Photonic crystal surface mode imaging biosensor based on wavelength interrogation of resonance peak

•A new imaging biosensor technique based on photonic crystal surface modes (PCSMs) is presented.•The spectral shift of the PCSM resonance peak is detected by a standard color camera at each point of the PC chip surface.•The dynamic range of the biosensor in the adsorbate layer thickness is 150 nm and the baseline noise is 3.5 pm.•The first experiments using the device showed that the proposed imaging method can surpass its plasmonic analog (SPRi) with respect to both signal-to-noise ratio and dynamic range.