Metal/Bio Linking Advance

[groovychk]

Implications: Cybernetics/Bionics that truly interface with the body (for one)
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http://www.eurekalert.org/pub_releases/2006-05/uotm-nuf050806.php

Nanotubes used for first time to send signals to nerve cells

GALVESTON, Texas --Texas scientists have added one more trick to theamazing repertoire of carbon nanotubes -- the ability to carryelectrical signals to nerve cells.

Nanotubes, tiny hollow carbon filaments about one ten-thousandththe diameter of a human hair, are already famed as one of the mostversatile materials ever discovered. A hundred times as strong as steeland one-sixth as dense, able to conduct electricity better than copperor to substitute for silicon in semiconductor chips, carbon nanotubeshave been proposed as the basis for everything from elevator cablesthat could lift payloads into Earth orbit to computers smaller thanhuman cells.

Thin films of carbon nanotubes deposited on transparentplastic can also serve as a surface on which cells can grow. And asresearchers at the University of Texas Medical Branch at Galveston(UTMB) and Rice University suggest in a paper published in the Mayissue of the Journal of Nanoscience and Nanotechnology, these nanotubefilms could potentially serve as an electrical interface between livingtissue and prosthetic devices or biomedical instruments.

"As far as I know, we're the first group to show that you canhave some kind of electrical communication between these two things, bystimulating cells through our transparent conductive layer," said ToddPappas, director of sensory and molecular neuroengineering at UTMB'sCenter for Biomedical Engineering and one of the study's seniorauthors. Pappas and UTMB research associate Anton Liopo collaborated onthe work with James Tour, director of the Carbon NanotechnologyLaboratory at Rice's Richard E. Smalley Institute for Nanoscale Scienceand Technology, Rice postdoctoral fellow Michael Stewart and Ricegraduate student Jared Hudson.

The group employed two different types of cells in theirexperiments, neuroblastoma cells commonly used in test-tube experimentsand neurons cultured from experimental rats. Both cell types wereplaced on ten-layer-thick "mats" of single-walled carbon nanotubes(SWNTs) deposited on transparent plastic. This enabled the researchersto use a microscope to position a tiny electrode next to individualcells and record their responses to electrical pulses transmittedthrough the SWNTs.

In addition to their electrical stimulation experiments, thescientists also studied how different kinds of SWNTs affected thegrowth and development of neuroblastoma cells. They compared cellsplaced on mats made of "functionalized" SWNTs, carbon nanotubes withadditional molecules attached to their surfaces that may be used toguide cell growth or customize nanotube electrical properties, to cellscultured on unmodified "native" carbon nanotubes and conventionaltissue culture plastic.

"Native carbon nanotubes support neuron attachment and growthwell -- as we expected, better than the two types of functionalizednanotubes we tested," Pappas said. "Next we want to find a way tofunctionalize the nanotubes to make neuron attachment and communicationbetter and make these surfaces more biocompatible."

Another avenue Pappas wants to explore is finding out whethernanotubes are sensitive enough to record ongoing electrical activity incells. "Where we want to get to is a device that can both sense anddeliver stimuli to cells for things like prosthetic control," Pappassaid. "I think it's definitely doable, and we're pursuing that with JimTour and his group. It's great to be able to work with a guy who's onthe cutting edge of nanoelectronics technology -- he seems to developsomething new every week, and it's really become a great interaction."

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