Nanotech Trojan Horse That Kills Cancer

An anonymous reader writes "University of Michigan scientists have created the nanotechnology equivalent of a Trojan horse to smuggle a powerful chemotherapeutic drug inside tumor cells - increasing the drug's cancer-killing activity and reducing its toxic side effects." From the article: "The drug delivery vehicle used by U-M scientists is a manmade polymer molecule called a dendrimer. Less than five nanometers in diameter, these dendrimers are small enough to slip through tiny openings in cell membranes. One nanometer equals one-billionth of a meter, which means it would take 100,000 nanometers lined up side-by-side to equal the diameter of a human hair."

Comments

How it works

[Kainaw]

In case you are like me and you just want to know how they targetted the cancer cells, this is a very brief rundown:

All cells require folate to survive. Cancer cells suck up folate like it's crack. They put the poison in the folate. All cells absorb some of the poisoned folate. Cancer cells absorb most of it.

Pretty nice idea, but it made me wonder about the push to get expectent mothers to take excessive amounts of folic acid (folate). Does that make them more prone to cancer by giving the cancer cells extra food?

Medical nanotech

[Jerf]

Nice to see this start to happen.

Based on what I understand of nano-tech and the human body, I think we're going to see a lot more of this, and this will be the first medical nanotech revolution: Creating drugs that are targetted only at the things they are supposed to affect.

Imagine wrapping, say, kidney drugs in a nanotech container that only opens in the kindeys, and is otherwise harmless. Or imagine an anti-inflammatory that only targets inflamed areas.

This will cut down a lot on undesirable side-effects caused by flooding the entire body with something to affect .1% of it, and also enable us to up the dose as relevant only to the affected parts.

This obviously doesn't apply to everything, but this is the first advance I expect to actually get used. We're a long way from lil' machines that can safely clean out plaque from our arteries (though we recently saw some advances towards doing it unsafely this last week), but this is quite doable, I think.

Okay, so my questions are:

[Sialagogue]

From the article:

"The drug delivery vehicle used by U-M scientists is a manmade polymer molecule called a dendrimer."

Is this a biodegradable polymer?

Dendrimers have a tree-like structure with many branches where scientists can attach a variety of molecules, including drugs.

How hard is it to attach molecules to these tree-like structures? If these polymer dendrimer are exposed to various other molecules will some bond naturally, or do they have to be tailored to a specific molecule?

...scientists injected dendrimers with fluorescent tags into the bloodstream of laboratory mice to determine where they would be retained in the body. The results showed that the kidneys quickly filtered free nanoparticles from blood and eliminated them in urine.

Does that mean that in potential future patients, any free/unabsorbed nanoparticles will be excreted into the public sewage systems, and being (I assume) unfilterable, thereby enter the earths water cycle?

So when you put those together, will these nanoparticles be able to float freely in our oceans and rivers, their dendrimers bonding with molecules found in nature, and then if conditions are right potentially take those molecules inside our cell walls?

I know - the actual number of these things for cancer patients will be really small, but workable techniques tend to get expanded, and if they don't break down they'll just pile up over time. I'm not qualified to do anything but ask these questions, I'm just wondering whether there's any reasonable risk that once these hit the outside world they could turn around and be just as effective at delivering cancer-causing agents they pick up randomly from the environment.