Plasmonic nanoprobes for biomedical applications

Vietsciences-Vũ Xuân Hòa      18/10/2013 


Institute of physics
Centre for quantum electronics

Tiêu đề / Title:
Plasmonic nanoprobes for biomedical applications
Người trình bày / Speaker:
Dr. Vũ Xuân Hòa
Department of Physics, Faculty of Science
Chulalongkorn university, Bangkok

Thời gian / Time:
10g00, Thứ Sáu, 25-10-2013
(10:00 AM, Friday, 25 October 2013)

Địa điểm / Venue:
Phòng 63, nhà 2H, Viện Vật lý, 18 Hoàng Quốc Việt, Hà Nội
 (Room 63, Building 2H, Institute of physics, 18 Hoàng Quốc Việt, Hà Nội)
Tóm tắt / Abstract
   Abstract : Gold nanoparticles have remarkable optical properties due to their plasmon resonance. At resonance, their absorption and scattering cross-sections can be larger than their geometric section. This opens the way to many applications especially in the biomedical field. For example it is possible to track a single nanoparticle by its scattered signal, or use it as a source efficient photothermal transducer. In the first part, we have developed gold nanoparticles with half-sphere shaped, called nanocrescents, by nanosphere lithography. This reproducible technique allows the production of monodisperse nanocrescents, possibly incorporating other additional  properties. In particular, we designed hybrid nanoprobes combining magnetic properties or fluorescence plasmonic properties. The anisotropic shape of nanocrescents gives them anisotropic optical properties that have the signature of their orientation. In a second part, we have developed a technique to measure local temperature from correlations of the scattered light from an individual nanocrescent under dark field microscopy. The rotational Brownian motion of the nanoparticle gives access to the temperature of the immediate environment.
Finally, in the third part, we have developed a photothermic setup using a laser that coincides with one of the plasmon resonances of the nanocroissants. These latter behave as nano-heater. The local increase of temperature was measured remotely, with an accuracy of approximately one degree, using the scattering correlation spectroscopy.

Keywords: plasmon, nanoparticle, nanocrescent, temperature, Brownian motion, scattering correlation spectroscopy.

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