Bioengineering of the Future: Optogenetics


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By Oliver Engel | Blogger | SQ Online (2013-2014)

Over two hundred years ago, an Italian scientist named Luigi Galvani attached wires to the legs of a dead frog and fired electrical impulses into the lifeless body, discovering that it moved as if it had come back to life.

Since then, scientists have used this concept to manipulate the brain to treat diseases like Parkinson’s and dystonia.  Because information is transferred through electrical impulses, influencing those impulses will naturally allow us to influence the overall patterns of the brain. But this process, sometimes known as electrical brain stimulation, is a bit messy. There’s only so much room for wiring, and even if we could observe the actions of every single neuron, we wouldn’t be able to make much sense of it.

The process of electrical brain stimulation, used here to treat Parkinson’s, is extremely invasive and complex.

Here’s where bioengineering comes in: Gero Miesenböeck, a professor at the University of Oxford, is re-engineering the brain in such a way that a complex set of technological devices are no longer needed. His approach is called “optogenetics,” where light is used to activate neurons that have been genetically modified for light sensitivity (fun fact: Francis Crick, the co-discoverer of the structure of DNA, actually outlined this idea during a 1999 series of lectures here at UCSD!). Check out Miesenböeck’s TED talk below for more information on the field of optogenetics.

The process of optogenetic experiments is extremely complex, but its concept is actually fairly simple. Using gene therapy techniques, photoreceptor genes from organisms like algae are implanted into specific neurons in the brain, and are activated by lasers installed into the skull, allowing those certain neurons, and those neurons alone, to be activated at will. If you want an in-depth explanation of how and why this process works, check out this TED talk with MIT neuroscientist Ed Boyden.

Two mice with light-emitting “helmets” used in optogenetic experiments. Source: Discovery Magazine

Such a cross between engineering, technology, and biological systems has huge and potentially revolutionary prospects for healthcare and other aspects of science. Miesenböeck is primarily interested in using this advancement to control animals: in one experiment, his colleagues implanted photoreceptor cells in a Drosophila, in the neurons responsible for its instinctual ability to quickly maneuver away from danger. With just a flash of light, the flies jumped and attempted to fly away. But even more interesting: the scientists then removed the heads of the flies and repeated the experiment—again, the flies tried to escape. This confirms the effectiveness of such a strategy, because the organisms do not even have to be conscious (or in one piece) for it to take effect.

Brief visualization of the process of optogenetic experiments. Source: Brown University

Re-engineering the brain has more to offer than controlling the behavior of organisms, however. In the above TED talk, Ed Boyden lists just some of the clinical applications of optogenetics. He describes an experiment in which scientists implant photoreceptor cells into the retina of mice affected by different types of blindness. The result is astonishing, and the once-blind mice are able to successfully navigate a puzzle in the same amount of time as regular mice. Boyden hopes to expand these experiments to humans as the the procedure is refined over time.

Optogenetics provides a different approach to the subject of medical treatment. We have been limited in what we can achieve because we have mainly focused on two methodologies: drug-based therapeutics, which are often symptom-oriented instead of holistic, and external manipulation, like physically attaching electrical conductors to the brain. But we are now on the cusp of a new era in which we are able to conform biological systems to fit our technology, not the other way around. For this reason, bioengineering is more important than ever, and will probably be one of the most prominent scientific fields of the future!

Sources/Additional Reading

Ed Boyden’s TED talk on the implications of optogenetics

Gero Miesenböeck’s TED talk on re-engineering the brain

MIT video explaining optogenetics

Recent New York Times article on optogenetics

Scientific American article explaining applications of optogenetic discoveries

 



About

Oliver is a first-year human biology major from Muir College, who loves everything from science and literature to music and art.