Thermoplasmonic Effects in Gain-Assisted Nanoparticle Solutions

Abstract

We report a detailed characterization of the photoinduced heating observed in gain-assisted solutions of gold nanoparticles (AuNPs). AuNPs, with sizes ranging from 14 to 48 nm and concentration of 2.5 × 10–10 M, are exposed to different intensity values of a resonant continuous laser (532 nm), used to excite their localized surface plasmon resonance (LSPR), responsible for the photogeneration process. In this way the optimal conditions to achieve the maximum temperature variation with the least laser dosage are obtained. By addition of an organic dye to the solutions, whose emission band overlaps to the LSPR, we found that the contribution to the photothermal efficiency is enhanced if the solutions are excited at 405 nm. This happens in the case of smaller NPs, due to a strong coupling effect between the two subunits, which causes an increase of the extinction cross section of the whole gain-assisted system. On the other hand, for the larger AuNPs, an opposite behavior is found: a loss compensation mechanism, based on a resonant energy transfer process from gain units to plasmonic nanoparticles, limits the increase of the absorption cross section with a consequent lowering of the photothermal efficiency. The presented quantitative analysis of a dispersion of AuNPs results as fundamental for biomedical applications as well as for integrated plasmonic devices based on loss compensation effects, where the impact of undesirable thermal effects cannot be ignored.

Biocompatibility and photo-induced antibacterial activity of lignin-stabilized noble metal nanoparticles

“…The first one involves the absorption of light by the MNP and the concomitant local release of heat from the particle that can destroy biomolecules (or melt the lipids in a cell membrane) in close proximity to the MNP surface. 51 The photochemical mechanism implicates the production of ROS by electron transfer processes from MNP to oxygen in the media. The later can be determined by a simple measurement of ROS generated during irradiation process.…”

Metallic Nanoparticle-Based Optical Cell Chip for Nondestructive Monitoring of Intra/Extracellular Signals

“…In addition, the fluorescence-based system has been pointedly improved by metallic nanomaterials, which provide recognition of the interaction between a target on the cell and signal transduction from biomolecular events (e.g., binding of antigen-antibody) to fluorescent signals. MNPs can be easily functionalized for biomolecular detection processes using their specific properties such as quenching and metal-enhanced fluorescence effects, making them excellent platforms for sensing at the cell level [39,[53][54][55][56].…”

“…In addition, fluorescent signals can also be quenched or enhanced due to the energy transfer between the MNPs and fluorophore [36][37][38]. Moreover, MNP's plasmonic effects can be tuned by selecting the optimal wavelength of the light source and exposure time to minimize a photothermal effect which can give a damage on the bio-analytes [39,40]. These great properties have led to the development of biosensors for in vitro cellular analysis on a cellular level and diagnosis of specific diseases at the molecular level.…”

Sunlight-Driven Photothermal Effect of Composite Eggshell Membrane Coated with Graphene Oxide and Gold Nanoparticles

“…Comprehensive theoretical modeling was developed to study the plasmonic heat production from a single layer of randomly distributed AuNPs and compared with the experimental results [10]. The influencing factors of the photothermal conversion of AuNPs solutions, including nanoparticle size, the exciting laser intensity, and the presence of guest dye molecules, were also investigated [11].…”