Scientists Revolutionize Liver Cancer Treatment with Magnetic Microrobots

In an exciting development from Canada, Dr Gilles Soulez and his team have unveiled a revolutionary technique to change how liver tumours are treated. This cutting-edge method involves tiny, magnetically steerable microrobots within an MRI machine, offering a fresh perspective on medical treatments.

For years, the idea of employing minuscule robots to aid in healing within the human body has been a topic of fascination. These aren't just figments of science fiction; they are authentic, tiny, biocompatible machines made from magnetisable iron oxide nanoparticles. The beauty of these microrobots lies in their ability to be directed by external magnetic fields, allowing for targeted treatment delivery.

One of the main obstacles encountered in the past was the issue of gravity overpowering the magnetic forces intended to guide these robots. This was particularly problematic when reaching tumours above the injection site in the bloodstream. Despite the powerful magnetic fields generated by MRI machines, the gradients needed for navigation and imaging were insufficiently robust.

Dr. Soulez, who is associated with the CHUM Research Center and leads the Department of Radiology, radio-oncology, and Nuclear Medicine at the Université de Montréal, shared his team’s innovative solution to overcome this hurdle. "To solve this problem, we developed an algorithm that determines the position that the patient's body should be in for a clinical MRI to take advantage of gravity and combine it with the magnetic navigation force," he explained. This strategic approach helps direct the microrobots to the arterial branches feeding the tumour, improving the precision of treatment delivery.

The new technique signifies a shift in interventional radiology practices for treating liver cancer. Hepatocellular carcinoma, a common type of liver cancer, causes around 700,000 deaths annually worldwide. Traditionally, treatment involves transarterial chemoembolisation, a complex process where chemotherapy is directly delivered to the liver tumour's feeding artery, and the tumour's blood supply is blocked using microcatheters under X-ray guidance.

Dr. Soulez noted the benefits of magnetic resonance navigation, noting its compatibility with the implantable catheters used in chemotherapy. He emphasised the advantage of MRI over X-ray imaging in tumour visualisation, suggesting significant potential for this method in clinical applications.

The research team's collaboration with Sylvain Martel from Polytechnique Montreal and Urs O. Häfeli from the University of British Columbia has been pivotal in advancing this field. Ning Li, a postdoctoral fellow in Dr Soulez's laboratory and the study's first author, played a vital role in the research.

A key innovation was the development of an MRI-compatible microrobot injector, which assembles "particle trains"—clusters of these magnetisable microrobots that exhibit increased magnetic force, making them easier to navigate and detect in MRI scans.

To ensure the method's efficacy, the team conducted trials on 12 pigs, aiming to replicate human anatomical conditions as closely as possible. These trials confirmed the microrobots' capability to navigate to specific hepatic artery branches and reach their intended destinations, as the newly developed algorithm directed.

Additionally, the team utilised an anatomical atlas of human livers to simulate microrobot navigation in 19 patients previously treated with transarterial chemoembolisation, encompassing thirty tumours in different parts of the liver. The simulations indicated that the navigation algorithm was effective in over 95% of cases, allowing the microrobots to reach the targeted tumours successfully.

Despite these promising results, Dr. Soulez cautioned that the clinical adoption of this technology is still some way off. The following steps involve refining the real-time navigation of the microrobots using artificial intelligence, which would entail tracking the microrobots' location within the liver and identifying blockages in the hepatic artery branches that supply the tumour.

The team also develops models to simulate blood flow, patient positioning, and magnetic field direction. These models, created with fluid flow simulation software, will help determine how these factors affect the microrobots' journey to the tumour, thereby improving the treatment's accuracy and effectiveness.

This breakthrough by Dr. Soulez and his team represents a transformative approach to treating liver cancer, employing magnetically controlled microrobots to deliver therapy with unparalleled precision. By ingeniously merging gravitational and magnetic forces through a unique algorithm, this method promises increased treatment efficacy while minimising harm to healthy cells. However, the journey to clinical practice requires further advancements, particularly in the real-time navigation of the microrobots, which the team hopes to achieve with the help of artificial intelligence.