CC BY
4The 30th International Conference on Advanced Laser Technologies
ALT'23
B-I-l
One-shot laser-pulse modification of Au and Au@SiO2 nanoparticles
of various shapes and morphology
N. Khlebtsov1'2, V. Khanadeev1'3, A. Simonenko1'2' O. Grishin2, L. Dykman1
1-Institute of Biochemistry and Physiology of Plants and Microorganisms, Saratov Scientific Centre of the Russian Academy of Sciences (IBPPMRAS), 13 Prospect Entuziastov, Saratov 410049, Russia 2- Saratov State University, 83 Ulitsa Astrakhanskaya, Saratov 410012, Russia 3 -Saratov State University of Genetics, Biotechnology, and Engineering named after N. I. Vavilov
e-mail: khlebtsov@ibppm.ru
Gold and hybrid SiO2@Au / Au@SiO2 nanoparticles are widely used in laser biomedical applications as photothermal, sensoric, bioimaging, and therapeutic agents due to their favorable near-field and far-field optical properties based on localized plasmon resonance (PR). However, laser radiation can cause a change in the shape and size of plasmonic nanoparticles thus resulting in an unwanted reduction of their photothermal and photodynamic efficiency due to a drastic alteration of optical properties. Most previously reported experiments were carried out with bulk colloids where different particles were irradiated by different numbers of laser pulses thus making it difficult accurately evaluate the laser power photomodification (PM) threshold. Here, we examine the one-shot nanosecond laser-pulse PM of bare and silica-coated gold nanoparticles moving in a capillary flow [1]. Four types of gold nanoparticles, including nanostars, nanoantennas, nanorods, and SiO2@Au nanoshells were fabricated for PM experiments. To evaluate the changes in the particle morphology under laser irradiation, we combine measurements of extinction spectra with electron microscopy. A quantitative spectral approach is developed to characterize the laser power PM threshold in terms of normalized extinction parameters: PMfactor = [q(0) - q(F)]/[q(0) - q(Fmax)], q(F)=A(F, PR)/A(F, 550), where A(F, PR) is the extinction of particles at PR wavelength after PM treatment with the fluence value F; A(F, 550) is the extinction value at the wavelength of the short-wavelength maximum in the region of 500-600 nm (if it exists), or is the extinction value at the wavelength of 550 nm, if there is no maximum in this region. The experimentally determined PM threshold increases in series: nanorods, nanoantennas, nanoshells, and nanostars. An important observation is that even a thin silica shell significantly increases the photostability of gold nanorods (Fig. 1). The developed methods and reported findings can be useful for the optimal design of plasmonic particles and laser irradiation parameters in various biomedical applications of functionalized hybrid nanostructures.
10° 101 102 103 104 101 102 103 104 Fluence, mJ/cm2 Fluence (mJ/cm2)
Fig. 1. Scheme of pulsed laser irradiation of nanoparticles moving in a capillary (a) and photomodification factor as a function of fluence for bare (b) and silica-coated (c) gold nanorods. A 30-nm silica coating increases the 90%-PM fluence threshold from 200 to 2000 mJ/cm2.
This work was supported by the Russian Scientific Foundation (project No. 19-14-00077).
[1] Khanadeev V., Simonenko A., Grishin O., Khlebtsov N. One-shot laser-pulse modification of bare and silica-coated gold nanoparticles of various morphologies. Nanomaterials, vol. 13, 1312 (2023).
