Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 59: Poster Session II (Nanostructures at surfaces: Dots, particles, clusters; Nanostructures at surfaces: arrays; Nanostructures at surfaces: Wires, tubes; Nanostructures at surfaces: Other; Plasmonics and nanooptics; Metal substrates: Epitaxy and growth; Metal substrates: Solid-liquid interfaces; Metal substrates: Adsoprtion of organic / bio molecules; Metal substrates: Adsoprtion of inorganic molecules; Metal substrates: Adsoprtion of O and/or H; Metal substrates: Clean surfaces; Density functional theory and beyond for real materials)

O 59.28: Poster

Mittwoch, 24. März 2010, 17:45–20:30, Poster B1

Nanoparticle-based Photothermal Control of the Catalytic Activity of the Enzyme HRP — Jan Bretschneider¹, Maximilian Reismann², •Malte Linn², Gero von Plessen², and Ulrich Simon¹ — ¹Institute of Inorganic Chemistry, RWTH Aachen University, Germany — ²I. Inst. of Physics (IA), RWTH Aachen University, Germany

The optical excitation of particle plasmons in a gold nanoparticle by laser irradiation induces a temperature rise in the nanoparticle and its immediate surroundings. This effect can be exploited to control temperature-sensitive chemical reactions in a contactless and highly localized manner. In this work, this photothermal effect is utilized to control the catalytic activity of an enzyme. For this purpose, the enzyme horseradish peroxidase (HRP) is bound to the surface of gold nanoparticles which are suspended in water. The HRP catalyses the oxidation of the diazonium compound ABTS to ABTS⁺. A resonant excitation of the HRP-functionalized nanoparticles by cw-laser light with a wavelength of 532 nm leads to a heating of the nanoparticle environment.

We show that this photothermal heating reduces the rate of the catalytic conversion process. For this purpose, the reaction kinetics is spectroscopically monitored via a color change of the colorless reactant (ABTS) transformed into the greenish product (ABTS⁺).