Gold nanoparticles that make leaves glow in the dark

October 25, 2010 by Lin Edwards, report
Gold nanoparticles that make leaves glow in the dark
Image credit: Nanoscale, DOI:10.1039/C0NR00330A . For more details, please see the original publication.

( -- Researchers in Taiwan think they may eventually be able to replace street lamps with trees laced with gold nanoparticles that turn their leaves into bio-light-emitting diodes.

Light-emitting diodes (LEDs) are much more energy efficient than traditional light globes, but researchers in Taiwan by Yen Hsun Su and colleagues at Academia Sinica in Taipei and the National Cheng Kung University in Tainan wanted to find a way of making LEDs that were even more efficient than those currently available. They succeeded by synthesizing and implanting them into leaves of the Bacopa caroliniana plant to induce bio-luminescence in them.

Bacopa caroliniana is a perennial aquatic or semi-aquatic creeping herb commonly used as an aquarium plant. The color of the leaves varies in proportion to the amount of light, turning bronze to almost red when exposed to high light levels.

The green pigment in leaves, chlorophyll, is bioluminescent when exposed to high wavelength (400 nanometers (nm)) ultra violet , but the wavelength is much shorter for the of gold nanoparticles, and they emit light at 400 nm. The light is localized at a nanoscale and the nanoparticles made by the Taiwan team suppresses emission blinking, which is a problem already known in gold nanoparticles. Using their sea-urchin-shaped nanoparticles (dubbed nano-sea-urchins or NSUs), Su was able to excite chlorophyll in the leaves to emit red light.

Su said the bio-LEDs (light emitting diodes) might eventually be used to make trees lining roads luminescent at night, and since the light causes the chloroplast to conduct no energy source is needed and the plant will absorb CO2 for the process, which does not normally occur at night.

Su and his colleagues are looking at applying the same technique to other plant molecules and on trying to improve the efficiency of the process. Their work was reported in the journal .

Explore further: Scientists coax gold particles to emit light strong enough to view single nanoparticles

More information: Influence of surface plasmon resonance on the emission intermittency of photoluminescence from gold nano-sea-urchins, Nanoscale, 2010, Advance Article, DOI:10.1039/C0NR00330A

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not rated yet Oct 25, 2010
High Wavelength? This is confusing. One would usually term: Long / Short Wavelength Or High / Low frequency.
5 / 5 (2) Oct 25, 2010
Glowing trees... I want to live in a world that awesome. Hurry up and get it done!
5 / 5 (1) Oct 25, 2010
Screw las vegas, rainforest here we come! (with a truckload of gold)
4 / 5 (1) Oct 25, 2010
Talk about wide spread light pollution when that weed starts to spread...
4 / 5 (1) Oct 25, 2010
Danger Will Robinson Danger... Until a 30yr long term study is done in a domed forest to prevent spread and study the effects on trees health and reproduction I think this is a waste of gold. Trees probably need rest from absorbing energy and being 'on' just like everything else on the planet. And lets not forget that trees respirate or consume O to produce a usable sugar. What does this do the the life cycle of the plant -- and this bioluminesnce seems to be brought about by a catalyst so there is no growing or breeding these trees.
4 / 5 (1) Oct 25, 2010
So every fall all the leaves fall off and you have to invest in a bunch of gold again?
1 / 5 (1) Oct 25, 2010
.. asymmetry ...
not rated yet Oct 25, 2010
the wavelength is much shorter for the photoluminescence of gold nanoparticles, and they emit light at 400 nm.
WTF? Where is the "much shorter" wavelength light coming from, to trigger gold nanoparticle photoluminescence?? They're talking about extreme UV, I suppose? And this isn't going to damage the living plant cells? LMAO
since the light causes the chloroplast to conduct photosynthesis no energy source is needed
WTF?!?!??? How is no energy source needed, when the tree is either being bombarded with extreme UV (causing all passers-by to get sunburns, and the tree to wither and die), or the tree is otherwise consuming its own sugars to emit its own bioluminescence? Or does energy conservation not apply in Taiwan??

ROFLMAO @ this article...
not rated yet Oct 25, 2010
So every fall all the leaves fall off and you have to invest in a bunch of gold again?

I was thinking along similar lines though if the leaves were the light emitters, there goes your street lights soon as Fall settled in. As for the gold, hopefully the treatment lasts for a considerable amount of time and the bio luminescence re-emerges with new seasonal leaf growth. I certainty wouldn't retire those conventional street lights any time soon though.
not rated yet Oct 25, 2010
Pandora anyone? As long as the tree spirits C it as a win-win arrangement of course! Human hugs and CO2 rich songs of appreciation would be required to maintain the universal laws of equilibrium.(time for bed me thinks)
not rated yet Nov 02, 2010
but can this "glow in the dark" mechanism not be done just as well through genetic engineering WITHOUT any gold, as it has been done in laboratory for some animals...

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