title: Distance-Dependent Plasmon-Enhanced Singlet Oxygen Production and Emission for Bacterial Inactivation.
abstract: Herein, we synthesized a series of 10 core-shell silver-silica nanoparticles with a photosensitizer, Rose Bengal, tethered to their surface. Each nanoparticle possesses an identical silver core of about 67 nm, but presents a different silica shell thickness ranging from 5 to 100 nm. These hybrid plasmonic nanoparticles thus afford a plasmonic nanostructure platform with a source of singlet oxygen ((1)O2) at a well-defined distance from the metallic core. Via time-resolved and steady state spectroscopic techniques, we demonstrate the silver core exerts a dual role of enhancing both the production of (1)O2, through enhanced absorption of light, and its radiative decay, which in turn boosts (1)O2 phosphorescence emission to a greater extent. Furthermore, we show both the production and emission of (1)O2 in vitro to be dependent on proximity to the plasmonic nanostructure. Our results clearly exhibit three distinct regimes as the plasmonic nanostructure moves apart from the (1)O2 source, with a greater enhancement for silica shell thicknesses ranging between 10 and 20 nm. Moreover, these hybrid plasmonic nanoparticles can be delivered to both Gram-positive and Gram-negative bacteria boosting both photoantibacterial activity and detection limit of (1)O2 in cells.
authors: Institut Quimic de Sarria, Universitat Ramon Llull , Barcelona 08022, Spain.
authors: Oriol
authors: O
authors: Planas
authors: Department of Chemistry, University of Calgary , Alberta AB T2N 1N4, Canada.
authors: Nicolas
authors: N
authors: Macia
authors: Institut Quimic de Sarria, Universitat Ramon Llull , Barcelona 08022, Spain.
authors: Montserrat
authors: M
authors: Agut
authors: Institut Quimic de Sarria, Universitat Ramon Llull , Barcelona 08022, Spain.
authors: Santi
authors: S
authors: Nonell
authors: Department of Chemistry, University of Calgary , Alberta AB T2N 1N4, Canada.
authors: Belinda
authors: B
authors: Heyne
mesh_terms: D004926:Escherichia coli / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D053768:Metal Nanoparticles / Q000737:chemistry*; D017319:Photosensitizing Agents / Q000138:chemical synthesis / Q000737:chemistry; D012395:Rose Bengal / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D026082:Singlet Oxygen / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D013211:Staphylococcus aureus / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D020349:Surface Plasmon Resonance / Q000379:methods*
chemical_list: D017319:Photosensitizing Agents; D026082:Singlet Oxygen; D012395:Rose Bengal; D012834:Silver