Nanobots? Or Surface Chemistry? Kills Cancer Tumors

While I find calling it “Nanorobots” is a bit much (to me it looks more like sheet surface chemistry) that it kills cancer tumors is still a great step forward.

Basic idea is a DNA sheet that gets clotting agent applied to one side, then allowed to roll up around them. This protects the “payload” from being active in the general body context. When it encounters a particular protein on the lining of blood vessels of tumors (that is not present in normal blood vessels) the outside adheres to it causing it to unroll and expose the clotting agent. This causes a blood clot that cut off blood to the solid tumor.

VERY nifty and VERY well done chemistry. Not seeing anything mechanical nor electrical in it causes me to not see anything I’d call a “robot”, so doubting the name of “nanorobot” for it. Polymer physical chemistry is more like it; but hey, guess they needed to hype it somehow.

https://www.sciencedaily.com/releases/2018/02/180212112000.htm

Cancer-fighting nanorobots programmed to seek and destroy tumors
Study shows first applications of DNA origami for nanomedicine

Date:
February 12, 2018
Source:
Arizona State University
Summary:
In a major advancement in nanomedicine, scientists have successfully programmed nanorobots to shrink tumors by cutting off their blood supply.

In a major advancement in nanomedicine, Arizona State University (ASU) scientists, in collaboration with researchers from the National Center for Nanoscience and Technology (NCNST), of the Chinese Academy of Sciences, have successfully programmed nanorobots to shrink tumors 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 tumor-feeding blood vessels are essentially the same,” said Yan.

The successful demonstration of the technology, the first-of-its-kind study in mammals utilizing breast cancer, melanoma, ovarian and lung cancer mouse models, was published in the journal Nature Biotechnology.
[…]
Each nanorobot is made from a flat, rectangular DNA origami sheet, 90 nanometers by 60 nanometers in size. A key blood-clotting enzyme, called thrombin, is attached to the surface.

Thrombin can block tumor blood flow by clotting the blood within the vessels that feed tumor growth, causing a sort of tumor mini-heart attack, and leading to tumor tissue death.

First, an average of four thrombin molecules was attached to a flat DNA scaffold. Next, the flat sheet was folded in on itself like a sheet of paper into a circle to make a hollow tube.

They were injected with an IV into a mouse, then traveled throughout the bloodstream, homing in on the tumors.

The key to programming a nanorobot that only attacks a cancer cell was to include a special payload on its surface, called a DNA aptamer. The DNA aptamer could specifically target a protein, called nucleolin, that is made in high amounts only on the surface of tumor endothelial cells — and not found on the surface of healthy cells.

Once bound to the tumor blood vessel surface, the nanorobot was programmed, like the notorious Trojan horse, 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 nanorobots are decidedly safe in the normal tissues of mice and large animals,” said Guangjun Nie, another professor at the NCNST and a key member of the collaborative team.

The treatment blocked tumor blood supply 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.

By two days, there was evidence of advanced thrombosis, and 3 days, thrombi in all tumor vessels were observed.

Heck of an advance. Hope it gets to the approved drug stage quickly. But I’m not calling it robots ;-)

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