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Тимошенко, Виктор Юрьевич

Организационные подразделения

Организационная единица

Инженерно-физический институт биомедицины

Цель ИФИБ и стратегия развития – это подготовка высококвалифицированных кадров на базе передовых исследований и разработок новых перспективных методов и материалов в области инженерно-физической биомедицины. Занятие лидерских позиций в биомедицинских технологиях XXI века и внедрение их в образовательный процесс, что отвечает решению практикоориентированной задачи мирового уровня – диагностике и терапии на клеточном уровне социально-значимых заболеваний человека.

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Тимошенко

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Виктор Юрьевич

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Heating of aqueous suspensions of silicon nanoparticles by a 808-nm diode laser for application in local photohyperthermia
(2020) Oleshchenko, V. A.; Bezotosnyi, V. V.; Timoshenko, V. Y.; Тимошенко, Виктор Юрьевич
3D simulation of the distribution of thermal fields in aqueous suspensions of silicon nanoparticles upon irradiation by a high-power 808-nm laser diode operating in cw and quasi-cw repetitively pulsed regimes is performed. It is shown that irradiation by a repetitively pulsed laser with a peak power of 10 W and a pulse duration of 300 ms can form a region with a maximum temperature exceeding 42 degrees C, which is promising for application in cancer photohyperthermia for local heating of biotissues at a given depth.
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Optical Diagnostics of Free Charge Carriers in Silicon Nanowire Arrays
(2020) Rodichkina, S. P.; Nychyporuk, T.; Pavlikov, A. V.; Lysenko, V.; Timoshenko, V. Y.; Тимошенко, Виктор Юрьевич
The impact of free charge carriers in arrays of silicon nanowires (SiNWs) of p- and n-type conductivities on their optical properties is probed by means of the infrared spectroscopy in attenuated total reflectance mode (IR-ATR) and Raman scattering. SiNWs are fabricated by metal-assisted chemical etching of low-doped p-type crystalline silicon (c-Si) wafers followed by thermodiffusional doping with p- and n-type impurities. The free charge carrier concentration in SiNWs is determined from their ATR spectra fitted using a model of the anisotropic effective medium with free charge carriers. The obtained data on the free charge carrier concentrations in the range of 10(19)-10(20) cm(-3) are compared with the corresponding values obtained from the Raman spectra, which are analyzed by considering the Fano effect in SiNWs, and the results of both methods are used to evaluate the electrical properties of SiNWs. The proposed optical methods to probe the electrical properties of SiNWs are discussed in view of possible applications in nanoelectronics and thermoelectric devices.
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Interaction of SiFe Nanoparticles with Epithelial and Lymphoid Cells
(2020) Sharonova, N. V.; Svirshchevskaya, E. V.; Popov, A. A.; Karpov, N. V.; Tikhonovsky, G. V.; Zakharkiv, A. Y.; Timoshenko, V. Y.; Klimentov, S. M.; Oleinikov, V. A.; Попов, Антон Александрович; Тихоновский, Глеб Валерьевич; Захаркив, Анастасия Юрьевна; Тимошенко, Виктор Юрьевич; Климентов, Сергей Михайлович; Олейников, Владимир Александрович
Silicon and silicon-based nanoparticles (SiNP) attract scientific attention due to the biocompatibility and assimilation of silicon by body tissues. Iron-doped SiNP (SiFeNP) allow the use of ferromagnetic properties of iron for NP detection and the possibility of therapeutic application of SiFeNP. The purpose of this work was to analyze the interaction of SiFeNP with epithelial cells (EC) COLO357 and SW620 and human peripheral blood lymphocytes (PBL). SiFeNP were obtained by laser ablation and divided into the NP1 and NP2 fractions of 100 and 150 nm size, respectively. Cytotoxicity, apoptosis induction, reactive oxygen species (ROS) production, and lysosome metabolism were analyzed using in vitro methods. EC were found to efficiently incytosed both types of NPs, which resulted in the increase in the granularity of cells. NP did not cause apoptosis or EC necrosis, but accumulated in lysosomes, which led to a decrease in the membrane potential of lysosomes. In turn, a decrease in the level of EC metabolism led to a gradual (24 h) increase in ROS production by 10-15%. NP1 caused more ROS than NP2, and accumulated more in the EC, which may be the result of a difference in the particle size. SiFeNP did not interact with PBL. Thus, the total cytotoxicity of SiFeNP did not exceed 20%, which is associated with a decrease in lysosome metabolism and insignificant ROS production.
Только метаданные
Vibrational Analysis of Silicon Nanoparticles Using Simulation and Decomposition of Raman Spectra
