wall, they effectively penetrate and accumulate inside the spongier tumor tissue.

The mobility of these nanobots significantly increases their chances of reaching and impacting the tumor. Additionally, the localized delivery of these nanorobots, carrying the radioisotope, reduces potential side effects. The high accumulation of these nanorobots in tumor tissue also intensifies the radiotherapeutic impact. This research offers promising directions for bladder cancer treatment, potentially reducing hospital stays, lowering costs, and improving patient comfort. The next research phase is already in progress, focusing on whether tumors recur post-treatment with these nanorobots.

"With a single dose, we observed a 90% decrease in tumor volume. This is significantly more efficient given that patients with this type of tumor typically have 6 to 14 hospital appointments with current treatments," said Samuel Sánchez, ICREA research professor at IBEC and leader of the study. “Such a treatment approach would enhance efficiency, reducing the length of hospitalization and treatment costs.”

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