CC BY
17B-I-2
Nanoparticles fabricated by laser ablation and fragmentation of nano- and microstructured silicon: perspectives in biophotonics applications
S.V. Zabotnov1, L.A. Golovan1, D.A. Kurakina2, A.V. Khilov21, E.A. Sergeeva21, D.V. Shuleiko1, O.I. Sokolovskaya1, V.Yu. Nesterov1, D. E. Presnov1, P.K. Kashkarov1, P.D. Agrba3,
M.Yu. Kirillin2
1-Lomonosov Moscow State University, Faculty of Physics, 1/2 Leninskie Gory, Moscow, 119991, Russia 2- Institute of Applied Physics RAS, 46 Uljanov street, Nizhny Novgorod, 603950, Russia 3- Lobachevsky State University of Nizhny Novgorod, 23 Gagarin avenue, Nizhny Novgorod, 603950,
Russia
Email: zabotnov@physics.msu.ru
Pulsed laser ablation in liquids (PLAL) is a convenient technique to fabricate nanoparticles with desirable size, physical and chemical properties [1,2]. Silicon nanoparticles (Si-NPs) produced employing this approach are promising in biophotonics [3-5] due to their biocompatibility and biodegradability. However, high-yield production of Si-NPs is quite time-consuming and requires employment of a high-power laser with significant pulse repetition rate. To enhance the efficiency of Si-NPs fabrication, we suggest using preliminary nano- or microstructured silicon instead of traditionally used crystalline silicon targets.
In our work we employed porous silicon films, silicon nanowires arrays and mechanically grinded silicon microparticles as targets for picosecond (1064 nm, 34 ps, 10Hz) and femtosecond (1250 nm, 160 fs, 10Hz) PLAL. Measurements of the ablation thresholds for the porous silicon and silicon nanowires targets in water and ethanol revealed that the thresholds to be several times smaller as compared to those for crystalline silicon and high-yield Si-NPs output is provided. Similar behavior was revealed for laser fragmentation of the silicon microparticles in these liquids.
Scanning electron microscopy and dynamic light scattering studies demonstrated that the mean Si-NPs sizes are in the range of 24-340 nm depending on the used target, buffer liquid, laser pulse duration and irradiation time. Raman spectroscopy data analysis revealed almost perfect crystallinity of the formed Si-NPs in the cases of silicon nanowires PLAL and laser fragmentation of the silicon microparticles.
The studied Si-NPs emit fluorescence in the range of 600-900 nm most likely caused by internal defects [4]. Fluorescence in this range indicates the prospects of the nanoparticles as fluorescence markers in optical bioimaging. Spectrophotometry measurements of the Si-NPs suspensions revealed their effective scattering in the spectral range of 400-1000 nm confirmed by Mie theory estimations. Optical coherence tomography imaging of the suspensions drops administered on agar gel surfaces indicated high efficiency of the Si-NPs as contrast agents providing the contrast up to 30 dB. Heating of tumor tissue with embedded nanoparticles using a laser beam was numerically modelled using real optical properties of nanoparticles suspensions in order to analyze Si-NPs efficiency for tumor hyperthermia [5]. The simulations indicate that embedding Si-NPs into a tumor results in increase of the heating maximum for up to 4°C in comparison with the same heating the tumor without nanoparticles.
Comparative analysis of the obtained results allowed to conclude on high potential of the Si-NPs fabricated via PLAL either in fluorescence and scattering bioimaging or in photohyperthermia.
This work was supported by the Russian Science Foundation (project № 19-12-00192).
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[3] A. Al-Kattan, Yu.V. Ryabchikov, T. Baati, et al., J. Mater. Chem. B, 4, 7852-7858 (2016).
[4] S.V. Zabotnov, A.V. Skobelkina, E.A. Serggeva, et al., Sensors, 20, 4874 (2020).
[5] O.I. Sokolovskaya, S.V. Zabotnov, L.A. Golovan, et al., Quantum Electron., 51(1), 64-72 (2021).
