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Tuesday, November 30, 2010

The Beginning of the End of Cancer?

This Is the Future of the Fight Against Cancer 

A nanorobot is a tiny machine designed to perform a specific task or tasks repeatedly and with precision at nanoscale dimensions, that is, dimensions of a few nanometers (nm) or less. Nanorobots have potential applications in the assembly and maintenance of sophisticated systems. They might function at the atomic or molecular level to build devices, machines, or circuits, a process known as molecular manufacturing. Nanorobots might also produce copies of themselves to replace worn-out units, a process called self-replication.

A robot that measures only six atoms across, a nanorobot could have the ability to interact at the bacteria and virus level. A nanobots’ main function will probably be medical. They have the potential to revolutionize the medical community in almost every way. Nanorobots are so tiny that they could be easily injected into the bloodstream, where they would then navigate through the circulatory system in order to locate and fix problem areas of the body.

Don't be surprised if the world's first medical nanobot is sperm-propelled. Simply shrinking a design that swims well at the macroscale is no guarantee that it'll zoom along at the micro- or nanoscale.Once medicine has a nanoswimmer or nanocrawler (or have appropriated one from nature), researchers are going to have to figure out how to guide it towards a target and either release its payload or do whatever repairs need to be done. (S. Subramanian, J. S. Rathore, N. N. Sharma, "Design and Analysis of Helical Flagella Propelled Nanorobots," 2009 4th IEEE International Conference on Nano/Micro Engineered and Molecular Systems, 2009)
Here is a comparison. If you were to shrink, Fantastic Voyage-style and find yourself swimming in water, you'd think the water had turned into a highly viscious liquid like molasses. This has to do with the dynamics of fluids at different length scales. But, flagella is basically, a propeller for microbes.

Scientists in Israel created a microrobot only a few millimeters in length, which uses small appendages to grip and crawl through blood vessels. The scientists manipulate the arms by creating magnetic fields outside the patient's body. The magnetic fields cause the robot's arms to vibrate, pushing it further through the blood vessels. The scientists point out that because all of the energy for the nanorobot comes from an external source, there's no need for an internal power source. (Jonathan Strickland, "How Nanorobots Will Work,", October 11 2007)

Others believe miniaturized jet pumps could even use blood plasma to push a nanorobot forward, though, unlike the electromagnetic pump, there would need to be moving parts.

Nanorobots -- New Cancer Treatment

This Is the Future of the Fight Against Cancer

Feast your eyes closely on the photo above.You may be staring at the end of cancer. Those tiny black dots are nanobots delivering a lethal blow to a cancerous cell, effectively killing it. The first trial on humans has been a success, with no side-effects. ("This Is the Future of the Fight Against Cancer,"
"It sneaks in, evades the immune system, delivers the siRNA, and the disassembled components exit out."
Those are the words of Mark Davis, head of the research team that created the nanobot anti-cancer army at the California Institute of Technology. According to a study to be published in Nature, Davis' team has discovered a clean, safe way to deliver RNAi sequences to cancerous cells. RNAi (Ribonucleic acid interference) is a technique that attacks specific genes in malign cells, disabling functions inside and killing them.

More than a decade ago, Nobel Prize winners Andrew Fire and Craig Mello found that shutting down cancer genes was easier when using RNA interference. This method uses double-stranded small interfering RNA chains (siRNAs) to cut the messenger RNA cancer cells use to repliate, rather than the RNA or DNA itself.
Researchers Fire and Craig made their discovery in worms, though, and before now, no one had shown that the siRNAs could be introduced into humans and make their way to targeted cancer cells. (Nicholas Wade, "2 American 'Worm People' Win Nobel for RNA Work," The New York Times, October 3 2006)

Now, Davis, Ribas, and their team have the pictures to prove that they've used nanoparticles to deliver siRNAs directly to cancer cells and that the siRNAs have indeed interfered with the cancer cells' ability to multiply.

Advancement in Nobel Prize-winning technology can deliver targeted therapy directly to cancer tumor cells, says Davis. The clinical trial showed that a specialized polymer nanoparticle injected into patients' bloodstreams did indeed carry a genetic off-switch message to cancer cells, rendering their proteins unable to replicate. (Kimberly Hill, "Nanobots Flip Off  Cancer Calls at Switch," TechNewsWorld, March 23 2010)

The 70-nanometer attack bots—made with two polymers and a protein that attaches to the cancerous cell's surface—carry a piece of RNA called small-interfering RNA (siRNA), which deactivates the production of a protein, starving the malign cell to death. Once it has delivered its lethal blow, the nanoparticle breaks down into tiny pieces that get eliminated by the body in the urine.
The most amazing thing is that doctors can send as many of these soldiers as they want, and the warriors will keep attaching to the bad guys, killing them left, right, and center, and stopping tumors. According to Davis, "the more [they] put in, the more ends up where they are supposed to be, in tumour cells." While they will have to finish the trials to make sure that there are no side-effects whatsoever, the team is very happy with the successful results and it's excited about what's coming:
"What's so exciting is that virtually any gene can be targeted now. Every protein now is druggable. My hope is to make tumors melt away while maintaining a high quality of life for the patients. We're moving another step closer to being able to do that now."

If the studies continue to show promise, nanobots could be our best friends when it comes to cancer. We may be able to customize dosages based on cancer type, and they appear to leave good cells alone and work in conjunction with other treatments.

For example, researchers at Georgia Institute of Technology and the Ovarian Cancer Institute are also studying the use of siRNAs. Their method is to hide a nanoparticle with siRNAs inside of a hyrogel, which then sneaks its way inside cancer cells. Once inside, it kills the cells and helps make chemotherapy more effective. The researchers have even been able to time the release of siRNAs from the nanobots to get the most out of them. (Katherine Noyes, "Nanotech 'Trojan Horse' Sneaks Drugs Into Cancer Cells," TechNewsWorld, February 18 2010)

"We are on the brink of a new era in cancer treatment." 

--Mauro Ferrari, professor and chairman of the department of nanomedicine and biomedical engineer at the University of Texas

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