What do trees, rivers, clouds and neurons have in common? They're all examples of fractals, or irregularly-shaped objects in which any one component is the same shape as the whole – a tributary of a river, for instance, looks like a miniature river itself. Electronic chips are not fractals, yet some researchers are trying to restore sight to the blind by attaching such chips to the eye's neurons. Given that neurons are fractals, wouldn't it work better to hook them up to other fractal structures? University of Oregon researcher Richard Taylor thinks so, which is why he's developing metal "nanoflowers."
Taylor notes that although digital cameras are getting closer to attaining the 127-megapixel resolution of the human eye, only a small percentage of that data could be relayed from implantable chip devices (such as photodiodes inserted behind the eye) to the brain. This is because existing chips simply can't connect with enough of the neurons – it's like trying to put 10 pegs into 1,000 holes.
His nanoflowers would be grown on chips, from metal nanoparticles. They would self-assemble, through a process of diffusion limited aggregation, into fractal structures that resembled neurons. Those fractal-structure-bearing chips would then be implanted into the eyes of blind patients, where they would provide an interface between light gathered by the retina and neurons serving the optic nerve. Because the chips would be able to connect with almost every neuron, their efficiency would be close to 100 percent.
University of Oregon doctoral student Rick Montgomery will shortly be starting a one-year collaboration with Simon Brown at New Zealand's University of Canterbury, in which they will be experimenting with growing the nanoflowers from different types of metals. One of the challenges will lie in finding a metal that doesn't cause a toxic reaction when implanted, but the possibilities are still exciting.
"We're right at the start of this amazing voyage," said Taylor. "The ultimate thrill for me will be to go to a blind person and say, we're developing a chip that one day will help you see again."
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