Application Note: Label-free Ligand Fishing in Human Plasma Using Surface Plasmon Resonance and Mass Spectrometry Imaging
18 May 2011

In this application note by HORIBA, SPR imaging coupled to MALDI-MS is used as an approach to detect LAG3 recombinant protein in plasma. The solution fraction of this protein is a potential biomarker for breast cancer. A mouse antibody (IgG2A) directed against LAG3 was immobilized on a SPRi-Slide using a dedicated surface chemistry compatible with MS analysis (NHS chemistry). The specific interaction of LAG3 and IgG2A was monitored using SPRi and images of the interaction were studied. The SPRi-Slide was analyzed using a MALDI-MS imager. By showing the distribution of MS peaks specific of LAG3, it was possible to build the MS image of LAG3 spots directly on the SPRi-Slide.