Researchers have been exploring the use of injectable nanoparticles that can quickly home in on a microscopic tumor. It’s a novel technique that could pave the way for the early detection of small tumors that may not show up on traditional imaging technologies. In a study published in the October issue of the IEEE Internet of Things Journal, one team has found a way to guide cancer-detecting nanoparticles to a tumor faster, while using fewer resources.

An estimated 13 million people worldwide may die from cancer in 2023, according to the World Health Organization. One key way to reduce the mortality rate is through early detection of the disease, yet existing medical imaging techniques offer limited resolution when it comes to detecting microscopic tumors less than 0.5 millimeters in diameter.

“The rise of nanotechnologies provides a strong hope to solve this problem, where the small sizes of nanoparticles enable them to leak out of blood vessels and accumulate within tumors,” explains Yifan Chen, a professor at the University of Electronic Science and Technology of China, in Chengdu.

However, it can be difficult to develop these “nanoswimmers,” which can efficiently disperse throughout a patient’s body, while sufficiently accumulating at the cancer site. Past studies show that only 0.7 percent of the injected nanoparticles reach their target.

There are two solutions to help nanoswimmers better target tumors. The first is to guide them to a suspected cancer site using a magnetic field applied outside the patient’s body. This approach helps the particles move relatively quickly through the body—but requires a lot of oversight, as the nanoswimmers must be continuously monitored and guided throughout the process. 

Another option is to develop self-propelled nanoswimmers, which autonomously move inside the human body and have a chemical tendency to accumulate in tumors. For example, nanoswimmers designed to gravitate toward acidic environments will gravitate toward tumors, which tend to be more acidic than healthy tissues. But, autonomous nanoswimmers tend to move much slower than the magnetically guided nanoswimmers.

Chen’s solution is to combine the advantages of each approach, for a more efficient way to target tumors. His team is proposing a fleet of semi-autonomous nanoswimmers that begin to gravitate toward cancer. In their theoretical scenario, the speed and aggregation pattern of the entire swarm is occasionally measured to see a general pattern of where the nanoswimmers are converging. Using this information, the semi-autonomous swarm can then be magnetically guided more quickly in the optimal direction: toward the tumor.

In their study, the researchers use simulations to show that this “spot sampling technique” provides sufficiently precise data to steer the semi-autonomous swarm toward the target using 90 percent fewer monitoring resources.

“Our studies have demonstrated that a hundredfold increase in the targeting efficiency can be achieved by using [our semi-autonomous approach] compared to techniques where nonautonomous nanoparticles are injected into the body with zero guidance,” says Chen.

While magnetically guided nanoswimmers already exist, Chen’s group is working on developing the semi-autonomous fleet. “We foresee that commercialization of the technology will happen in the next three to five years after completion of proof-of-concept animal experiments,” Chen says, noting his team has filed several patents. “We are also in the process of communicating with several med-tech companies in China for commercialization plans.”