Label-free quantification of cell-to-substrate separation by surface plasmon resonance microscopy

We study surface plasmon resonance microscopy (SPRM) for label-free quantification of cell-to-substrate separation. We have established a depth extraction model in which we compare a layered cell substrate model with resonance characteristics obtained by SPRM. We have applied the model to human aortic endothelial cell (HAEC) culture and determined the separation distance to be 40-60 nm. We have also investigated the precision of the SPRM model associated with the deviation in the model parameters, which is estimated to be 15 nm. The results can serve as the basis for more extensive cell-to-surface studies in a massive and automated way.