Femtosecond Lasers for Nanosurgery

Roland Piquepaille writes "In "Lasers operate inside single cells," Nature writes that nanosurgery can be achieved by vaporizing some components of living cells without killing the cells themselves. "With pulses of intense laser light a millionth of a billionth of a second long, US researchers are vaporizing tiny structures inside living cells without killing them. The technique could help probe how cells work, and perform super-precise surgery." This was developed by Eric Mazur of Harvard University and his colleagues. This summary contains more details and references about the process and these microexplosions. Please note that it's a very different technique from the one described six months ago in a previous Slashdot reference, Surgery with Femtosecond Lasers."

Comments

Evolution

[LordoftheFrings]

It has been said that evolution of cells must have been impossible, because each part of the cell is necessary for the cell to live, and thus they must have all evolved at the same time, which is highly unlikely. Perhaps this is a way to test that theory?

Re:Evolution

[kfg]

How can a car possibly exist? It needs all of its parts or it is not a car. All of it's parts must fit and work with each other precisely so they could not have been designed seperately.

Do you see the fallaciousness of the argument?

Wheels, engines, suspension systems, steering mechinisms, all "evovled" prior to cars and for functions having nothing to do with cars.

It not necessary for a cell to spring into being as a whole entity. It is only necessary that it's basic componants can come into being and exist without the cell for some other purpose.

As it happens any close inspection of a cell quickly reveals that it isn't a single entity but a unit made up of preexisting parts, just as is a car.

Evolution does not build anew each orginism. It is and additive process. This is why you can make a good study of human anatomy by disecting a chicken. Things grow like an onion, accreting new layers of development atop the old.

This idea is absolutely critical. The current state of evolution is not the paragon of some process that replaces what went before. We can examine nearly the full range of the evolutionary process because all the older forms still exist.

Evolution does not erase its tracks. You can peel the onion.

KFG

Cancer?

[BWJones]

Hmmmmm. These techniques, combined with multispectral analysis of tissues in real time could be just the ticket for surgical resection of certain cancers(meningiomas etc....). The multispectral analysis could be combined with a robotic laser that could automatically lase the "transformed" tissues, thus selectively killing cancerous cells. Cool.

Re:Cancer?

[BWJones]

However, the real problem lies in the focus of the light

No, tuneability of lasers to specific tissues and degrees of intensity are well worked out.

and how do we distinguish between well-behaving cells and carcinoma?

That is the point of the multispectral (potentially) analysis. The idea is that you in real time identify characteristics in normal versus transformed cells.

On a cell-to-cell scale?

That was the point of this article.

It would then costs millions to have a surgery getting one simple surgery done with the lasers and it would last ages.

No, it could cost significantly less to have the laser surgery, could provide a better outcome, reduce the time in surgery and under anesthesia and reduce infection rates.

If you think any kind of staining/identifying can work with computers that automate the thing then you better think who is to blame if such things happened.

Hrmmmm. You had better look at the remote sensing community. These folks going back to the 1970's in the CIA and NRO have been using computers to automate identification of multispectral targets for almost 4 decades.

Couldn't this be used for hi-res printing?

[192939495969798999]

If you can affect something inside a single cell accurately, couldn't this same technology be used to alter ink colors for super high-resolution laser printing? Like 10,000 DPI non-interpreted?

Coincidence? I think not.

[MisterSquid]

This was developed by Eric Mazur of Harvard University and his colleagues.

The MASER was the predecessor of the LASER. Though most don't know this, LASER is an acronym standing for "light amplification by stimulated emission of radiation." The difference is that MASERs amplify Microwaves instead of light.

Isn't it convenient that the lead scientist on this is named just happened to be named "Mazur?" . . . Waitaminut, where'd that black helicopter come from?

(You can get a little info about MASERs and LASERs here)

Re:nature writes?

[JDevers]

Lay off the ketamine for a second and re-word that...

For the most part, magazines such as S.A., New Scientist, etc "paraphrase" the work presented in journals such as Nature or Science. While it may take a while for something to be peer-review and printed in a journal, it isn't really considered all that trustworthy until it is.

There are occasions where huge papers "debut" in a peer reviewed journal at the same time as a corresponding article in one of the mainstream science mags, but it was definitely the journal article which came "first."

Of course, that may have been exactly what you said...I just couldn't understand what you were saying.

On a related note.

[I'm a racist.]

I work with femto-second lasers. I have used them in living cells for a variety of applications. Two of which involve destroying structures inside of living cells. Of course, these structures are placed into the cells by us (injection, knock-in, electroporation, etc). It's not an extremely new technique, it's just being used in a slightly new way. Some of the similar techniques are known as uncaging, FRAP, and more.

Personally, I rarely find anything that groundbreakingly new in Nature. Well, that's not exactly true. There is plenty of new data, and new applications and/or refinements of old techniques. There generally aren't wholly original techniques or completely new instruments discussed in that journal. My personal preference for that sort of thing are some physics journals.

One other thing, that may be of interest to /., semiconductor nanocrystals are starting to pop up in similar research. They are quite useful, if still hard to work with (they don't behave like most biological molecules). I got interested in quantum dots about a year ago, and have done a bit of work with them, but would like to do some more (when I find the time).

Re:genetics

[Mercaptan]

It's a nice thought, but even these lasers aren't precise enough to alter genes on living chromosomes.

Mitochondria are about 5 micrometers across and your various cytoskeletal filaments and tubules range between 3 - 25 nanometers in diameter.

Human chromosomes, on the other hand, are essentially 2 meters of DNA packed into a 5 micrometer-wide nucleus. Now that's 6 billion base pairs (A/T's and G/C's), which are wrapped up pretty tight.

If you stretched out the DNA to full length, that's 3.4 x 10e-10 meters per base pair. Taking a randomish gene that's 10,000 base pairs long, that would work out to 3.4 micrometers of DNA, which this laser could work on. But if you think refolding maps is hard, imagine trying to repack 2 meters of DNA back into a 5 micrometer nucleus.

During metaphase, when the cell has all its chromosomes lined up and ready for splitting, the average size of a chromosome is 2 micrometers from end to end. Basically, your 10k base pair gene is now just 1.7 nanometers long. All of this winding and compacting means that it's blessedly hard to hit a single gene and only that gene within the DNA contained in a living cell with a tool this blunt.