Peter Parker's secret webbing formula, which has to be strong enough to support his weight when he goes web-swinging, is closer to reality than ever. Although spider silk is already proportionally stronger than steel cable, scientists have found a way to increase its tensile strength up to ten times more by injecting it with metal:

They tried zinc, aluminium and titanium compounds, all of which improved the mechanical properties of the silk. "With all three metals, the fibres can hold three to four times as much weight," says Knez. The fibres also become stretchier, so that their toughness - the energy needed to break a strand - rises even more. "The work needed to break the fibre rises tenfold with titanium, ninefold with aluminium and fivefold with zinc," he says.

(New Scientist)