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.