Gold nanoparticles (GNPs) are excellent materials for theranostic applications because of their excellent biocompatibility, their adaptable preparation to obtain the desired morphological features, and their facile surface chemistry, which allows easy functionalization for specific targeting of biomolecules. Additionally, at the nanometric scale, gold exhibits new interesting physical and optical properties. In this size range, incident light under appropriate conditions induces the collective resonant excitation of the free electrons on the metal surface (localized surface plasmon resonance -LSPR), which gives rise to a strong absorption with molar extinction coefficients 105 times higher than those of conventional dyes. Even more interestingly, after excitation of the surface plasmon, the adsorbed energy can be dissipated by coupling to atomic lattice vibrations (phonons) and the following phonon-phonon relaxation in the picosecond time scale brings about the release of heat in the surrounding media (photothermal effect) that is capable of destroying nearby biological structures.Gold nanostructures (GNSs) have been tested for different applications; many of these applications are based on the unique property of GNSs to act as an efficient signal transducer able to convert visible or near-infrared (NIR) radiation into heat, which diffuses in the medium where the nanostructures are dispersed, originating the so-called photothermal effect. The present chapter is divided into three main sections. The first is an introduction to the photophysical behavior of GNSs. The second is a short review of the experimental procedures used to tune the optical properties of GNSs; the third is a description of the application of the photothermal effect in the biomedical field, with many examples from the most recent literature. The photophysical properties of GNSs are then introduced with the aim of giving a rational description of the photothermal effect that highlights the importance of absorption cross sections and hence accounts for the efforts made to tune the optical properties of GNSs during synthesis. The last section describes in detail the application of the photothermal effect as a powerful tool for altering and destroying selected cells. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA. All rights reserved.
Photothermal Effect of Gold Nanostructures for Application in Bioimaging and Therapy
LATTERINI, Loredana;TARPANI, LUIGI
2014
Abstract
Gold nanoparticles (GNPs) are excellent materials for theranostic applications because of their excellent biocompatibility, their adaptable preparation to obtain the desired morphological features, and their facile surface chemistry, which allows easy functionalization for specific targeting of biomolecules. Additionally, at the nanometric scale, gold exhibits new interesting physical and optical properties. In this size range, incident light under appropriate conditions induces the collective resonant excitation of the free electrons on the metal surface (localized surface plasmon resonance -LSPR), which gives rise to a strong absorption with molar extinction coefficients 105 times higher than those of conventional dyes. Even more interestingly, after excitation of the surface plasmon, the adsorbed energy can be dissipated by coupling to atomic lattice vibrations (phonons) and the following phonon-phonon relaxation in the picosecond time scale brings about the release of heat in the surrounding media (photothermal effect) that is capable of destroying nearby biological structures.Gold nanostructures (GNSs) have been tested for different applications; many of these applications are based on the unique property of GNSs to act as an efficient signal transducer able to convert visible or near-infrared (NIR) radiation into heat, which diffuses in the medium where the nanostructures are dispersed, originating the so-called photothermal effect. The present chapter is divided into three main sections. The first is an introduction to the photophysical behavior of GNSs. The second is a short review of the experimental procedures used to tune the optical properties of GNSs; the third is a description of the application of the photothermal effect in the biomedical field, with many examples from the most recent literature. The photophysical properties of GNSs are then introduced with the aim of giving a rational description of the photothermal effect that highlights the importance of absorption cross sections and hence accounts for the efforts made to tune the optical properties of GNSs during synthesis. The last section describes in detail the application of the photothermal effect as a powerful tool for altering and destroying selected cells. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
