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Gongalsky MB, Kargina JV, Cruz JF, Sánchez-Royo JF, Chirvony VS, Osminkina LA, Sailor MJ. Formation of Si/SiO 2 Luminescent Quantum Dots From Mesoporous Silicon by Sodium Tetraborate/Citric Acid Oxidation Treatment. Front Chem 2019; 7:165. [PMID: 30984738 PMCID: PMC6450366 DOI: 10.3389/fchem.2019.00165] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 03/04/2019] [Indexed: 11/13/2022] Open
Abstract
We propose a rapid, one-pot method to generate photoluminescent (PL) mesoporous silicon nanoparticles (PSiNPs). Typically, mesoporous silicon (meso-PSi) films, obtained by electrochemical etching of monocrystalline silicon substrates, do not display strong PL because the silicon nanocrystals (nc-Si) in the skeleton are generally too large to display quantum confinement effects. Here we describe an improved approach to form photoluminescent PSiNPs from meso-PSi by partial oxidation in aqueous sodium borate (borax) solutions. The borax solution acts to simultaneously oxidize the nc-Si surface and to partially dissolve the oxide product. This results in reduction of the size of the nc-Si core into the quantum confinement regime, and formation of an insulating silicon dioxide (SiO2) shell. The shell serves to passivate the surface of the silicon nanocrystals more effectively localizing excitons and increasing PL intensity. We show that the oxidation/dissolution process can be terminated by addition of excess citric acid, which changes the pH of the solution from alkaline to acidic. The process is monitored in situ by measurement of the steady-state PL spectrum from the PSiNPs. The measured PL intensity increases by 1.5- to 2-fold upon addition of citric acid, which we attribute to passivation of non-radiative recombination centers in the oxide shell. The measured PL quantum yield of the final product is up to 20%, the PL activation procedure takes <20 min, and the resulting material remains stable in aqueous dispersion for at least 1 day. The proposed phenomenological model explaining the process takes into account both pH changes in the solution and the potential increase in solubility of silicic acid due to interaction with sodium cations.
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Affiliation(s)
- Maxim B Gongalsky
- Faculty of Physics, Lomonosov Moscow State University, Moscow, Russia.,Department of Chemistry and Biochemistry, University of California, San Diego, San Diego, CA, United States
| | - Julia V Kargina
- Faculty of Physics, Lomonosov Moscow State University, Moscow, Russia
| | - Jose F Cruz
- Department of Chemistry and Biochemistry, University of California, San Diego, San Diego, CA, United States
| | | | | | - Liubov A Osminkina
- Faculty of Physics, Lomonosov Moscow State University, Moscow, Russia.,Institute for Biological Instrumentation of Russian Academy of Sciences, Moscow, Russia
| | - Michael J Sailor
- Department of Chemistry and Biochemistry, University of California, San Diego, San Diego, CA, United States
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Sviridov AP, Osminkina LA, Kharin AY, Gongalsky MB, Kargina JV, Kudryavtsev AA, Bezsudnova YI, Perova TS, Geloen A, Lysenko V, Timoshenko VY. Cytotoxicity control of silicon nanoparticles by biopolymer coating and ultrasound irradiation for cancer theranostic applications. Nanotechnology 2017; 28:105102. [PMID: 28177935 DOI: 10.1088/1361-6528/aa5b7c] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Silicon nanoparticles (SiNPs) prepared by mechanical grinding of luminescent porous silicon were coated with a biopolymer (dextran) and investigated as a potential theranostic agent for bioimaging and sonodynamic therapy. Transmission electron microscopy, photoluminescence and Raman scattering measurements of dextran-coated SiNPs gave evidence of their enhanced stability in water. In vitro experiments confirmed the lower cytotoxicity of the dextran-coated NPs in comparison with uncoated ones, especially for high concentrations of about 2 mg ml-1. Efficient uptake of the NPs by cancer cells was found using bioimaging in the optical transmittance and photoluminescence modes. Treatment of the cells with uptaken SiNPs by therapeutic ultrasound for 5-20 min resulted in a strong decrease in the number of living cells, while the total number of cells remained nearly unchanged. The obtained data indicate a 'mild' effect of the combined action of ultrasonic irradiation and SiNPs on cancer cells. The observed results reveal new opportunities for controlling the photoluminescent and sonosensitizing properties of silicon-based NPs for applications in the diagnostics and mild therapy of cancer.
