Morphology Dependence in Photothermal Heating of Gold Nanomaterials with Near-Infrared Laser

The selection of gold nanomaterials (GNMs) for potential use in photothermal therapeutic applications depends on a few parameters including their morphology, size, and surface functionalization. We report experimental and theoretical studies of the photothermal efficiency of GNMs of a few different morphologies, including gold nanoparticles (AuNPs) of the spherical shape, gold nanorods (GNRs), and gold nanourchins (GNUs), as well as spherical gold nanoparticle conjugates (AuNPC), where 20 nm AuNPs were functionalized with an IR 808 dyes. The photothermal conversion efficiencies (η) were obtained by using the experimental results from the heating of GNMs with an IR 808 nm laser. We demonstrate that the surface functionalization of spherical gold nanoparticles of 20 nm size increases their photothermal efficiency by a factor of 4 as compared to the same size spherical AuNPs.