Under electrical excitation the polymer emits light via radiative combination of injected electrons and holes and therefore may be used as a light source. The same structure can then be used in reverse as a photodetector by illuminating the polymer in order to generate a measurable electrical current.
The reagents of an assay will be mixed with the body fluid through the microfluidic network. The resulting mixture will be excited by the integrated, battery driven pLED and the resulting light-signal will be detected by the integrated photodetector which will generate an electrical current (electronic readout).

Schematic of pLED and photodetector integrated into microfluidic chip