Key Points:
- Nanorobots reduce tumor size by 30% when injected into the bloodstream and 70% when injected directly into tumors.
- The nanorobots exploit the differing properties between cancer cells and healthy cells to help prevent unwanted side effects.
Notwithstanding years of grave attempts, cancer’s cure has long evaded the grasp of modern medicine. A major hurdle has been generating therapies that kill cancer but not the rest of the body. Insofar as healthy organs look like cancer, it is difficult for drugs to discriminate between the two. However, tumors do not exhibit the same properties as healthy organs, which researchers at the Karolinska Institutet in Sweden have exploited.
Nanorobots vs Tumors
In a new study published in Nature Neurotechnology, Swedish scientists developed nanorobots capable of attacking cancer cells. Remarkably, by injecting the nanorobots into the bloodstream of tumor-implanted mice, there was a 30% reduction in tumor volume. Furthermore, when the nanorobots were injected directly into the tumor, there was a 70% reduction in tumor volume.
In Petri dish experiments, the researchers showed that the nanobots selectively attacked cancer cells while keeping healthy cells alive. Moreover, the authors say that the nanobots did not affect non-tumor cells in mice. These findings suggest that the nanobots can reduce the growth of tumors, especially upon direct injection, without harming healthy cells. However, the authors say that “future studies should investigate this in humanized mouse models for a more accurate assessment.”
How Do the Nanorobots Work?
The researchers employed what is called DNA origami — where DNA strands can be folded to generate specific shapes. They took six DNA strands, attached them to peptides — short strands of amino acids (the building blocks of proteins) — and arranged them to form a hexagon shape. The DNA strands were oriented so that, when unfolded, the peptides could bind to death receptors, the receptors on cells that cause them to die (apoptosis).
Cells within tumors are acidic, which means they have lower pH values than healthy cells. The researchers exploited this property and designed the nanorobots accordingly. Normally, the pH of our cells is strictly maintained at 7.4, while the pH of tumors is about 6.5. Therefore, they developed a nanorobotic switch that is turned on by a low pH level. This switch causes the DNA strands to fold upwards, revealing the peptides to cancer cells with a much higher probability than healthy cells.
The Future of Nanorobot Cancer Therapies
While the study shows that tumor growth can be stunted by nanorobots in mice implanted with tumors, more studies are needed to determine their efficacy in models more resembling human cancer. The study’s first author Yang Wang said,
“We now need to investigate whether this works in more advanced cancer models that more closely resemble the real human disease. We also need to find out what side effects the method has before it can be tested on humans.”
The key to the nanobots success is targeting only cancer cells. For this reason, researchers need to be sure that the nanorobots don’t kill healthy cells. If this can be shown repeatedly in more human-like models of cancer, then we may see the nanorobots being tested in humans. If successful in human trials, cancer-fighting nanorobots may revolutionize cancer therapy.
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