Growing Wires In Water

moooooooo writes: "Australia's ABC is reporting that U.S. researchers have discovered a new way to grow microscopic electrical wires in water, and soon hope to be plugging into living cells. Kevin D. Hermanson and colleagues from the University of Delaware created self-assembling, self- repairing conductive wires -- a micrometre in diameter and 5 mm in length -- by suspending gold particles in water between two electrodes."

is "fuzzyness" a problem

[tony_gardner]

Looking at the pictures, I notice that a lot of the wires look very fuzzy. I'd think that these would bleed signal like crazy and be an impedence nightmare for non-DC signals. Still pretty impressive though.

An interesting point relating the article to the press release here:

http://www.udel.edu/PR/UDaily/01-02/microwire110 20 1.html

In the article, it's all about bio-interfacing and what an advance this is. The press release says:

"One very interesting, albeit yet remote, possibility is to use these wires for electronic-biology interfacing," Velev said.

Not quite the same thing.

In addition, in the article, it broadly quotes a Professor Gerard Milburn. I find this quite interesting, in an article on biology and chemistry. He was my old Head of Department. He's a theoretical quantum physicist working in quantum measurement and quantum computing. Not my expert of choice in this field.

There's a third image not on the page.

[t]

http://www.abc.net.au/science/news/img/nanob.jpg [abc.net.au]
It musta got cut.

t.

Links to actual science info

[oldbox]

Judge for yourself if the ABC news and /. submission are kind of overblown. Interesting for connections across different scales tho.

Dielectrophoretic Assembly of Electrically Functional Microwires from Nanoparticle Suspensions
Kevin D. Hermanson, Simon O. Lumsdon, Jacob P. Williams, Eric W. Kaler, and Orlin D. Velev

Abstract:
A new class of microwires can be assembled by dielectrophoresis from suspensions of metallic nanoparticles. The wires are formed in the gaps between planar electrodes and can grow faster than 50 micrometers per second to lengths exceeding 5 millimeters. They have good ohmic conductance and automatically form electrical connections to conductive islands or particles. The thickness and the fractal dimension of the wires can be controlled, and composite wires with a metallic core surrounded by a latex shell can be assembled. The simple assembly process and their high surface-to-volume ratio make these structures promising for wet electronic and bioelectronic circuits.

Science Nov 2 2001: 1082-1086.

[Full Text] [sciencemag.org] (only if you have a science account)

[Supplemental Data] [sciencemag.org] - including QT movies!

Diffusion limited aggregation?

[HorsePunchKid]

It'd be nice to see some more background; in particular what inspired them to try this. It sounds like just basic DLA [polyu.edu.hk]. You use the EM field between the carbon "islands", then the conductive particles in suspended in the liquid move along the field lines in a somewhat Brownian manner (i.e. random, but statstically biased because of the field). Then just set it up so the particles stick to eachother. I wrote (and no doubt many others have, too) a program to simulate this. You can set up groups of attractors that follow different physical laws (e.g. inverse-square, linear, exponential), then set up particle sources (e.g. ambient sources, point sources, linear, circular, etc.). Hit "start", and you see the particles very slowly (i.e. hundreds of thousands of particles) build up into these dendritic structures. It's cool to see somebody actually doing physical work applying the theory, though.

Magneto becomes reality?

[Mr. Eradicator]

So how would this apply to a human body? Could this be used to run strands of conductors through a human capillary system? Could a person then have interesting EM "things" happen to them ... or could they in turn use body chemistry to induce electric/magnetic fields around them? Freaky concepts...

electromagnets

[drwho]

You could build a matrix of inductors, hook them up to micro-sized rectifiers, and get DC from random EM fields. Fun!