High-performance compact SPR sensor for multi-analyte sensing

We present a novel compact surface plasmon resonance (SPR) sensor capable of simultaneous detection of up to 10 analytes. The sensor is based on angular interrogation of SPR on a gold-coated diffraction grating contained in a disposable sensor cartridge with 10 independent fluidic channels. Parameters affecting the sensor performance such as operating wavelength, the angle of incidence and the depth and period of the diffraction grating were optimized in order to achieve a sensor resolution comparable with the top laboratory instruments while keeping the optical system at a compact size. The developed sensor prototype was tested in a refractometric experiment and its resolution was determined to be 6 × 10−7 RIU. The sensor's potential to simultaneously detect multiple samples was demonstrated in an experiment where samples containing short oligonucleotides of different concentrations were detected. The limit of detection was determined to be below 1 nM.