Protein conformation characterization via a silicon resonator-based optical sensor based on the combination of wavelength interrogation and dual polarization detection

Protein conformational abnormality causes cell malfunction. Conformational change of amyloid protein causes neuron malfunction, which renders “protein conformational disease” Alzheimer’s disease. Dual polarization interferometry enables to provide one-dimensional structure of a protein biolayer via deconvolution of interference patterns, which in turn is interpreted as the protein molecule conformation. However, it is still challenging to avoid interference patterns becoming faint and obscure sometimes. Resonance wavelength response to the biolayer structure can achieve a very low detection limit due to inherent high Q factor of an optical resonator. Here, we introduce the concept of combining dual polarization detection with wavelength interrogation via a simple and compact resonator-based optical biosensor. Biolayer were probed by the wave of dual polarization and its opto-geometrical parameters were resolved into resonance wavelength shift. Because protein molecule with distinct conformation produced a biolayer with unique thickness and mass density. Amyloid proteins in monomeric and dimeric morphology were respectively characterized. This concept enables protein conformation characterization in an easy and direct paradigm and provides a desirable sensing performance due to sensitive resonance response in the form of the sharp resonance profile occurring in a nonoverlapping spectrum.