title: Characterization of Porous Materials by Fluorescence Correlation Spectroscopy Super-resolution Optical Fluctuation Imaging.
abstract: Porous materials such as cellular cytosol, hydrogels, and block copolymers have nanoscale features that determine macroscale properties. Characterizing the structure of nanopores is difficult with current techniques due to imaging, sample preparation, and computational challenges. We produce a super-resolution optical image that simultaneously characterizes the nanometer dimensions of and diffusion dynamics within porous structures by correlating stochastic fluctuations from diffusing fluorescent probes in the pores of the sample, dubbed here as "fluorescence correlation spectroscopy super-resolution optical fluctuation imaging" or "fcsSOFI". Simulations demonstrate that structural features and diffusion properties can be accurately obtained at sub-diffraction-limited resolution. We apply our technique to image agarose hydrogels and aqueous lyotropic liquid crystal gels. The heterogeneous pore resolution is improved by up to a factor of 2, and diffusion coefficients are accurately obtained through our method compared to diffraction-limited fluorescence imaging and single-particle tracking. Moreover, fcsSOFI allows for rapid and high-throughput characterization of porous materials. fcsSOFI could be applied to soft porous environments such hydrogels, polymers, and membranes in addition to hard materials such as zeolites and mesoporous silica.
authors.forename: Lydia
authors.initials: L
authors.lastname: Kisley
authors.affiliation: Department of Physics, Scripps College , Claremont, California 91711, United States.
authors.forename: Rachel
authors.initials: R
authors.lastname: Brunetti
authors.forename: Lawrence J
authors.initials: LJ
authors.lastname: Tauzin
authors.forename: Bo
authors.initials: B
authors.lastname: Shuang
authors.forename: Xiyu
authors.initials: X
authors.lastname: Yi
authors.affiliation: Department of Chemistry, Kansas State University , 213 CBC Building, Manhattan, Kansas 66506-0401, United States.
authors.forename: Alec W
authors.initials: AW
authors.lastname: Kirkeminde
authors.affiliation: Department of Chemistry, Kansas State University , 213 CBC Building, Manhattan, Kansas 66506-0401, United States.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Higgins
authors.forename: Shimon
authors.initials: S
authors.lastname: Weiss
authors.forename: Christy F
authors.initials: CF
authors.lastname: Landes
keywords: correlation; diffusion; fluorescence microscopy; hydrogel; liquid crystal; super-resolution