Wednesday, 4 April 2012

'Living Lasers'


Superman's laser vision
‘Living Lasers’
By Sabrina Oishi

Ever wished that you could shoot laser beams out of your eyes like Superman? 

Well, scientists for the first time have successfully genetically engineered a living cell to emit laser lights, dubbed the ‘living lasers’, at the Wellman Centre for Photomedicine in Massachusetts. Originally, lasers were made by non-biological materials but according to Nature Photonics., Professors Malte Gather and Seok Hyun Yun reported that they were able to use “biological materials to build a laser and generate light from something that is living.”

How does it work?
Scientists used the three basic components of typical lasers: a ‘gain medium’ which was an external material that amplified light, energy source that excited atoms to emit light, and mirrors that acted as an ‘optical cavity’ to direct the light waves into a beam. They also used a protein called green fluorescent protein (GFP) found in jellyfish as the key to their investigation. The scientists genetically engineered human embryonic kidney cells by inserting the GFP gene, thus creating the biological ‘gain medium’.  A single GFP modified cell was then placed in between two highly reflective mirrors that were 20 millionths of a metre apart, thus forming an ‘optical-cavity’. This cavity was then exposed to blue light as the energy source. Usually, when GFP was exposed to blue light, the cell would just glow green. However, the mirrors used in the ‘optical cavity’ excited the photons at a more increasing rate than the blue light it was energised by, thus, allowing the GFP molecules to emit green laser light beams.


According to the journal, the single cell survived without damage after emitting “a few hundred pulses over several minutes”. Researchers Yun and Gather suggested that due to the laser light emitting “unique emission spectrums related to both the structure of the cell and the proteins inside it,” further analysis can be done on the cell’s functions.

Future applications?
Biological lasers can possibly lead to practical applications in the future. Medical applications in photodynamic therapies can be used to treat diseases, for example, activation of a drug by light once it is inside the patient’s body to attack virus cells. Furthermore, biocompatible lasers can be inserted into human bodies, thus penetrating relevant tissues deeper and gathering clearer images.

Although the first ‘living lasers’ are not strong enough to disintegrate metal like Superman can, it’s still an incredible breakthrough for genetic engineering technology.



References:
1.        Corbyn, Z. (2011), Human cell becomes living laser, Nature Publishing Group, viewed 17 March 2012, http://www.nature.com/news/2011/110612/full/news.2011.365.html.
2.        Gather, M.C. and Yun, S.H. (2011), 'Single-cell biological lasers', Nature Photonics, vol. 5, pp. 406-410 viewed 17 March 2012, DOI:10.1038/nphoton.2011.99.
3.        Hanna, E. (2011), First laser made of living cells has arrived, Discovery News, viewed 17 March 2012, http://news.discovery.com/tech/the-first-laser-made-of-living-cells-has-arrived.html.
4.        PhysOrg.com. (2011), Signle green fluorescent protein-expressing cell is basis of living laser device, Phys.Org.com, viewed 17 March 2012,
http://www.physorg.com/news/2011-06-green-fluorescent-protein-expressing-cell-basis.html.
5.       Ross, V. (2011), Researchers build a living laser, Discover Magazine, viewed 17 March 2012, http://blogs.discovermagazine.com/80beats/2011/06/13/researchers-build-a-living-laser/

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