Chameleons colour changing secret discovered to be nanotechnology!

Chameleons are one of natures most incredible creatures with their ability to quickly change colour for social reasons or personal protection.

They have populated myths and legends and were even described by Aristotle due to their unusual features including their independently moveable eyes, long projectile tongue and zygodactylous (two toes forward, two behind) feet.

Previously it was thought that chameleons changed colour through pigments in their skin, but this week research published in Nature communications revealed its actually through nano-photonic crystals found in a layer of cells called iridophores which lie below the chameleons pigment cells.

So chameleons have been secretly using nanotechnology all along!   I knew I liked them for a reason!

Transmission Electron Microscope images of the lattice of guanine nanocrystals in iridophores from the same chameleon in a relaxed and excited state. The relaxed state has a higher crystal density resulting in reflection of blue light wavelengths, the less dense excited state results in red and yellow light wavelength reflection. Adapted image source

Transmission Electron Microscope images of the lattice of guanine nanocrystals in iridophores from the same chameleon in a relaxed and excited state. The relaxed state has a higher crystal density resulting in reflection of blue light wavelengths, the less dense excited state results in red and yellow light wavelength reflection. Adapted image source

Iridophores are not new and they are found in other reptiles and amphibians resulting in the blue and green colours that are not often found in vertebrates, but the difference is that chameleons have lattices of these nanocrystals which they can tune to alter the way that the light is reflected.

If the chameleon is calm, the crystals are organised into a dense network which reflect the blue wavelengths of incoming light.

If the chameleon is excited, it loosens the dense lattice and this allows the reflection of yellow and red wavelengths.

The study also discovered that chameleons have a deeper layer of iridophore cells which contain larger and less ordered crystals which reflect infrared wavelengths from sunlight.  This  protects the chameleon from the heat of the strong sun by arming them with a natural heat shield.

Scientists still don’t understand the mechanism behind how the chameleon fine tunes the nanocrystals but this new research can help with alternative ways to protect man made object from high heat sources.

To hear more on my views on this new finding, click here to listen to my Radio Live chat with Mark Sainsbury

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