We report a method enabling intensity-based readout for label-free cellular assays
and realize a reader device with the same footprint as a microtiter plate. For unambiguous
resonance intensity measurements in resonance waveguide grating (RWG) sensors, we
propose to apply resonances near the substrate cutoff wavelength. This method was
validated in bulk refractive index, surface bilayer and G protein-coupled receptor
(GPCR) experiments. The significantly reduced size of the reader device opens new
opportunities for easy integration into incubators or liquid handling systems.
