Search

The development of various nanomaterials production technologies has led to the possibility of producing nanoparticles (NPs) and nanostructures, which can find a wide range of applications, from the fabrication of microelectronic devices to the improvement of material properties and the treatment of cancer. The unique characteristics of nanoparticles are primarily due to their small size, which makes size control important in their preparation. Modification of nanoparticles by laser irradiation and obtaining desired nanoparticle properties is a promising approach because of its ease of implementation. The purpose of this review is to analyze the works devoted to the study of laser-induced heating and melting of nanoparticles, to collect information and evaluate the results of using this method for functionalization and modification of metallic nanoparticles, and to discuss promising directions for the use of this technique. [ABSTRACT FROM AUTHOR]

Introduction: The process of forming selenium nanoparticles with various shapes and structures through laser ablation and fragmentation in various solvents has been explored. Methods: Laser ablation and laser fragmentation techniques were employed using nanosecond Nd:YAG second harmonic laser irradiation in 9 different working fluids, including water. The characteristics of the resulting nanoparticles were assessed using transmission electron microscopy (TEM), dynamic light scattering (DLS), spectroscopy, and X-ray diffraction (XRD) methods. Results: Laser ablation and subsequent laser fragmentation of some organic solvents, such as ethanol, propanol-2, isobutanol, polyethylene glycol, and diethanolamine, have been found to produce trigonal selenium in the form of elongated nanorods approximately 1 μm long and 200 nm thick, with a well-defined crystal structure. In contrast, the use of deionized water, acetone, glycerol, and benzene as solvents results in the formation of spherical amorphous nanoparticles approximately 100 nm in diameter. Discussion: The polarity of the solvent molecules has been shown to influence the growth of crystalline selenium nanorods in solution during laser ablation and laser fragmentation. Generally, polar solvents hinder the growth of crystalline nanorods, due to interactions between selenium and solvent molecules. Nonpolar solvents, on the other hand, allow for laser fragmentation to reduce particle size and initiate the epitaxial growth of elongated, crystalline selenium nanorods. [ABSTRACT FROM AUTHOR]

In this paper, the effect of Nd:YAG laser radiation on the properties of the BSA protein is investigated. A solution with a protein concentration of 5 mg/ml was irradiated for 30 minutes. After a 5-minute and 30-minute exposure, absorption spectra were taken, the particle size in the solution was determined by dynamic light scattering (DLS), the refractive index was determined, and fluorescent maps were taken. Raman spectroscopy of proteins was also performed. The results showed that after irradiation, the absorption of the protein solution decreases in the spectral range corresponding to amino acid residues. In DLS experiments, it was shown that the peak corresponding to protein molecules decreases, and the peaks corresponding to large aggregates (>100 nm) grow. Raman spectroscopy has shown that there is a decrease in intensity at a wavelength of 1570 cm-1. There were no significant changes in the refractive indices and the shape of the fluorescent maps. The data suggest that partial denaturation of proteins took place.

Introduction: The process of laser-induced breakdown of amorphous and crystalline selenium nanoparticles (Se NPs) of various shapes during nanosecond laser fragmentation of aqueous colloidal solutions of nanoparticles with different concentrations has been studied. Methods: The methods of studying the characteristics of plasma and acoustic oscillations induced by optical breakdown are applied. The methods of assessing the concentration of hydrogen peroxide and hydroxyl radicals, the amount of long-lived reactive species of protein and 8-oxoguanine are applied. Results: It has been established that in the process of laser fragmentation of selenium nanoparticles at a wavelength of 532 nm, corresponding to the maximum absorption of selenium, the highest probability of breakdown, the number of plasma flashes, their luminosity and the amplitude of acoustic signals are achieved at concentrations of the order of 109 NPs/mL. It has been shown that the use of selenium nanoparticles of various shapes and structures leads to a change in the photoacoustic signal during laser-induced breakdown. When crystalline selenium nanoparticles are irradiated, the intensity of the photoacoustic response during breakdown turns out to be greater (1.5 times for flash luminosity and 3 times for acoustics) than when amorphous particles are irradiated at the same concentration. It has been shown that selenium nanoparticles exhibit significant antioxidant properties. Selenium nanoparticles effectively prevent the formation of reactive oxygen species (ROS) during water radiolysis, eliminate radiation-induced long-lived reactive species of protein, and reduce the radiation-chemical yield of a key marker of oxidative DNA damage 8-oxoguanine. Discussion: In general, the intensity of processes occurring during laser fragmentation of amorphous and crystalline selenium nanoparticles differs significantly. The antioxidant properties are more pronounced in amorphous selenium nanoparticles compared to crystalline selenium nanoparticles. [ABSTRACT FROM AUTHOR]

