Cover Story: Neural Regeneration

One of the things I admire about science fantasy[1] (what I like to call Star Wars/Star Trek and anything else in which you can replace any technical terminology with the word ‘magic’ and achieve the same plot impact) is its complete and utter disregard for how things actually work. Despite a significant amount of scientific training, I can usually suspend my disbelief for this sort of thing very easily, and take a simple joy in the finished idea, without wondering how or why something works, or whether or not it’s even possible.

Occasionally, though, my professional instincts get in the way, and I find myself speculating over the fine details of how one might achieve some of the technological splendors and terrors that populate our cinemas, televisions, and books. How do you build an engine that can propel something eighteen times the size of an aircraft carrier at faster-than-light speeds? How did the doctor manage to regrow that guy’s arm? And just how do you go about building cyborgs?

For the latter two examples, it turns out that I may be being a little harsh in judging them as fantasy rather than fiction. If science fiction is grounded in current knowledge, growth of new nerves and tissue and electronic/bionic interfaces are no longer as far-fetched as they once were. A current challenge in regenerative medicine is to develop materials and procedures that can be used to support re-growth of damaged nerves or effective methods of interfacing nerves and neurons with electronic circuitry. These procedures could facilitate advances in treatment of damage to the nervous system, reconnection of severed nerves (for example in the spinal cord), and greatly enhance control and functionality of prostheses by being able to incorporate them directly into the body’s command and control systems.

Working towards this, Gordon Wallace and his team at the Intelligent Polymer Research Institute of the University of Wollongong have developed a new hybrid platform that can promote directed growth of neural tissue. This is one of the tricky aspects of nerve regeneration – controlling where the tissue will grow – but Wallace and his team have overcome this difficulty by incorporating unidirectional fibers of biodegradable polymer into the substrate platform, providing tracks for the nerves to grow along that will eventually degrade away, providing more space for the nerves to grow. The rest of the substrate platform is composed of a conducting polymer, which allows electrical stimulation of the growing tissue, thus promoting more effective growth and cell migration. Extending the concept to multidirectional fibers and structures, one can then imagine that such a strategy could be used to connect neural tissue to electronic circuits in specific locations, resulting in successful interfacing of nerves with biomedical monitoring devices or prostheses.

The cover picture for this work picks out all these critical points. The cutaway cross-sections of the nerve scaffold show the potential for the hybrid platform to be manipulated into 3D structures, and the background fluorescence microscopy image shows cell migration preferentially on the blue fiber stripes. The inset in the mouth of the scaffold conduit shows axon growth along real fibers, directionally controlled.

An awesome piece of research that means maybe Dr. McCoy’s Sickbay isn’t quite as much of a fantasy as it used to be.

DOI: 10.1002/adma.200901165

Lisa Wylie, Managing Editor Advanced Materials
www.materialisam.wordpress.com

[1] As opposed to science fiction, of which Robert Heinlein said: “a handy short definition of almost all science fiction might read: realistic speculation about possible future events, based solidly on adequate knowledge of the real world, past and present, and on a thorough understanding of the nature and significance of the scientific method." (Robert A. Heinlein, Cyril Kornbluth, Alfred Bester, and Robert Bloch, “Science Fiction: Its Nature, Faults and Virtues” The Science Fiction Novel: Imagination and Social Criticism 1959, University of Chicago, Advent Publishers.)

G. G. Wallace et al., Adv. Mater. 2009, 21, 4393 ; DOI: 10.1002/adma.200901165

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