Fluorescence Phase Microscopy (FPM) and Nanoscopy - Biomedical Optical Phase Microscopy and Nanoscopy - page 386

Figure 18.7
(A) A single shot depth profile of the fluorescently labeled embryonic nervous system of Drosophila
measured by SD-FPM. Intensity and gradient images are shown. (B) 3D views of the fluorescently
labeled nervous system of the Drosophila embryo imaged by the TD-FPM system. (C) Wide-field
images of fluorescently labeled endothelial cells captured by the TD-FPM system (left) and by a
conventional wide-field fluorescence microscope (right) employing identical low-aperture
objectives. Sharper details can be detected by TD-FPM due to the coherence gate mechanism
which assists in rejecting out-of-focus fluorescence.

TIRF-based SD-FPM system shown in Figure 18.3B which localizes single QDs attached to
the bilayers with nanometer-level accuracy in all 3D. Figure 18.8A shows that QDs
attached to a six-bilayer substrate underwent an axial displacement of 20 5 nm, whereas

the lateral displacement was determined with a lateral localization precision below 10 nm.
The axial displacement was comparable to that measured by surface plasmon resonance
(SPR); yet, the TIRF-based SD-FPM system is advantageous over SPR systems as it can
also identify lateral nano-displacements across a large field of view.

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