In a major advancement in nanomedicine, nanorobots were programmed to target and destroy tumors.
Each nanorobot is made from a flat, rectangular DNA origami sheet that is 90 nanometres by 60 nanometres in size.
Once bound to the tumor blood vessel surface, the nanorobot was programmed to deliver its unsuspecting drug cargo in the very heart of the tumor, exposing an enzyme called thrombin that is key to blood clotting.
The treatment blocked blood supply to the tumor and generated tumor tissue damage within 24 hours while having no effect on healthy tissues.
After attacking tumors, most of the nanorobots were cleared and degraded from the body after 24 hours.
The median survival time is more than doubled, extending from 20.5 to 45 days.
"Moreover, this technology is a strategy that can be used for many types of cancer, since all solid tumor-feeding blood vessels are essentially the same," said Hao Yan, Professor and Director at Arizona State University, in a paper published in the journal Nature Biotechnology.
Until now, the challenge to advancing nanomedicine has been difficult because scientists wanted to design, build and carefully control nanorobots to actively seek and destroy cancerous tumors, while not harming any healthy cells.
However, the new "nanorobots can be programmed to transport molecular payloads and cause on-site tumor blood supply blockages, which can lead to tissue death and shrink the tumor", explained Baoquan Ding, Professor at the National Centre for Nanoscience and Technology (NCNST) in China.
For the study, the team used a melanoma mouse model, where the nanorobot not only affected the primary tumor but also prevented the formation of metastasis, showing promising therapeutic potential.
Importantly, the nanorobots were found safe and effective in shrinking tumors and there was no evidence of the nanorobots spreading into the brain where it could cause unwanted side-effects, such as a stroke.
"The thrombin delivery DNA nanorobot constitutes a major advance in the application of DNA nanotechnology for cancer therapy," Yan said.