Brains, LEDs and Super microscopes – 2014 Nobel Prize winners
This week saw the announcement of the 2014 Nobel Prize in the fields of Medicine or Physiology, Physics, and Chemistry. The annual prizes are awarded for outstanding discoveries within their respective fields. This year, the discovery of the brain’s internal GPS system, the invention of the blue LED and the development of fluorescence microscopy were recognised for their trailblazing scientific innovation.
Medicine or Physiology – Discovery of the cells making up the brain’s GPS system
This Nobel prize was split evenly between two parties. John O’Keefe of UCL received half the award and a share of the £690,000 prize for work he carried out in 1971. His ground-breaking work culminated in the discovery of ‘place cells’ in the brains of rats. O’Keefe started to record signals from individual nerve cells in rats as they moved within a room. From his investigation of the hippocampal region he noticed that specific nerve cells, later named place cells, fired as the rats reached certain locations within the room.
The other half of the prize was awarded to a married couple, May-Britt and Edvard Moser of the Norwegian University of Science and Technology. The couple met in the 1990s as postdocs working in O’Keefe’s lab, and are only the fifth Nobel couple since the prize’s inception in 1901. Their portion of the award recognises their 2005 discovery of ‘grid cells’ within the brains of rats.
This discovery provided an understanding of how the individual locations recorded by O’Keefe’s place cells are linked together. Aptly named ‘grid cells’, they form a uniform pattern when they fire, providing an internal coordinate system akin to the familiar latitude and longitude. It was resolved that the coupling of these location-sensitive grid and place cells forms the basis of our own human internal ‘GPS system’, which in turn supports our autobiographical memory.
Physics – Invention of the blue LED
Isamu Akasaki and Hiroshi Amano of Nagoya University in Japan, alongside Shuji Nakamura of UC Santa Barbara shared this year’s Prize for Physics. The award recognised their efforts leading to the invention of an efficient blue light-emitting diode.
Light-emitting diodes (LEDs) are made of semiconducting materials that convert electrical energy into light energy, with almost perfect efficiency. As a current is applied across a material, electrons flow and combine with their counterparts, known as holes, releasing a discrete burst of light in the process. The colour of this light depends on the specific properties of the material in use.
Green and red LEDs were created in the 1960s, yet the blue LED remained a long-standing challenge for scientists in both academia and industry until the 1990s. Despite a torrent of research, it was these three scientists who were the first successful; they perfected a method of growing large crystals of gallium nitride (a tripping point in previous research), allowing them to produce the distinctive blue light.
The development of the blue LED was a true game changer for the technology industry. The combination of blue with green and red LEDs produced white light, a feat that was impossible before the work of these three men. Today, blue LEDs are found in most people’s pockets worldwide, inside the screens and lights of everyday smartphones. White LED lamps have also been manufactured through the combination of these three colours and are widely used today due their superior energy efficiency.
Chemistry – The development of super-resolved fluorescence microscopy
In the late 1800s, it was assumed that the best resolution of an optical microscope was determined by the wavelength of light used. This year’s Chemistry prize was awarded to Americans Eric Betzig and William E. Moerner, and German scientist Stefan W. Hell for their work developing techniques that smashed through this microscopic barrier, bypassing the maximum resolution of traditional optical microscopes.
Fluorescence is essentially the emission of light from a substance that has previously absorbed light. The novel microscopy techniques developed by the aforementioned take advantage of the fact that individual cells can be stimulated to fluoresce, allowing the glowing area to be seen clearly. In 2000, Hell was able to image a single bacterium at unprecedented resolution by, in essence, turning an optical microscope into a very precise torch. He did this by using pulses of light to stimulate fluorescent molecules within a cell, then viewing the clear, glowing point in an optical microscope.
Betzig and Moerner independently developed a separate technique of viewing single molecules. Moerner established a method of stimulating fluorescence in individual molecules within a cell in 1997, before moving the focus to adjacent molecules. By superimposing the images in 2006, Betzig was able to create complete pictures of parts of cells.
Fluorescence microscopy is a technique that is today highly cherished within the fields of biology and biomedical science. It has allowed scientists to see what was thought the impossible, in real time. Amongst other chemical reactions, thanks to fluorescence microscopy we are now able to watch DNA being built, see molecules in action within living cells, and track proteins associated with Alzheimer’s and Huntington’s disease.
Main image: Dan Hansson/TT