Light emitting diode antifuses have been integrated into a microfluidic device that is realized with extended standard IC-compatible technological steps. The device comprises a microchannel sandwiched between a photodiode detector and a nanometre-scale diode antifuse light emitter. In this paper, the device fabrication process, working principle and properties and possible applications will be discussed. Changes in the interference fringe of the antifuse spectra due to the filling of the channel have been measured. Potential applications are electro-osmotic flow speed measurement, detection of absorptivity of liquids in the channel, detection of changes of the refractive index of the medium in the channel, e.g. air bubbles, particles in the liquid.