Ancient Greek hairdressers could teach us a thing or two about nanotechnology.

When hair is dyed using a lead-based dye popular 2000 years ago, crystals of lead sulphide just 5 nanometres across form within the microstructure of the hair fibres, according to a team led by Phillipe Walter at the French Museums' Research and Restoration Centre in Paris.

A hair-like scaffold could be used to grow "quantum dots" - tiny crystals which confine a handful of electrons in a way that makes it possible to exploit their quantum properties, such as spin, for use in emerging quantum computing systems. Existing methods for producing quantum dots create defects. The work will be reported in Nano Letters.