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Programmed DNA Nanorobots Can Reduce Tumor

[Estimated read time: 4 minutes]
  • Molecule-sized nanoparticles can now destroy cancerous tumors by blocking their blood supply. 
  • The technology is demonstrated in mammals with breast cancer, ovarian, melanoma and lung-cancer mouse models. 
  • The nanorobots began damaging tumor within 24 hours after injection, leaving no negative effect on healthy tissues. 

Nanomedicine is a new field of medicine that utilizes the potentials of nanotechnology to open up new doors for treatments, for instance creating molecule-sized nanoparticles to diagnose and treat complex diseases like cancer.

The research has being going on for the last couple decades. Today, nanomedicine has come a long way. Tiny robots can be programmed and ejected into body to seek and modify particular cell. You can call them smart nano-sized robots (1000 times smaller than a human hair) that are specially designed to transport molecular payloads at targeted parts.

Recently, researchers at Arizona State University and National Center for Nanoscience and Technology have developed programmed nanorobot that can reduce the size of tumor by cutting off their blood supply. In special cases, this can even destroy tumors.

For the first time, they’ve built completely autonomous DNA robotic system for precise drug delivery and cancer therapy. Since most of the blood vessels feeding tumor are same, the technology can target several types of cancer.

How Does It Work?

Image credit: ASU Biodesign Institute

The scientists figured out a simple strategy to selectively pursue and starve out a tumor. They have been working on this for last 5 years. The idea is to use DNA-based nanocarriers to cut off the blood supply to tumor by inducing blood coagulation.

The nanorobots are now fully programmable and can perform mission entirely on its own. They can trigger blockage of tumor blood-supply, resulting in tumor-shrinkage and tissue death.

Scientists have demonstrated the technology in mammals with breast cancer, ovarian, melanoma and lung-cancer mouse models.

In order to perform this, scientists injected human cancer cells into a mouse model to induce tumor growth. Then they deployed nanorobots to reduce and kill this tumor.

Design of Nanorobots

Each nanorobot is made of rectangular, flat DNA origami sheet, 90*90 nm in size. Its surface was attached with thrombin (blood-clotting enzyme). Thrombin is responsible for blocking the flow of blood within the vessels that feed tumor-development. Thrombin causes a kind of tumor mild heart attack, resulting in tumor tissue death.

Image credit: ASU Biodesign Institute

They attached an average of 4 thrombin molecules to a DNA scaffold, and then folded this DNA sheet on itself, just like a paper sheet into a circle to create a hollow tube. They also examined the ability of DNA nanorobot to remain bound to surface nucleolin-positive cells.

Reference: Nature Biotechnology | doi:10.1038/nbt.4071 | Arizona State University

The nanorobots were programmed to attack only specific cells (cancer cell in this case). How exactly did they programmed, you asked? Well, they included an unusual payload, known as DNA aptamer, on the surface of the nanorobots. It could precisely target a protein, named nucleolin, which is found in excess on the surface of tumor endothelial cells (not on any healthy cell surface).

Image credit: ASU Biodesign Institute

Once the tumor surface is found, the nanorobots delivers drug cargo into the core of the tumor, exposing thrombin. Within few hours after injection, these nanorobots assembled themselves near tumor in a large quantity.

Positive Results

These nanorobots were safe and they didn’t have any side effects – no detectable alterations in cell morphology, normal blood coagulation and brain tissue. They were proved to be save in the normal tissues of mice as well as bigger animals.

The nanorobots began damaging tumor within 24 hours, leaving no negative effect on healthy tissues. In fact, 3 out of 8 mice in melanoma mouse model showed full regression of the tumors. The median survival time increased from 20.5 to 45 days.

Moreover, scientists tested the technology in mouse lung cancer model, and they found that the tumor tissue was reduced to a significant level after 2 weeks of treatment.

What’s Next?

Researchers plan to pursue clinical and hospital partners to advance their technology. There are several practical medical applications. In future, the technique can be combined with different types of nanorobots carrying multiple agents to accomplish their goal, like eradicate solid tumors and vascularize metastases.

Read: Electric Propulsion Technology For Nanorobots Is Now 100,000 Times Faster 

Moreover, the present method could be built as a drug-delivery system by configuring the geometry and structure of nanorobots and loaded cargoes, to treat other diseases as well.

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