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

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)

I've already seen that

[macadamia_harold]

According to the National Institute of Standards and Technology (NIST), this nanoknife will be used to cut and study cells.

I saw my first nano knife when I brought my nano on the subway in New York. The guy took my wallet, too.

Re:How hard is it to wrap a carbon nanotube?

[imsabbel]

Friction on atomar level isnt what you are used to.

Trying to tie or wrap those nanotypes would be more than futile.

Size scales

[SiliconEntity]

It's easy to get sizes mixed up. Nanometers, microns, angstroms, they all sound about the same.

300 nanometers is a third of a micron. Cells vary greatly in size and shape but a ballpark figure for human cells is 20 microns. So we're not talking about something that is all that "sharp" compared to the size of the object it aims to cut.

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.

The basics

[Anonymous Coward]

The idea here is that the carbon nanotube may be able to replace the diamond or glass knives typically used for cutting biological specimens which have been embedded in a cured plastic resin. The knife and the sample to be cut are mounted on an ultramicrotome and then sectioned at 50-90nm increments.

TFA states that the carbon nanoknife has yet to be tested cutting anything, so it's unclear to me the extent to which it could be used to replace a diamond knife. Also, a diamond or glass knife edge can be millimeters long, whereas this nanotube thread looks much shorter.