title: Temperature determination of resonantly excited plasmonic branched gold nanoparticles by X-ray absorption spectroscopy.
abstract: The fields of bioscience and nanomedicine demand precise thermometry for nanoparticle heat characterization down to the nanoscale regime. Since current methods often use indirect and less accurate techniques to determine the nanoparticle temperature, there is a pressing need for a direct and reliable element-specific method. In-situ extended X-ray absorption fine structure (EXAFS) spectroscopy is used to determine the thermo-optical properties of plasmonic branched gold nanoparticles upon resonant laser illumination. With EXAFS, the direct determination of the nanoparticle temperature increase upon laser illumination is possible via the thermal influence on the gold lattice parameters. More specifically, using the change of the Debye-Waller term representing the lattice disorder, the temperature increase is selectively measured within the plasmonic branched nanoparticles upon resonant laser illumination. In addition, the signal intensity shows that the nanoparticle concentration in the beam more than doubles during laser illumination, thereby demonstrating that photothermal heating is a dynamic process. A comparable temperature increase is measured in the nanoparticle suspension using a thermocouple. This good correspondence between the temperature at the level of the nanoparticle and at the level of the suspension points to an efficient heat transfer between the nanoparticle and the surrounding medium, thus confirming the potential of branched gold nanoparticles for hyperthermia applications. This work demonstrates that X-ray absorption spectroscopy-based nanothermometry could be a valuable tool in the fast-growing number of applications of plasmonic nanoparticles, particularly in life sciences and medicine.
authors: IMEC, Bio-Nano Electronics, Functional Nanosystems, Kapeldreef 75, 3001 Leuven, Belgium; Department of Chemistry, Quantum Chemistry and Physical Chemistry, K.U. Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium. bieke.vandebroek@gmail.com.
authors: Bieke
authors: B
authors: Van de Broek
authors: Didier
authors: D
authors: Grandjean
authors: Jesse
authors: J
authors: Trekker
authors: Jian
authors: J
authors: Ye
authors: Kris
authors: K
authors: Verstreken
authors: Guido
authors: G
authors: Maes
authors: Gustaaf
authors: G
authors: Borghs
authors: Sergey
authors: S
authors: Nikitenko
authors: Liesbet
authors: L
authors: Lagae
authors: Carmen
authors: C
authors: Bartic
authors: Kristiaan
authors: K
authors: Temst
authors: Margriet J
authors: MJ
authors: Van Bael
mesh_terms: D006046:Gold / Q000737:chemistry / Q000528:radiation effects; D006358:Hot Temperature; D006801:Humans; D053685:Laser Therapy; D007834:Lasers; D053768:Metal Nanoparticles / Q000737:chemistry / Q000528:radiation effects / Q000648:ultrastructure; D050997:Nanomedicine; D036103:Nanotechnology; D020349:Surface Plasmon Resonance; D062125:Thermometry / Q000379:methods; D056928:X-Ray Absorption Spectroscopy / Q000379:methods
chemical_list: D006046:Gold