title: Diffusion Reflection and Fluorescence Lifetime Imaging Microscopy Study of Fluorophore-Conjugated Gold Nanoparticles or Nanorods in Solid Phantoms.
abstract: In this paper we report the optical properties of fluorescein-conjugated gold nanoparticles (GNPs) in solid phantoms using diffusion reflection (DR) and fluorescence lifetime imaging microscopy (FLIM). The GNPs attached with fluorescein in solution were studied by fluorescence correlation spectroscopy. The intensity decays were recorded to reveal the fluorescence lifetime of fluorescein while in the near-field vicinity of the GNPs. The DR method was used to explore the solid phantoms containing GNPs, indicating the light propagation from the surface of solid phantoms. The resulting DR slopes of the reflected intensity showed the higher the GNP concentration, the bigger the slope. Fluorescence intensity, lifetime, and anisotropy images of solid phantoms were investigated by FLIM. The exploration of optical properties and molecular imaging combined with DR and FLIM methods is a new approach that has not been established until now. The combined DR-FLIM technique is expected to provide discrimination based on unique spectroscopic fingerprints of GNPs that could be utilized for cell imaging. This paper includes a combined study with a variety of methods, which may lead to multimodal imaging for surfaces (by FLIM) and deep penetration (up to cm by the DR) together.
authors.affiliation: Faculty of Engineering and the Institute of Nanotechnology and Advanced Materials, Bar Ilan University , Ramat Gan 5290002, Israel.
authors.forename: Dror
authors.initials: D
authors.lastname: Fixler
authors.affiliation: Faculty of Engineering and the Institute of Nanotechnology and Advanced Materials, Bar Ilan University , Ramat Gan 5290002, Israel.
authors.forename: Tsviya
authors.initials: T
authors.lastname: Nayhoz
authors.affiliation: Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine , Baltimore, Maryland 21201, United States.
authors.forename: Krishanu
authors.initials: K
authors.lastname: Ray
keywords: biomolecular imaging; diffusion reflection; fluorescence anisotropy; fluorescence lifetime imaging; gold nanoparticles; noninvasive detection