Hybrid Orthorhombic Carbon Flakes Intercalated with Bimetallic Au-Ag Nanoclusters: Influence of Synthesis Parameters on Optical Properties

Until recently, planar carbonaceous structures such as graphene did not show any birefringence under normal incidence. In contrast, a recently reported novel orthorhombic carbonaceous structure with metal nanoparticle inclusions does show intrinsic birefringence, outperforming other natural orthorhombic crystalline materials. These flake-like structures self-assemble during a laser-induced growth process. In this article, we explore the potential of this novel material and the design freedom during production. We study in particular the dependence of the optical and geometrical properties of these hybrid carbon-metal flakes on the fabrication parameters. The influence of the laser irradiation time, concentration of the supramolecular complex in the solution, and an external electric field applied during the growth process are investigated. In all cases, the self-assembled metamaterial exhibits a strong linear birefringence in the visible spectral range, while the wavelength-dependent attenuation was found to hinge on the concentration of the supramolecular complex in the solution. By varying the fabrication parameters one can steer the shape and size of the flakes. This study provides a route towards fabrication of novel hybrid carbon-metal flakes with tailored optical and geometrical properties

Direct laser writing of μ-chips based on hybrid C–Au–Ag nanoparticles for express analysis of hazardous and biological substances

Micro-chips based on organic–inorganic hybrid nanoparticles (NPs) composed of nanoalloys of gold (Au) and silver (Ag) embedded in an amorphous carbonaceous matrix (C–Au–Ag NPs) were prepared directly on a substrate by the laser- induced deposition (for short: LID) method. The C–Au–Ag NPs show a unique plasmon resonance which enhances Raman scattering of analytes, making the μ-chips suitable to detect ultra-low-volumes (10−12 liter) and concentrations (10−9 M) of bio-agents and a hazardous compound. These micro-chips constitute a novel, flexible solid-state device that can be used for applications in point-of-care diagnostics, consumer electronics, homeland security and environmental monitoring

Photosensitive poly-l-lysine/heparin interpolyelectrolyte complexes for delivery of genetic drugs

Photo-triggered release of biopharmaceutical drugs inside the cells is a challenging direction of modern science, which requires obtaining new polymeric systems. The interpolyelectrolyte complexes (IPECs) of poly-l-lysine with heparin capable of encapsulation of genetic constructions-such as model oligonucleotide, siRNA, and pDNA-were obtained. Poly-l-lysine to heparin ratios were optimized to provide the appropriate release kinetics of genetic material from the polyplex. In order to impart the obtained IPEC with photosensitive properties, the linker was synthesized as based on 4-brommethyl-3-nitrobenzoic acid. The conditions and kinetics of photosensitive linker destruction were carefully studied. The colloid particles of IPEC were modified with Cy3 probe and their cellular internalization was investigated by flow cytometry method. The efficacy of photosensitive IPECs as siRNA and pDNA delivery system was evaluated. © 2020 by the authors

Изучение гемосовместимости магнитных наночастиц магнетита и композитных частиц магнетита-кремнезема in vitro

The goal of the present research is to study the hemocompatibility of magnetic nanoparticles (MNPs)  in model systems in vitro.Materials and methods. Magnetite nanoparticles and magnetite colloidal solutions were used in 0.9% NaCl in concentrations 0.2, 2.0 and 20.0 mg/ml. The study was performed with heparinized human whole blood, 1 ml of which was mixed with 1 of ml nanoparticles/physiological solution. Measurements were made directly after mixing, and then 1, 2.5 and 5 hours later. The amount of reactive oxygen species (ROS) was measured with luminol-dependent chemiluminiscence (CL). An erythrocyte aggregation index was calculated. For the assessment of hemolytic properties, a hemolysis coefficient was calculated based on optical density of the plasma. The nanoparticless surface protein layer investigation was performed with IR-Fourier spectroscopy.Results. Nanoparticles decline CL in timeand concentration-dependent manner. Erythrocyte aggregation stability grows, but concentration and/or application time increment leads to significant hemolysis. IR-Fourier spectroscopy data shows albumin as main component of protein crown, whose conformation changes in time.Given data proves safety of studied MNPs in relation to examined parameters in low (0.2 and 2.0 mg/ml) concentrations up to 2.5 hours interaction. This allows us to treat these MNPs as a promising agents for further use in medical practice after completing examinations related to other homeostasis indicators.Целью данного исследования явилось изучение гемосовместимости магнитных наночастиц (МНЧ) в модельных системах in vitro.Материалы и методы. В работе использованы коллоидные растворы наночастиц магнетита (МНЧ1) и композитных частиц магнетита-кремнезема (МНЧ2) в 0,9%-м растворе NaCl в концентрациях 0,2; 2,0 и 20,0 мг/мл. Исследование проводили на гепаринизированной цельной крови человека, для чего  к 1 мл крови добавляли 1 мл раствора наночастиц или физиологического раствора (контроль). Измерения проводили непосредственно после приготовления смеси через 1; 2,5 и 5 ч. Количество активных форм кислорода (АФК) детектировали с помощью метода люминолзависимой хемилюминесценции (ХЛ), вычисляли индекс агрегации эритроцитов, для оценки гемолитических свойств рассчитывали коэффициент гемолиза на основе показателей оптической плотности плазмы, исследование белкового слоя на поверхности наночастиц производили при помощи ИК-Фурье спектроскопии.Результаты. Установлено, что наночастицы обоих типов в концентрации 0,2 и 20,0 мг/мл усиливают ХЛ непосредственно после введения и подавляют ее в ходе инкубации, при этом эффект усиливается с увеличением концентрации и времени воздействия. Также отмечено увеличение агрегационной устойчивости эритроцитов, однако с повышением дозы и времени воздействия наблюдался значительный гемолиз. ИК-Фурье спектроскопия показала оседание альбумина на поверхности МНЧ, который меняет свою конформацию с течением времени.Таким образом, полученные данные свидетельствуют о безопасности данных МНЧ по исследованным параметрам в низких концентрациях (0,2 и 2,0 мг/мл) при взаимодействии до 2,5 ч. Это позволяет рассматривать данные агенты как перспективные средства для дальнейшего использования в медицинской практике после завершения исследований в отношении других показателей гомеостаза

