Colorimetric logic gates through molecular recognition and plasmonic nanoparticles.

A colorimetric logic system capable of AND, OR, INHIBIT and AND + OR logic operations is constructed. The principle is modulation of the distance between arginine (lysine)-modified gold nanoparticles via metal ions. A lab-on-chip format for the assembly of versatile logic gates is demonstrated as a proof of concept. These logic gates allow a straightforward readout by the naked eye.