Quantifying the photothermal conversion efficiency of plasmonic nanoparticles by means of terahertz radiation

Abstract

The accurate determination of the photothermal response of nanomaterials represents an essential aspect in many fields, such as nanomedicine. Specifically, photothermal cancer therapies rely on the precise knowledge of the light-to-heat transfer properties of plasmonic nanoparticles to achieve the desired temperature-induced effects in biological tissues. In this work, we present a novel method for the quantification of the photothermal effect exhibited by nanoparticles in aqueous dispersions. By combining the spatial and temporal thermal dynamics acquired at terahertz frequencies, the photothermal conversion efficiency associated with the geometry of the plasmonic nanoparticles can be retrieved in a noncontact and noninvasive manner. The proposed technique can be extended to the characterization of all those nanomaterials which feature a temperature-dependent variation of the refractive index in the terahertz regime.

Plasmonic Coupling in Silver Nanoparticle Aggregates and Their Polymer Composite Films for Near-Infrared Photothermal Biofilm Eradication

“…The spectra after the PDMS encasing exhibit some changes in their peak extinction due to film restructuring ( Figure S10 ); however, the PDMS-encased nanoparticle film retains the spatial homogeneity and NIR extinction of the bare plasmonic film on glass, while exhibiting a superior structural stability. The photothermal efficiency of the nanoparticle films was determined to be 50% according to the analysis described by Breitenborn et al 41 ( Figure S11 ), and the deposited mass was calculated to be 15.4 μg. The developed photothermal coatings exhibit high stability upon repeated treatments ( Figure S12 ).…”

Carbon Dot Therapeutic Platforms: Administration, Distribution, Metabolism, Excretion, Toxicity, and Therapeutic Potential

“…For example, temperatures above ≈40 °C can damage and destroy cancer cells with minimal damage to normal tissues. [74] Bao et al (2018) generated sulfur containing CDs via a solvothermal synthesis approach which not only targeted tumor tissues but also possessed a photothermal conversion efficiency of over 59% when irradiated with a laser at a wavelength of 655 nm at 1 W cm −2 . These biocompatible dots were able to reach 52.7 °C after 600 s of irradiation and completely destroyed tumor tissue within mice following 5 min of low powered laser irradiation.…”

Spatiotemporally Controlling the Release of Biological Effectors Enhances Their Effects on Cell Migration and Neurite Outgrowth

“…In addition, the photothermal conversion efficiency of ICG also plays an important role in determining the temperature rise under laser irradiation, which usually can be calculated based on the energy balance equation. [49,50] However, the PCM features a great latent heat of fusion with regard to melting or solidification in the context of solid-to-liquid phase transition. As such, PCM can absorb and release a large amount of heat within a relatively narrow range of temperature variation.…”