The collective movement of nanorobots observed in vivo

Nanobots are machines whose components are on the nano-scale (one millionth of a millimeter), and can be designed so that they have the ability to move independently in liquids. Although still in the research and development phase, significant progress is being made with the use of nanorobots in biomedicine. Their applications are diverse, from the identification of tumor cells to the release of drugs at specific locations of the body. Catalytic-powered nanorobots are one of the most promising systems because they are fully biocompatible and can use ‘fuels’ already available in the body for their propulsion. However, understanding the collective behavior of these nanorobots is essential to promote their use in clinical practice.

Now, in a new study published in the journal Science Robotics, researchers led by ICREA research professor Samuel Sánchez and his team “Smart Nano-Bio-Devices” at the Institute of Bioengineering in Catalonia (IBEC), together with the group Radiochemistry & Nuclear Imaging Lab of CIC biomaGUNE led by Jordi Llop and the Universitat Autònoma de Barcelona (UAB), has succeeded in observing the collective behavior of a large number of autonomous nanorobots in the vesicles of live mice in vivo using radioactive isotope labeling.

“The fact that we were able to see nanorobots move like a swarm together and follow them within a living organism is important because millions of them are needed to treat specific pathologies, such as cancerous tumors,” says Samuel Sánchez, principal investigator at IBEC.

“We have shown for the first time that nanorobots can be monitored in vivo by Positron Emission Tomography (PET), a very sensitive, non-invasive technique used in the biomedical environment,” said Jordi Llop, principal investigator at Radiochemistry & Nuclear Imaging. Laboratory of CIC biomaGUNE.

To do this, the researchers first performed in vitro experiments and monitored the nanorobots using optical microscopy and positron emission tomography (PET). Both techniques enabled them to observe how the nanoparticles mixed with the liquids and were able to migrate together and follow complex paths. The nanorobots are then administered intravenously to mice and eventually brought into the bladder of these animals. Since nanorobots are covered with an enzyme called urease, which uses the urea from urine as fuel, they swim together and cause fluids inside the bladder.

Collective movements similar to flocks of birds or fish

The team of scientists found that the distribution of nano-devices in the bladder of the mice was homogeneous, indicating that the collective movement was coordinated and efficient. “Nanorobots show collective movements similar to those found in the wild, such as birds flying in herds, or the orderly patterns that fish follow fish,” explains Samuel Sánchez, ICREA research professor at IBEC. “We have seen that nanorobots with surface urease move much faster than those that are not. This is therefore proof of the concept of the initial theory that nanorobots will be able to reach a tumor better and penetrate it,” says Jordi Llop, principal investigator at CIC biomaGUNE.

This study demonstrates the high efficiency of millions of nanoscopic devices to move in a coordinated manner in both in vitro and in vivo environments, a fact that is a fundamental advancement in the race of nanorobots around the key players in highly precise therapies. and to become treatments. Future applications in the medicine of these devices on a nano-scale are promising. It has also been demonstrated “that the motion of these devices can be monitored using imaging techniques that can be applied to the in vivo environment, in other words, it can be applied in experimental animals and offers the potential to transmit to humans, “says Cristina Simó, one of the first authors of the study and a researcher in the CIC biomaGUNE group.

“This is the first time that we can directly visualize the active distribution of biocompatible nanorobots within biological fluids in vivo. The ability to monitor their activity in the body and the fact that they show a more homogeneous distribution can revolutionize in the way we understand nanoparticle-based drug delivery and diagnostic approaches, “says Tania Patiño, co-author of the article.

Nanobot swarms can be especially useful in viscous media, where distribution of drugs is often limited by poor vascularization, such as in the digestive tract, the eye, or the joints. ‘In fact, since different enzymes can be incorporated into small cars, nanorobots can be adapted according to the part within the organism, which can adapt the device to the accessible fuel in the environment to which it must move’, concludes Professor Sánchez off.