We've seen a number of efforts to build a better artificial skin, or "e-skin," over the years, and a team of researchers from the Technion-Israel Institute of Technology now say they've made a breakthrough that could lead to some of the most sensitive e-skin yet. The key development is a new type of flexible sensor that would not only allow the artificial skin to detect touch, but humidity and temperature as well. Those sensors are comprised of gold-based nanoparticles that are just five to eight nanometers in diameter and laid on top of a substrate -- in their research, the scientists used PET, the type of plastic you'd normally find in soda bottles. That substrate conducts electricity differently depending on the way it is bent, which means researchers can adjust its sensitivity just by increasing its thickness. As you might expect, this is all still in the early stages, but the researchers see plenty of possibilities for the future, from bringing a sense of touch to artificial limbs to using the same technology to monitor stress on bridges.