Nanotubes boost neuron growth

Researchers from the University of California at Riverside have coaxed neurons from a rat's brain to grow on a mat of multiwalled carbon nanotubes.

The method is a step toward neuron-electronic interfaces that would allow for direct biological control of computers and prosthetic devices.

Carbon nanotubes are rolled-up sheets of carbon atoms that are a natural ingredient of soot, can be smaller than one nanometer in diameter, and have useful electrical properties. Multiwalled carbon nanotubes consist of a group of nested tubes.

The researchers produced nanotubes of positive, neutral and negative surface charge by attaching different molecules to the ends of the tubes. They coaxed neurons taken from a rat hippocampus to grow on the carbon nanotubes and measured the growth and branching of the neurons' arms, or neurites.

They found that the surface charge of nanotubes can be used to control the outgrowth of neurons. Positively-charged nanotubes turned out to be better substrates than neutral or negatively-charged nanotubes. The neurons grew for a week, which shows that long-term integration of nanotubes and nerve cells is possible, according to the researchers.

The researchers are working on linking neurons to silicon devices using carbon nanotubes as intermediaries.

Practical neuron-silicon interfaces for computers and prosthetics are 10 to 20 years away, according to the researchers. The work appeared in the March 10, 2004 issue of Nano Letters.