Amplified Production of Singlet Oxygen in Aqueous Solution Using Metal Enhancement Effects

Abstract

Studies involving metal enhancement effects have gained popularity, and enhancement of fluorescence due to the close proximity of a dye molecule to a metal nanoparticle is well documented. Although enhancement of singlet oxygen production by metal has been reported, studies are relatively scarce and so far only stationary silver island films have been proven to be adequate to do so. Herein, we describe the synthesis and characterization of core-shell nanoparticles on which a photosensitizer acting as source of singlet oxygen has been covalently attached to the nanoparticle surface. As a proof of concept, silver nanoparticles with a diameter around 68 nm were chosen as the metallic core, and were coated by a silica shell of about 22 nm in thickness. The silica shell plays a dual role as a spacer and a medium onto which the photosensitizer, rose bengal (RB), has been covalently attached. These novel core-shell nanoparticles allow for the amplification of singlet oxygen production by 3.8 times, which is similar to the amplification found for RB in proximity of silver island films.

Gold Nanoparticle Mediated Phototherapy for Cancer

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Photosensitization of Molecular Oxygen on Graphene Oxide for Ultrasensitive Signal Amplification

“…Direct catalytic oxidationo fT MB by molecularo xygen is analogous to the oxidasea ctivity.C urrently,f ew oxidasee nzymes are used in ELISAa ssays.C ompared with some reported oxidasem imics (e.g.,C eO 2 nanoparticles [12] ), photosensitizers are advantageous in terms of their reproducibility,s tructural tunability, [13] andm uch smaller size.…”

Using photochemistry to understand and control the production of reactive oxygen species in biological environments

“…Using this strategy, our group recently reported the synthesis of new multilayer core-shell Ag-silica MNPs onto which a photosensitizer was covalently attached. [138] In our study, a silica shell thickness of about 22 nm afforded the optimal separation between the Ag-core MNPS (68 nm) and the photosensitizer, Rose Bengal. [138] These new MNPs lead to the highest 1 O 2 enhancement factor (ca.…”

“…[138] In our study, a silica shell thickness of about 22 nm afforded the optimal separation between the Ag-core MNPS (68 nm) and the photosensitizer, Rose Bengal. [138] These new MNPs lead to the highest 1 O 2 enhancement factor (ca. 4) ever reported for MNP-photosensitizer systems.…”