How squid and octopus might point the way to nanotechnology-based stealth coatings

For a long time, scientists have been fascinated by the dramatic changes in color used by marine creatures like squids and octopuses, but they never quite understood the mechanism responsible for this. Only recently they found out that a neurotransmitter, acetylcholine, sets in motion a cascade of events that culminate in the addition of phosphate groups to a family of unique proteins called reflectins. This process allows the proteins to condense, driving the animal's color-changing process. The latest findings revealed that there is a nanoscale mechanism behind cephalopods' ability to change color.

Having begun to unravel the natural mechanisms behind these amazing abilities, researchers are trying to use this knowledge to make artificial camouflage coatings. Researchers from the University of California address the challenge of making something appear and disappear when visualized with standard infrared detection equipment. The research team demonstrates graphene-templated, biomimetic camouflage coatings that possess several important advantages. They used reflectin, a protein that is important for cephalopod structural coloration, as a functional optical material. They fabricated thin films from this protein, whose reflectance – and coloration – could be dynamically tuned over a range of over 600 nm and even into the infrared (in the presence of an appropriate stimulus). This approach is environmentally friendly and compatible with a wide range of surfaces, potentially allowing many simple objects to acquire camouflage capabilities. The novelty of these findings lies in the functionality of the team's thin-films within the infrared region of the electromagnetic spectrum, roughly 700nm to 1200nm, which matches the standard imaging range of infrared visualization equipment. This region is not commonly accessible to biologically derived materials. These dynamically tunable, infrared-reflective films represent a crucial first step towards the development of reconfigurable and disposable biomimetic camouflage technologies for stealth applications.

(http://www.nanowerk.com/spotlight/spotid=31796.php)

CONTROLLED PRACTICE

I. Choose the correct option and answer the questions using the text of the article.

1. Find the synonym to the word “to condense” (according to the context of the article)

A to change

B to thicken

C to reduce

2. What does neurotransmitter mean?

A an electrical impulse in a nerve cell

B a chemical that carries messages from nerve cells to other nerve cells or muscles

C a protein responsible for color-changing

3. Find the synonym to the word “to expose to” (according to the context of the article)

A to treat with something harmful

B to show

C to uncover something

D to film

4. What protein is important for cephalopod structural coloration?

A fibrin

B albumin

C reflectin

D gluten

5. How do cephalopods change color?