Understanding the Origin of Surface Plasmon Resonance Microscopy Signals in Cell-Based Molecular Interaction...

Area of Science:

• Biophysics
• Cell Biology
• Microscopy

Background:

• Surface plasmon resonance microscopy (SPRM) is a key technique for label-free imaging of cell membrane biomolecular interactions.
• Distinctive SPRM patterns like edge-dominated signals and heterogeneous binding kinetics lack clear physical explanations.
• Current SPRM methods alone cannot fully resolve the origins of these observed cellular features.

Purpose of the Study:

• To elucidate the physical origins of SPRM signal patterns observed in cell-based assays.
• To investigate the relationship between local membrane features and binding kinetics heterogeneity.
• To provide a clearer understanding of SPRM signal formation at cellular interfaces.

Main Methods:

• Integration of surface plasmon resonance microscopy (SPRM) with depth- and time-resolved confocal fluorescence imaging.
• Utilized lectin binding on fixed cells as a model system for cellular interface studies.
• Correlated SPRM data with confocal imaging to analyze spatial and temporal binding dynamics.

Main Results:

• SPRM signals predominantly arise from ligand binding within the membrane region accessible to the evanescent field.
• Binding-induced membrane deformation contributes to the overall SPRM signal.
• Local membrane topography and features show a strong correlation with observed kinetic heterogeneity during binding.

Conclusions:

• The study provides direct experimental evidence clarifying SPRM signal formation in cell-based measurements.
• Offers practical guidance for improved quantification and interpretation of label-free plasmonic imaging data.
• Enhances understanding of biomolecular interactions at cellular interfaces using combined imaging techniques.