(2020) Povarnitsyn, M. E.; Shcheblanov, N. S.; Ivanov, D. S.; Timoshenko, V. Y.; Klimentov, S. M.; Тимошенко, Виктор Юрьевич; Климентов, Сергей Михайлович
We report a classical molecular-dynamics simulation of models of silicon nanoparticles and bulk sili-con, in both the crystalline and the amorphous phase, to investigate their vibrational properties. By using a dynamical-matrix approach and a bond-polarizability model, together with a Raman-decomposition approach [Phys. Rev. B 100, 134309 (2019)], we present a comprehensive analysis of the vibrational spec-tra. In particular, the dependence of the high-frequency range of the Raman spectra on the nanoparticle size is studied. The results are in good agreement with Raman measurements on crystalline nanoparticles and explain the role of the nanoparticle surface, which is responsible for a shift in the Raman spectrum dependent on the particle size. In the low-frequency range, our Raman calculations reproduce well the Lamb-mode signatures, which obey the selection rules deduced by Duval [Phys. Rev. B 46, 5795 (1992)]. As a result of systematic Raman modeling, we confirm the scaling of the main signatures (ascribed to the Lamb modes with l = 0, 2) with respect to the nanoparticle size. By using the Raman-decomposition approach, we demonstrate that only a thin surface layer several angstroms in thickness contributes to the low-frequency Raman signature regardless of the nanoparticle size in the case of both the amorphous and the crystalline phase. Finally, we study the role of the coordination number of the atoms in the surface layer of a nanoparticle in order to explain the difference between the crystalline and amorphous vibrational spectra. The approach developed provides knowledge necessary for the correct interpretation of Raman spectra of nanoparticles, which opens up the possibility of quantitative control of surface-induced effects that may be relevant to various applications.
Только метаданные
Silicon Nanoparticles Prepared by Plasma-Assisted Ablative Synthesis: Physical Properties and Potential Biomedical Applications
(2019) Perepukhov, A. M.; Zvereva, E. A.; Koshelev, A. V.; Maximychev, A. V.; Kargina, Y. V.; Kharin, A. Y.; Zinovyev, S. V.; Alykova, A. F.; Pirogov, Y. A.; Timoshenko, V. Y.; Тимошенко, Виктор Юрьевич
© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Silicon (Si) nanoparticles (NPs) with small (10 −3 –10 −1 at%) content of iron oxide (Fe 2 O 3 ) are prepared by plasma-assisted ablative synthesis. Powders of the prepared Si-iron oxide (SIO) NPs are investigated by means of the transmission electron microscopy, Raman spectroscopy, electron paramagnetic resonance, and magnetic susceptibility measurements. Aqueous suspensions of the NPs are studied by using dynamic light scattering and nuclear magnetic resonance technique. The longitudinal and transverse relaxation times of protons in aqueous suspensions of the NPs are found to be dependent on the iron content. The stronger decrease of the proton relaxation is detected for the samples with higher iron content. Magnetic resonance imaging (MRI) experiments show that SIO NPs have properties of the MRI contrast agent and it is confirmed by in vivo experiments with cancer tumor. Aqueous suspensions of SIO NPs are explored as sensitizers of electromagnetic radio frequency hyperthermia and the highest heating rate is observed for the NPs with smaller hydrodynamic size (≈50 nm). The obtained results indicate possible ways for applications of SIO NPs in the MRI diagnostics and mild therapy of cancer.
Только метаданные
Bi-Modal Nonlinear Optical Contrast from Si Nanoparticles for Cancer Theranostics
(2019) Rogov, A.; Ryabchikov, Y. V.; Geloen, A.; Tishchenko, I.; Kharin, A. Y.; Lysenko, V.; Zavestovskaya, I. N.; Kabashin, A. V.; Timoshenko, V. Y.; Завестовская, Ирина Николаевна; Кабашин, Андрей Викторович; Тимошенко, Виктор Юрьевич
© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Presenting a safe alternative to conventional compound quantum dots and other functional nanostructures, nanosilicon can offer a series of breakthrough hyperthermia-based therapies under near-infrared, radiofrequency, ultrasound, etc., excitation, but the size range to sensitize these therapies is typically too large (>10 nm) to enable efficient imaging functionality based on photoluminescence properties of quantum-confined excitonic states. Here, it is shown that large Si nanoparticles (NPs) are capable of providing two-photon excited luminescence (TPEL) and second harmonic generation (SHG) responses, much exceeding that of smaller Si NPs, which promises their use as probes for bi-modal nonlinear optical bioimaging. It is finally demonstrated that the combination of TPEL and SHG channels makes possible efficient tracing of both separated Si NPs and their aggregations in different cell compartments, while the resolution of such an approach is enough to obtain 3D images. The obtained bi-modal contrast provides lacking imaging functionality for large Si NPs and promises the development of novel cancer theranostic modalities on their basis.
