Laser-driven formation of chiral and achiral plasmonic nanostructures for biosensing applications Текст научной статьи по специальности «Нанотехнологии»

Laser-driven formation of chiral and achiral plasmonic nanostructures for biosensing applications

D.R. Dadadzhanov12*, N.S. Petrov2, A.V. Palekhova2, I.A. Gladskikh2, T.A. Vartanyan2, G. Markovich1

1- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University,

Tel Aviv 6997801, Israel

2- International Research and Education Centre for Physics of Nanostructures, ITMO University, 49 Kronverksky Pr., St. Petersburg 197101, Russian Federation

* daler.dadadzhanov@gmail.com

In this work we utilized pulsed and continuous wave laser to prepare achiral and chiral nanoparticles made of silver. The second harmonic of pulsed Nd:YAG laser was applied for formation of silver nanoparticles in water solution. A straightforward physical technique has been introduced to produce stable oligomers of silver nanoparticles. These nanoparticles are initially generated through pulsed laser ablation of a metal target submerged in a liquid. The formation of silver nanoparticle oligomers occurs in an aqueous solution after extended centrifugation at 18,000 g, followed by ultrasonication of the original colloidal solution containing spherical nanoparticles produced by laser ablation. The plasmon resonance in these oligomers shifts by 140 nm to the longer-wavelength region compared to the plasmon resonance of the spherical nanoparticles. Thanks to their capability to shift plasmon resonance into the long-wavelength spectral region without relying on conventional chemical synthesis methods, surfactant-free silver nanoparticle oligomers hold significant promise for diverse applications in biomedical imaging, targeted drug delivery, and photothermal therapy.

Another approach to utilizing laser radiation involved the application of continuous visible lasers (405 nm and 532 nm) on isotropic silver nanoparticles, which were produced by depositing metal vapors onto a dielectric substrate. The transformation from achiral silver nanostructures, consisting of nanoparticles with inhomogeneous sizes and shapes, to chiral structures using continuous wave laser with circularly polarized states was explored. We propose that chirality induction relies on disrupting the equilibrium between two "enantiomers" through laser heating of resonant and non-resonant silver nanoparticles, subsequently prompting reshaping.

This work was supported by the Russian Science Foundation (Project 22-72-10057).