title: Decreasing photobleaching by silver nanoparticles on metal surfaces: application to muscle myofibrils.
abstract: Recently it has become possible to study single protein molecules in a cell. However, such experiments are plagued by rapid photobleaching. We recently showed that the interaction of fluorophores with localized surface plasmon polaritons (LSPs) induced in the metallic nanoparticles led to a substantial reduction of photobleaching. We now investigate whether the photobleaching could be further reduced when the excited fluorophore interacts with the LSP excited in the metallic nanoparticles resident on mirrored surface. As an example we use myofibrils, subcellular structures within skeletal muscle. We compare nanoparticle-enhanced fluorescence of myofibrils in the presence and in the absence of a mirrored surface. The proximity of the mirrored surface led to enhancement of fluorescence and to a decrease in fluorescent lifetime, much greater than that observed in the presence of nanoparticles alone. We think that the effect is caused by the near-field interactions between fluorophores and LSP, and between fluorophores and propagating surface plasmons (PSPs) produced in the metallic surface by the nanoparticles. Photobleaching is decreased because fluorescence enhancement enables illumination with a weaker laser beam and because the decrease in fluorescence lifetime minimizes the probability of oxygen attack during the time a molecule is in the exited state.
authors.affiliation: University of North Texas Health Science Center, Department of Molecular Biology and Immunology, Center for Commercialization of Fluorescent Technology, Fort Worth, Texas 76107, USA.
authors.forename: Priya
authors.initials: P
authors.lastname: Muthu
authors.forename: Ignacy
authors.initials: I
authors.lastname: Gryczynski
authors.forename: Zygmunt
authors.initials: Z
authors.lastname: Gryczynski
authors.forename: John M
authors.initials: JM
authors.lastname: Talent
authors.forename: Irina
authors.initials: I
authors.lastname: Akopova
authors.forename: Julian
authors.initials: J
authors.lastname: Borejdo
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods; D007089:Image Enhancement / Q000379:methods; D008856:Microscopy, Fluorescence / Q000379:methods*; D009124:Muscle Proteins / Q000032:analysis*; D009210:Myofibrils / Q000378:metabolism* / Q000648:ultrastructure*; D053758:Nanoparticles; D038761:Photobleaching; D011817:Rabbits; D012834:Silver; D020349:Surface Plasmon Resonance / Q000379:methods*
chemical_list: D009124:Muscle Proteins; D012834:Silver