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ancient world Science technology

Nanotechnology in Ancient Times

“According to a 2000-year-old recipe for hair dye, the ancient Greeks and Romans were harnessing a scientific force that they had no idea even existed – they were using nanotechnology on their very own heads.
The Greeks and Romans used hair dye with some measure of frequency, most often for the purpose of dying their gray hair to black. Their dry mixture contained ingredients such as slaked lime and lead oxide, which – when exposed to human hair for approximately 3 days – causes nanocrystals made from lead sulfide to form inside the shaft of hair.
This reaction is caused when sulfur from the amino acids that are naturally present in hair keratins mix with the lead in lead oxide – initially, this is what causes the hair to turn black, but it apparently also causes lead sulfide nanocrystals that are highly similar to those found in modern, advanced scientific processes!
In simpler terms, the chemical compound that forms inside of the human hair is what colors the hair without damaging it – and the process by which the hair is dyed black is very similar to modern nanotechnology. Fortunately for the Greeks and Romans, this kind of lead-based hair dye is safe for human use, since the compound typically has trouble penetrating the skin.
Interestingly enough, the chemical engineering that came from this dye process – where the tiny crystal structures line up to form ‘quantum dots‘ – is something that scientists have admitted is a “current challenge in nanotechnology”, and is actually a process that researchers are currently trying to figure out how to develop on their own.”

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quantum dots picture
These substances were colored by quantum dots in a modern laboratory. The principle at work is related to that used in ancient hair dye
Categories
technology

Nanotech in Nature: Gecko Feet

“Scientists have long been interested in the ability of gecko lizards to scurry up walls and cling to ceilings by their toes.
The creatures owe this amazing ability to microscopic branched elastic hairs in their toes that take advantage of atomic-scale attractive forces to grip surfaces and support surprisingly heavy loads. Several research groups have attempted to mimic those hairs with structures made of polymers or carbon nanotubes…
‘The resistance to shear force keeps the nanotube adhesive attached very strongly to the vertical surface, but you can still remove it from the surface by pulling away from the surface in a normal direction,’ “

gecko foot hairs
Gecko foot hairs under a scanning electron microscope.