Color-changing polymer maps fingerprints

Detecting perspiration pinpoints people’s pores

SWEAT PRINT  Tiny pores on people’s fingertips ooze sweat droplets (shown red in fluorescence image) that can be detected with a new color-changing polymer. The technique could supplement traditional fingerprinting methods, which rely on impressions left by finger ridges.

Courtesy of Kim et al

Sweaty fingers make tidy prints. Beads of perspiration seeping from a person’s pores can leave detailed maps of the fingertips, and a new technique can detect the sweat.