A Chalmers University (Sweden) research group lead by Fredrik Höök has applied Surface-Enhanced Ellipsometric Contrast (SEEC) microscopy for time-resolved, label-free visualization of biomolecular recognition events on spatially heterogeneous, supported lipid bilayers (SLB).
Biomolecular binding events were monitored with a lateral resolution near the optical diffraction limit at an acquisition rate of ~1 Hz with a sensitivity in terms of surface coverage of ~1 ng/cm². Despite the signifcant improvement in spatial resolution compared to alternative label-free surface-based imaging technologies, the sensitivity remains competitive with surface plasmon resonance (SPR) imaging and imaging ellipsometry.
The potential of the technique to discriminate local differences in protein binding kinetics as well as its compatibility with microfluidic devices was demonstrated by time-resolved imaging of anti-GalCer antibodies binding to phase-separated lipid bilayers consisting of phosphatidylcholine (POPC, bright area) fluidic phase and galactosylceramide (GalCer, dark area) gel phase.
This feat was made possible thanks to T-Surfs from Nanolane, innovative contrast-enhancing slides specially designed for nanometric characterization with a conventional inverted reflected light microscope, which are intended to help study biological samples, biofilms, organic layers in liquid or in air. In addition, they are compatible with most of the current nano-analytical devices and instruments (microfluidics, Fluorescence, AFM,...).