Spatially-controlled laser-induced decoration of 2D and 3D substrates with plasmonic nanoparticles

We demonstrate a new approach which can be used for targeted imparting of plasmonic properties for a wide range of different substrates (transparent and non-transparent) which may have any 2D or 3D topological structure created independently in a prior step with some other technology

Novel 2D carbon allotrope intercalated with Au-Ag nanoclusters: from laser design to functionality

Hybrid metal/carbon flat micrometer sized crystals were created with a one-step laser-induced deposition process representing a novel 2D carbon allotrope with a hydrogenated sp2 structure and intercalated with heterometallic Au-Ag nanoclusters of 3nm diameter

Photoluminescence and Energy Transfer in Double- and Triple-Lanthanide-Doped YVO4 Nanoparticles

Optical materials doped with several lanthanides are unique in their properties and are widely used in various fields of science and technology. The study of these systems provides solutions for noncontact thermometry, bioimaging, sensing technology, and others. In this paper, we report on the demonstration of YVO4 nanoparticles doped with one, two, and three different rare earth ions (Tm3+, Er3+, and Nd3+). We discuss the morphology, structural properties, and luminescence behavior of particles. Luminescence decay kinetics reveal the energy transfer efficiency (up to 78%) for different ions under the selective excitation of individual ions. Thus, we found that the energy transition from Tm3+ is more favorable than from Er3+ while we did not observe any significant energy rearrangement in the samples under the excitation of Nd3+. The observed strong variation of REI lifetimes makes the suggested nanoparticles promising for luminescent labeling, anticounterfeiting, development of data storage systems, etc

Investigating the Optical Properties of a Laser Induced 3D Self‐Assembled Carbon–Metal Hybrid Structure

Carbon‐based and carbon–metal hybrid materials hold great potential for applications in optics and electronics. Here, a novel material made of carbon and gold–silver nanoparticles is discussed, fabricated using a laser‐induced self‐assembly process. This self‐assembled metamaterial manifests itself in the form of cuboids with lateral dimensions on the order of several micrometers and a height of tens to hundreds of nanometers. The carbon atoms are arranged following an orthorhombic unit cell, with alloy nanoparticles intercalated in the crystalline carbon matrix. The optical properties of this metamaterial are analyzed experimentally using a microscopic Müller matrix measurement approach and reveal a high linear birefringence across the visible spectral range. Theoretical modeling based on local‐field theory applied to the carbon matrix links the birefringence to the orthorhombic unit cell, while finite‐difference time‐domain simulations of the metamaterial relates the observed optical response to the distribution of the alloy nanoparticles and the optical density of the carbon matrix

Hemocompatibility of magnetic magnethite nanoparticles and magnetite-silica composites in vitro

The goal of the present research is to study the hemocompatibility of magnetic nanoparticles (MNPs)  in model systems in vitro.Materials and methods. Magnetite nanoparticles and magnetite colloidal solutions were used in 0.9% NaCl in concentrations 0.2, 2.0 and 20.0 mg/ml. The study was performed with heparinized human whole blood, 1 ml of which was mixed with 1 of ml nanoparticles/physiological solution. Measurements were made directly after mixing, and then 1, 2.5 and 5 hours later. The amount of reactive oxygen species (ROS) was measured with luminol-dependent chemiluminiscence (CL). An erythrocyte aggregation index was calculated. For the assessment of hemolytic properties, a hemolysis coefficient was calculated based on optical density of the plasma. The nanoparticless surface protein layer investigation was performed with IR-Fourier spectroscopy.Results. Nanoparticles decline CL in timeand concentration-dependent manner. Erythrocyte aggregation stability grows, but concentration and/or application time increment leads to significant hemolysis. IR-Fourier spectroscopy data shows albumin as main component of protein crown, whose conformation changes in time.Given data proves safety of studied MNPs in relation to examined parameters in low (0.2 and 2.0 mg/ml) concentrations up to 2.5 hours interaction. This allows us to treat these MNPs as a promising agents for further use in medical practice after completing examinations related to other homeostasis indicators