Quantitative Evaluation of Nanosecond Pulsed Laser-Induced Photomodification of Plasmonic Gold Nanoparticles
Andrew M Fales1, William C Vogt2, T Joshua Pfefer2
1Division of Biomedical Physics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, 10903 New Hampshire Ave, Building 62, Silver Spring, MD, 20993, USA. andrew.fales@fda.hhs.gov.
Abstract:
The rapid growth of gold nanoparticle applications in laser therapeutics and diagnostics has brought about the need for establishing innovative standardized test methods for evaluation of safety and performance of these technologies and related medical products. Furthermore, given the incomplete and inconsistent data on nanoparticle photomodification thresholds provided in the literature, further elucidation of processes that impact the safety and effectiveness of laser-nanoparticle combination products is warranted. Therefore, we present a proof-of-concept study on an analytical experimental test methodology including three approaches (transmission electron microscopy, dynamic light scattering, and spectrophotometry) for experimental evaluation of damage thresholds in nanosecond pulsed laser-irradiated gold nanospheres, and compared our results with a theoretical model and prior studies. This thorough evaluation of damage threshold was performed based on irradiation with a 532 nm nanosecond-pulsed laser over a range of nanoparticle diameters from 20 to 100 nm. Experimentally determined damage thresholds were compared to a theoretical heat transfer model of pulsed laser-irradiated nanoparticles and found to be in reasonably good agreement, although some significant discrepancies with prior experimental studies were found. This study and resultant dataset represent an important foundation for developing a standardized test methodology for determination of laser-induced nanoparticle damage thresholds.
