Interpretation of Solution X-Ray Scattering Data by Molecular Dynamics

from electron damage. The sample, tagged with organic dyes, is placed on a scintillating cerium-doped yttrium aluminum perovskite (YAP) film. A focused electron beam is then used to generate optical excitations at a specific location on the film opposite the sample, thus forming a 20-nm illumination volume that excites fluorophores. Dye fluorescence is collected within the electron microscope and, as the beam is scanned, an image is formed. In order to completely block a low-voltage electron beam yet maximize the optical excitation intensity, an extremely thin YAP film is required. We have succeeded in fabricating a 20-nm thick suspended YAP film over an area 30 microns wide via molecular beam epitaxy, pulsed laser deposition, and deep reactive ion etching. Using our ultrathin scintillating films, we demonstrate superresolution imaging of fluorescently labeled particles and polymers. This technique has the potential to revolutionize correlative microscopy by combining a scanned electron probe with fluorescence detection in the same instrument, at the same time. In general, due to its nondestructive nature, it holds great promise as an alternative multiscale fluorescence microscopy, with resolution tunable from tens of nanometers up to microns, especially for damage-sensitive or highly dynamic cellular structures. We are applying this tool toward the study of biologically-inspired nanostructures, thylakoid membrane organization, and molecular motor dynamics.