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Affiliation(s)
- A P Sviridov
- Lomonosov Moscow State University, Department of Physics, 119991 Moscow, Russia
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Tamarov KP, Osminkina LA, Zinovyev SV, Maximova KA, Kargina JV, Gongalsky MB, Ryabchikov Y, Al-Kattan A, Sviridov AP, Sentis M, Ivanov AV, Nikiforov VN, Kabashin AV, Timoshenko VY. Radio frequency radiation-induced hyperthermia using Si nanoparticle-based sensitizers for mild cancer therapy. Sci Rep 2014; 4:7034. [PMID: 25391603 PMCID: PMC5382688 DOI: 10.1038/srep07034] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 10/24/2014] [Indexed: 11/16/2022] Open
Abstract
Offering mild, non-invasive and deep cancer therapy modality, radio frequency (RF) radiation-induced hyperthermia lacks for efficient biodegradable RF sensitizers to selectively target cancer cells and thus avoid side effects. Here, we assess crystalline silicon (Si) based nanomaterials as sensitizers for the RF-induced therapy. Using nanoparticles produced by mechanical grinding of porous silicon and ultraclean laser-ablative synthesis, we report efficient RF-induced heating of aqueous suspensions of the nanoparticles to temperatures above 45-50 °C under relatively low nanoparticle concentrations (<1 mg/mL) and RF radiation intensities (1-5 W/cm(2)). For both types of nanoparticles the heating rate was linearly dependent on nanoparticle concentration, while laser-ablated nanoparticles demonstrated a remarkably higher heating rate than porous silicon-based ones for the whole range of the used concentrations from 0.01 to 0.4 mg/mL. The observed effect is explained by the Joule heating due to the generation of electrical currents at the nanoparticle/water interface. Profiting from the nanoparticle-based hyperthermia, we demonstrate an efficient treatment of Lewis lung carcinoma in vivo. Combined with the possibility of involvement of parallel imaging and treatment channels based on unique optical properties of Si-based nanomaterials, the proposed method promises a new landmark in the development of new modalities for mild cancer therapy.
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Affiliation(s)
| | - Liubov A. Osminkina
- Lomonosov Moscow State University, Department of Physics, 119991 Moscow, Russia
| | | | - Ksenia A. Maximova
- Aix Marseille University, CNRS, LP3 UMR 7341, Campus de Luminy - Case 917, 13288, Marseille Cedex 9, France
| | - Julia V. Kargina
- Lomonosov Moscow State University, Department of Physics, 119991 Moscow, Russia
| | - Maxim B. Gongalsky
- Lomonosov Moscow State University, Department of Physics, 119991 Moscow, Russia
| | - Yury Ryabchikov
- Aix Marseille University, CNRS, LP3 UMR 7341, Campus de Luminy - Case 917, 13288, Marseille Cedex 9, France
| | - Ahmed Al-Kattan
- Aix Marseille University, CNRS, LP3 UMR 7341, Campus de Luminy - Case 917, 13288, Marseille Cedex 9, France
| | - Andrey P. Sviridov
- Lomonosov Moscow State University, Department of Physics, 119991 Moscow, Russia
| | - Marc Sentis
- Aix Marseille University, CNRS, LP3 UMR 7341, Campus de Luminy - Case 917, 13288, Marseille Cedex 9, France
| | | | | | - Andrei V. Kabashin
- Aix Marseille University, CNRS, LP3 UMR 7341, Campus de Luminy - Case 917, 13288, Marseille Cedex 9, France
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