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Print 27 comment(s) - last by tmouse.. on Dec 12 at 2:45 PM

Another iteration of the carbon nanotube versus the biological insurgent from Rensselaer Polytechnic Institute.

Ravi S. Kane, professor of chemical and biological engineering, and his team at Rensselaer Polytechnic Institute have devised a way to target harmful agents in the body and neutralize them without physical or chemical intervention. Kane’s method is similar to similar to other remote control cancer killers and uses the widely popular carbon nanotube (CNT) as the bomb.

Using various tuned peptides attached to the CNT as homing devices, the microscopic particles can seek out a programmed protein, such as anthrax toxin or cancer cells. Since the peptide coating on the CNT can be changed, groups of different neutralizers can be used in the same application without adversely affecting any other proteins.

Rather than using a microwave pulse, the Rensselaer method uses near-infrared light to act as a catalyst, activating the neutralizing agent. Different coatings can be made to respond to different frequencies of light, thus the same batch of CNTs could be used on several different toxins, drugs, or cells simultaneously. One type can be targeted specifically by using a single wavelength of light to which that neutralizer responds.

When the invisible, harmless light is shined on the CNTs that have found a target protein, they release free radicals called reactive oxygen species. These free radicals deactivate the target protein, rendering it harmless.

Kane's technique uses virtually no invasive methods and has other applications apart from a blood-borne detoxicant. His team has already developed a film that uses the nanotubes. "The ability of these coatings to generate reactive oxygen species upon exposure to light might allow these coatings to kill any bacteria that have attached to them. You could use these transparent coatings on countertops, doorknobs, in hospitals or airplanes -- essentially any surface, inside or outside, that might be exposed to harmful contaminants," Kane explained.

The method could also be used as a way to destroy toxins and pathogens in laboratories, saving money and man hours on hazardous biological disposal processes.



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RE: Resistance be gone
By tmouse on 12/11/2007 11:43:20 AM , Rating: 6
Well, yes and no; if any of the bacteria in question have a mutant peptide the nano-bomb will not be able to attach to it. You can of course choose a more ubiquitous protein but they may be shared with other beneficial bacteria or endogenous cells. The same thing goes for cancer. Monoclonal antibodies coupled to toxins have been around for quite a while, however after decades of looking VERY few unique proteins are on the surface of tumor cells; this is why they escape immune surveillance in the first place.


RE: Resistance be gone
By jtemplin on 12/11/2007 11:46:23 AM , Rating: 2
Another dream of panacea shot down : ) Thanks for the info. That makes perfect sense. I guess there is always a tradeoff with specificity and detection.


RE: Resistance be gone
By Christopher1 on 12/12/2007 2:02:16 AM , Rating: 1
Actually, this could still be a panacea. With all due respect to the poster before the posting I am commenting on..... a 'mutant peptide' would not keep the nanobots from destroying the bacteria.... they would just have to be programmed to find a way around it, if that is even a real thing... I'll have to look on Wikipedia and in the biological chemistry books I have lying around from my parents work.


RE: Resistance be gone
By tmouse on 12/12/2007 2:13:50 PM , Rating: 2
What I was trying to say is the nanotube must be coupled to either a monoclonal antibody or a ligand for a cell surface receptor. Its not about the killing in this case they use the nanotube to generate free radicals which is quite clever, but the problem still lies in the "targeting", a mutant peptide may not be recognized. The specificity of the targeting is both the strength and the weakness. Its very interesting work and it will have implications but it is not a panacea (I personally do not believe there will ever be a cure all and I have been working in the area for a long time)


RE: Resistance be gone
By Orbs on 12/11/2007 4:27:00 PM , Rating: 2
What about below the surface of tumor cells? Are there indicators within the cells themselves that could be used?

Light may not be a sufficient catalyst if the cells are opaque, but other methods (such as the microwave methods mentioned earlier in the year, or perhaps audio waves...) might be able to succeed the same way, if the right cells could be identified.


RE: Resistance be gone
By Pandamonium on 12/12/2007 1:58:13 AM , Rating: 2
Indicators within cells would require a device that could freely and easily go through cell membranes. Generally only very small molecules can do this (ie: smaller than nanotubes), and even then, the rate of diffusion is pretty slow. Cell surface antibodies make the most sense, and the body operates using similar mechanisms to begin with.


RE: Resistance be gone
By TSS on 12/12/2007 1:53:57 PM , Rating: 2
i wonder how the concept of "nano-waste" also comes into play with this.

I'm no expert, not even an amateur on this field so i might be wrong... but i don't think our body has any way of dealing with carbon nano-tubes. once we start putting those in our body's at high concentrations... well....

it'll be pretty ironic if in 30 years cancer is cured but the no.1 killer is CNT poisoning....


RE: Resistance be gone
By tmouse on 12/12/2007 2:27:03 PM , Rating: 2
You are correct; now I suppose you could try to incorporate a ligand that is actively transported by the cell however there you run into the specificity problem. These transporters are more generally expressed and almost never different between normal and abnormal cells. One possibility is a dual form device with a general internalized nanotube target arm and a more specific internal target ligand that would require the binding to its target to put it into a specific configuration for activation to produce the free radicals. I do not know if this is possible but please remember you heard it here ;)


RE: Resistance be gone
By tmouse on 12/12/2007 2:35:50 PM , Rating: 2
In regards to the nano waste my best guess is the targeting parts have a limited half life as all proteins do. After they degrade they will not be able to enter the cells and just be cleaned up and disposed of. This would have to be done any ways otherwise the destruction via the free radicals would also damage other cells who just happen to be near a circulating nanotube which would not be a good thing. Free radicals also can and do cause DNA damage ie: they can also cause cancer so its still a bit of a double edged sword but good work none the less.


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