Image Credit: Jason Drees, Arizona State University
A team of researchers from Arizona State University (ASU), in partnership with the Chinese Academy of Sciences’ National Center for Nanoscience and Technology (NCNST), have developed nanorobots smaller than a human hair which can shrink and destroy cancer tumours by cutting off their blood supply.
“We have developed the first fully autonomous, DNA robotic system for a very precise drug design and targeted cancer therapy,” said Hao Yan, Director of the ASU Biodesign Institute’s Center for Molecular Design and Biomimetics and the Milton Glick Professor in the School of Molecular Sciences. “Moreover, this technology is a strategy that can be used for many types of cancer, since all solid tumour-feeding blood vessels are essentially the same.”
The team recently proved the technology’s effectiveness in a first-of-its-kind study with mouse models of breast, lung, and ovarian cancer and melanoma. After injecting human cancer cells into the mice to induce aggressive tumour growth, the team deployed nanorobots via IV injection, each measuring just 60 nanometers by 90 nanometers and with the blood-clotting enzyme thrombin attached to its surface. The thrombin acts to clot the blood flow within the tumour’s vessels, halting growth and leading to tissue death.
The study showed the technology to be safe and effective: tumour tissue damage was observed within 24 hours of injection with no effect on healthy cells, with evidence of advanced thrombosis after two days, and thrombi in all tumour vessels by day three. There was also no evidence of the nanorobots spreading to the brain where they could cause strokes and other unwanted side-effects.
“The nanorobot proved to be safe and immunologically inert for use in normal mice and, also in Bama miniature pigs, showing no detectable changes in normal blood coagulation or cell morphology,” said Yuliang Zhao, a professor at NCNST and lead scientist of the international collaborative team.
In the melanoma model, three of the eight mice receiving the therapy achieved complete tumour regression, while the median survival time more than doubled to 45 days from 20.5.
With their job done, the nanorobots degrade and are cleared from the body after 24 hours.
“The thrombin delivery DNA nanorobot constitutes a major advance in the application of DNA nanotechnology for cancer therapy,” said Yan. “In a melanoma mouse model, the nanorobot not only affected the primary tumour but also prevented the formation of metastasis, showing promising therapeutic potential.