Surface plasmon resonance spectro-imaging sensor and associated data processing for biomolecular surface interaction characterization

Surface plasmon resonance (SPR) technique has become over the last ten years a powerful tool allowing the analysis and the detection of biomolecular surface interactions in real time without any use of labels. The highest sensitivity is currently obtained using a mono-spot sensor through the measurement of the complete surface plasmon resonance curve (in angular or spectral configuration), since it is inherently more robust than a single intensity variation measurement. However, this last approach is used to perform SPR imaging, allowing parallel monitoring of hundreds of sensing spots onto a camera. We present in this work a SPR spectro-imaging system including dynamical multi-spectral capabilities. The system is based on the illumination over a vertical slit of the biochip (y-dimension) by a white light source. The spectrum of the reflected light obtained through a grating is then imaged on the x dimension of the camera. The complete spectral resonance curve of a full column of sensing spots can be monitored in parallel and in real-time by this simple apparatus. The influence of the main instrumental parameters and of different data processing are investigated. Clear improvements of the sensitivity have been obtained on refractometric tests and preliminary results on DNA:DNA interactions are finally presented.