Glass chip spins silk

Inside the chip, the two proteins flow along tiny tubes and are exposed to a phosphate salt solution that makes them aggregate into tiny spheres 1 to 5 micrometres across.

A sudden jump in acidity and phosphate concentration then partially breaks open the spheres, allowing the proteins to latch together into chains. At this point, the flow speed increases and draws out the proteins into long silk fibres.

Creating fibres from two proteins was found to make the silk more chemically stable. The team has not tested the artificial silk's mechanical properties, but its grainy appearance suggests it does not yet rival the quality of the real thing.