Только метаданные
Photo-induced cubic-to-hexagonal polytype transition in silicon nanowires
(2019) Rodichkina, S. P.; Belarouci, A.; Bezverkhyy, I.; Chassagnon, R.; Lysenko, V.; Timoshenko, V. Y.; Тимошенко, Виктор Юрьевич
© 2019 The Royal Society of Chemistry.Transformation of the crystalline lattice in silicon nanowires from cubic diamond (cub-Si) to hexagonal diamond (hex-Si) was observed under laser irradiation at intensities above 10 kW cm-2 (wavelength of 473 nm) by appearance of an additional peak in their Raman spectra in the range from 490 to 505 cm-1. Formation of the hex-Si phase in SiNWs is favoured by strong mechanical stresses caused by inhomogeneous photo-induced heating, which results in a singlet-doublet splitting of the Raman peaks for LO and TO phonons at about 517 and 510 cm-1, respectively. The estimated values of the photo-induced mechanical stresses and temperatures required for the polytype transformation in SiNWs correspond to those for bulk Si. The formation of the hex-Si phase in SiNWs is further illustrated by huge photoluminescence (PL) enhancement at laser intensities above 10 kW cm-2, which correlates with the appearance of the Raman peak at about 500 cm-1. The spectral position of the PL band at about 1.5 eV is close to the direct band gap transition in the stressed hex-Si.
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Acceleration of the Decay of Excitons in an Organometallic Perovskite Film on the Crystalline Silicon Surface
(2019) Sekerbayev, K. S.; Taurbayev, Y. T.; Ionin, A. A.; Saraeva, I. N.; Kudryashov, S. I.; Timoshenko, V. Y.; Тимошенко, Виктор Юрьевич
© 2019, Pleiades Publishing, Inc.It has been found that the optical properties and characteristics of exciton photoluminescence in thin organometallic perovskite layers, which are promising for application in high-efficiency solar cells, change when these layers are deposited on a crystalline silicon (c-Si) substrate. The observed shift of the photoluminescence band toward higher photon energies and a decrease in the lifetime of photoluminescence compared to layers deposited on a glass substrate with conducting metal oxide coating have been explained by the effect of an electric field that is formed in an organometallic perovskite/c-Si heterostructure and leads to the field ionization and the decay of excitons in the organometallic perovskite layer.
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Reflectance Modification in Nanostructured Silicon Layers with Gradient Porosity
(2019) Mussabek, G. K.; Yermukhamed, D.; Suleimenova, Z. A.; Assilbayeva, R. B.; Zavestovskaya, I. N.; Timoshenko, V. Y.; Завестовская, Ирина Николаевна; Тимошенко, Виктор Юрьевич
A significant change in effective reflectance spectra of nanostructured porous silicon layers grown with different times of metal-assisted chemical etching is detected. The low reflectances at the level of 5-10% measured in the spectral range of 200-400 nm are explained by strong elastic scattering of light in combination with absorption in silicon nanostructures, while a reflectance increase in the range of 500-1800 nm, which is visually detected as a "white" layer appearance is associated with Mie scattering in silicon nanostructures with gradient porosity under conditions of weak optical absorption. The results obtained are discussed from the viewpoint of potential applications of "black" and "white" nanocrystalline silicon in photonics and sensorics.
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Radiofrequency Heating of Nanoparticles for Biomedical Applications
(2021) Grigoriev, A. A.; Grigoryeva, M. S.; Kargina, Y. V.; Kharin, A. Y.; Zavestovskaya, I. N.; Kanavin, A. P.; Timoshenko, V. Y.; Григорьев, Андрей Андреевич; Григорьева, Мария Сергеевна; Завестовская, Ирина Николаевна; Канавин, Андрей Павлович; Тимошенко, Виктор Юрьевич
© 2021, Allerton Press, Inc.Abstract: The heat release during electromagnetic high-frequency (HF) heating of solid-state nanoparticle (NP) suspensions in an electrolyte with physiological solution conductivity is studied. It is shown that heating of a colloidal NP solution in an electrolyte should be calculated taken into account the contribution of an electric double layer formed near the NP surface, and the heating efficiency is controlled by the NP conductivity and the ratio of the frequency of radio-frequency radiation and the electrolyte conductivity. The optimal conductivity of silicon-based NPs for hyperthermia is determined as a function of the HF radiation frequency.