International Business Machines Corporation
Covert codes based on electrical sensing of patterned materials in microfluidic devices

Abstract:

A microfluidic device includes a surface, which defines a flow path for a liquid, and a liquid inlet, which is in fluid communication with said surface, so as for a liquid introduced via the inlet to advance along a propagation direction on the flow path. Also included are a set of two or more electrical contacts, and a set of electrodes which include sensing portions that extend across the flow path, transversally to the propagation direction. The electrodes are connected to the two or more electrical contacts. Also included are material spots on at least some of the sensing portions of the electrodes. Still, material spots of a same material are only on a subset of the sensing portions of the electrodes, so that the spots can alter an electrical signal detected from the electrical contacts, upon a liquid advancing along the flow path, in operation of the device.