Abstract : Nonradiative Excitation Fluorescence Microscopy (NEFM) is a promising technique allowing the observation of biological samples beyond the diraction limit. By coating a substrate with an homogeneous monolayer of quantum dots (QDs), NEFM is achieved through a nonradiative energy transfer from QDs (donors) to dye molecules located in the sample (acceptors). The excitation depth of the sample is then given by the För-ster radius, which corresponds to few nanometers above the surface. The powerful axial resolution of NEFM is highlighted by observing the adhesion of Giant Unilamellar Vesi-cles (GUVs) on strong interaction with coated surfaces. In this paper, we demonstrate that the QD-quenching level is valuable to calculate and map the distance between the membrane and the surface with a high precision along the optical axis. By tuning the electrostatic interactions between the membrane and the substrate, we have been able to measure a height displacement of ≈ 1 nm of the lipid membrane. The experimental results were discussed according to simulations, which take into account all the common forces appearing between lipid membranes and surfaces.
https://hal-utt.archives-ouvertes.fr/hal-02363346 Contributor : Cyrille VEZYConnect in order to contact the contributor Submitted on : Thursday, November 14, 2019 - 1:28:58 PM Last modification on : Sunday, June 26, 2022 - 4:44:03 AM Long-term archiving on: : Saturday, February 15, 2020 - 3:05:22 PM