Optical manipulation of metallic nanoparticles has numerous applications including nano-architectural control, enhancement of spectroscopic signals or photothermal treatment. Due to their large absorption cross sections, metallic nanoparticles, made of gold or platinum, generate significant heat upon irradiation and together with their large scattering cross sections, they can be challenging to optically trap and control. We demonstrate that strongly absorbing individual platinum nanoparticles can be optically trapped in three dimensions using a single focused continuous wave near infrared laser beam. Moreover, via direct measurements and finite element modeling, we show that platinum nanparticles have extraordinary thermoplasmonic properties and a single NIR irradiated platinum nanparticle with a diameter of 70 nm can reach surface temperature increases as high as 700°C in repeated heating cycles, thus demonstrating an exceptional thermal stability. Also, in comparison to the larger NIR resonant gold nanoshells, currently used for photothermal therapy, we show that the platinum nanparticles exhibit similar photothermal heating capacity and similar low toxicity. However, as the platinum nanoparticles exhibit better thermal stability than the gold nanoshells, they are quite promising for bioengineering and biomedical applications.

Date Published: 1 March 2019
PDF: 10 pages
Proc. SPIE 10935, Complex Light and Optical Forces XIII, 109351A (1 March 2019); doi: 10.1117/12.2513752

Published in SPIE Proceedings Vol. 10935:
Complex Light and Optical Forces XIII
Jesper Glückstad; David L. Andrews; Enrique J. Galvez, Editor(s)