Nanoknives To Be Used to Cut Cells

Roland Piquepaille writes "American researchers have built a carbon nanotube knife. According to the National Institute of Standards and Technology (NIST), this nanoknife will be used to cut and study cells. With this new tool, scientists and biologists will be able to make 3D images of cells and tissues for electron tomography, which requires samples less than 300 nanometers thick. And as cells are usually stored in wax for dissection, the researchers plan to test their nanoknives on a block of wax later this year. But read more for additional references and a picture of this nanoknife."

Comments

How hard is it to wrap a carbon nanotube?

[Josh Lindenmuth]

From the article:

It doesn't seem that this tool will be available before a while. The researchers have "found that the welds were the weakest point of the nanoknife, and they are now experimenting with alternative welding techniques."

Wouldn't it be better to wrap or tie the carbon nanotube to a specially shaped tungsten needles rather than trying to weld them? Given the small size, welding directly to the needles seems like it could never work ... better to rely on the strength of the nanotube than on the adhesive capacity of some other material.

If it's so thin

[TubeSteak]

Will getting "cut" by it make you bleed?
Will it even trigger your nerves?

Re:If it's so thin

[NanoProf]

That's an interesting question- the thinnest possible nanotube knife, a single single-walled nanotube, is about 1 nanometer wide. I could imagine that a living cell membrane would self-heal as a nanotube knife passes through it, since the cell membrane is a dynamic fluctuating entity. Bigger problems would be created with the knife hit a large, covalently bound molecule, or a macromolecular assembly held together by strong non-bonded interactions (muscle fiber, microtubule, bone, extracellular matrix of various kinds). I'd think that many of those things wouldn't self-heal very well, but it's not totally obvious to me that the damage pathway would be wide enough that slowly passing a nanotube knife through say, an arm would make it fall off, or prevent it from healing back together over time. If I had to bet, I'd say yes, it would either fall off or end up attached so tenuously that it dies and falls off later, but who knows... (one problem is that a single nanotube is most likely not strong enough to slice through an entire arm)

Re:Obligatory

[cyfer2000]

Actually they did. The art of cutting thin slice is called microtomy. Glass knife and diamond knife are used for microtomy. The advantage of glass knife is cost, the glass cost almost nothing. But glass knife doesn't last long, it gets blunt after 20 or 30 cuts. Also glass knife become blunt even you do nothing with it because glass is essentially fluid and the sharp edge has huge surface tension. Diamond knife lasts forever if you don't do anything wrong with it. But the diamond knife is pricey, a single knife can cost several thousand of dollars.

I have been doing microtoming for years. But I don't see how could this can be used to replace diamond knife. Basically we need to trim the sample to 0.1x0.25mm block and cut the block. This is small but still 100um. I at least need a knife of 150um wide to work on this. Nanotubes as long as 150um are not so well available at least for now. Then the knife is a 150um long 10nm thin wire, which I can not see with my eyes. How do I know the wire is stretched? And if it is stretched, during the cutting, the temperature and change from room temperature to -90 degree C. So how do I handle the thermal expansion? Also the problem troubled me mostly is how do I handle the section? When I am using a glass or diamond knife, the section and block fall to different sides of the knife, then I can use special tools to pick the section up. But when the wire cut through the sample, the section sticks back to the block. Also how much the wire knife cost and how long it can last? I can resharpen a 3mm diamond knife for $1500 after I made enough mistakes on it, which can be 5 or 10 years.

However, I really think this thing can be used as a wire saw to make MEMs.

Were none of the researchers ever boy scouts?

[lindseyp]

If the nanotube itself is the strongest part of the system why weaken it by welding it to the tungsten?

If they can manipulate objects at such a scale, They would surely get much better results by tying the nanotube to suitably shaped anchors.

Off the top of my head, a bowline would be a good start, I'm sure some slashdot sailor could suggest a loop knot or hitch more suitable for a slippery line.

easy solution

[EraserMouseMan]

All they really need to do is cut a nano-width-slot in each side of those tungsten prongs (creating a two-pronged fork on each prong). Then create a nano-axel by welding a small bead to each end of the nano-tube cutter (each bead being larger than the width between the fork prongs). Slide the nano-axel between the two tungsten forks. Pinch the ends of the forks together. Bingo! The nano-cheese-cutter can bend as much as it needs to and there are no fixed points to break.

Re:Not surprised...

[MSBob]

Yeah, with all the recent announcements it's pretty hard to disregard Kurzweil's predictions. I was very sceptical of his claims until I realized that his timeline appears to be dead on so far.