Getting Closer To DNA Computing

jwambach writes: "This brief article over at Yahoo! describes how scientists are attempting to create molecular electronic circuits using DNA. They say that they could potentially create circuits 10,000 times smaller than with current technology." The article says that "[r]esearchers have already created molecular wires, logic gates (a building block of computers) and switches, which could be hooked up to make a working computer a fraction of the size of ones based on silicon chips." The coolest part is that assembling the tiny components could be done with DNA-tagged components, shaken (or stirred) in a test tube.

Comments

Nanotech is still far away

[GMOL]

The article suggests that we have all the molecular tools and that it is a straightforward matter of hooking them together to make molecular scale computers/robots....this is misleading. There have been a number of published papers that describe molecular logic gates (based on 'inputs' of ions, or particular DNA strands) and the 'output' is often flouresence...which doens't allow you to hook these components up into large arrays. I have tones of ref's if anyone cares to look them up. Even things like Adleman's approach, while actually quite brilliant in design, fail to provide either faster more efficient computers or application to control (bio) chemical systems. Winfree's stuff with Seaman's DNA cubes is again quite interesting, but it's difficult to see where it will go or what insight it will provide. Anyone remember bacteria rhodopsin based memories? I think work continues on them, but no one sees practical application. The stuff coming from UCLA and HP (rotaxanes) is actually quite interesting; and given the population of things that has to do with molecular computing; it probably has the greatest chance of actualy realization.

Most real nanotech you see today is just some real nice bio/organic/supramolecular chemistry that has been moving along since the inception of chemistry (a-hemolysin stuff, self replicating peptides, nanotubes etc.). Not to say that it isn't wonderful work or un-useful...but it is just renamed chemistry.

The other thing I have a problem with people like drexler is that suppose one does actually succeed in producing one of the molecular machines he describes through synthesis or AFM techniques...we don't have the technology to characterize such beasts. Ask an enzymoligst how many molecules of enzyme he needs and the things he neeeds to know before he can say what an enzyme is doing (or what it looks like). Enzymes are in many ways much simpler than the kinds of things Drexler proposes. In other words even if you could build a nano-bot; I don't know how you could know it was actually there or convince other scientists given the trouble we have with the molecules that nature has given us.

What is frusturating out the whole molecular computing field is that when you actually try to sit down and do it, it seems impossible to try to figure out a way to do computation on a molecular level....yet natural things like remarkably organized biological cell and the human brain show us that there is a way, but is it the only one?

From A While Back

[Metrol]

I knew I had read about a very similar set of experiments going on with DNA in Wired. I didn't realize how long ago it was. Anyhow, I did me a search over there on the mag and found the article in their archives called Gene Genie -Aug1995. This is a rather old article, and I honestly have no idea how far this guy got with his research.

To quickly summarize, this Adleman fella actually got DNA to do some simple calculations. What the biggest stumbling block at that time (and most likely still) was getting an interface between the user and the DNA setup. Sounds like that's what these folks in England are up to now.

I feel I should clarify one point that seems to be getting mixed up here on this thread. The promise of DNA based computers isn't specifically to replace CPU's that we know today. In fact, DNA is far slower at running the repititive kinds of tasks that silicon deals with. The exciting stuff is in it's ability to do massive parallel processing on a small scale.

For example, if you had a race between silicon and DNA to count to 1e24 the silicon would most likely be a clear winner. On the other hand, DNA based processors usher in the ability to solve problems that silicon based machines simply can't do, like calculate a perfect game of chess.

Most likely, what we'll eventually see out of all this is a new hybrid computer utilizing both silicon and DNA based on their individual strengths. The prospects for this are both very cool, and very scary. We're talking about a machine that literally removes every advantage the human brain presently enjoys over silicon CPU's in the way of problem solving. Imagine HAL, only one hell of a lot smarter.