Due to widespread selenium deficiency in food the aim of this study was to evaluate the effectiveness of a new Se(II)-containing organic chemical compound 2-iminoselenazolidin-4-ones (ISeA) in the form of a nanoscale associate (1–5 nm) solution for Swiss chard and komatsuna plants biofortification. Application of the chosen substance as a foliar treatment (2 mg·L−1) and as an additive to a hydroponic nutrient solution (10 mg·L−1) was performed. Both cultures had a high level of Se absorption, distribution and accumulation in leaves two or more times greater than in petioles. Se content in chard petioles (15 mg·L−1) when applying ISeA as a component of the nutrient solution exceeded the accumulation of Se during foliar treatment (9.6 mg·L−1) and the same trend in the komatsuna leaves was observed. When applying ISeA to the nutrient solution, an increase in komatsuna and chard biomass was seen at 36 and 68% and for leaf treatment by 21 and 45%, respectively. For komatsuna and chard an increase in the ratio of dry to fresh weight was also observed to be 27 and 26%, and for foliar treatment—0 and 16 % , respectively. Treatments led to increase in chard plants height (7–17%), enlargement of leaves (19–42%), a rise in photosynthetic pigments (20–60%) and anthocyanin (2.9 and 2.2 times) concentration, and for komatsuna—the multiplication of leaves number ( 28 % ) and their surface area (27–29%) as well as a rise in the concentration of anthocyanin (1.0 and 1.6 times) with foliar treatment and nutrient solution enrichment. [ABSTRACT FROM AUTHOR]

The anti-cancer effects of selenium sources are well known. Among other things, selenium has been shown to have a pleiotropic effect, causing cancer cell death without affecting the healthy cell's viability, or, in the case of brain cells, has a cytoprotective effect. This feature of selenium determined its use in medicine and its use as part of dietary supplements. In recent years, selenium in the form of nanoparticles has received increased attention. Selenium nanoparticles also have anti-cancer effects, and their use appears to be more effective at significantly lower doses compared to other sources of selenium. The shape and size of nanoparticles largely affect the efficiency of nanoselenium application. We obtained two different types of selenium nanoparticles via the laser ablation technique—spherical selenium nanoparticles (SeNPs) about 100 nm in diameter and grown selenium nanorods (SeNrs) about 1 μm long and about 100 nm thick. We compared the anti-cancer efficacy of these two types of selenium nanoparticles using inhibitory analysis, PCR analysis and fluorescence microscopy. It turned out that both types of nanoparticles with high efficiency dose-dependently activate apoptosis in the human glioblastoma cell line A-172, as the most aggressive type of brain tumor. Apoptosis induction was determined not only by the concentration of nanoparticles, but also by the time. It was shown that SeNrs induce the process of apoptosis in glioblastoma cells more efficiently during 24 h of exposure and their effect is enhanced after 48 h without activation of necrosis, whereas the use of spherical SeNPs after 48 h of exposure can cause necrosis in some glioblastoma cells. It has been shown that Ca2+ signals of glioblastoma cells are significantly different for SeNPs and SeNrs. SeNPs cause a dose-dependent transient increase in the number of Ca2+ ions in the cell cytosol ([Ca2+]i), while SeNrs cause a slow rise in [Ca2+]i reaching a new stationary level, which may determine the cytotoxic effects of nanoparticles. It turned out that SeNPs and SeNrs cause depletion of the Ca2+ depot of the endoplasmic reticulum and ER-stress, which correlates with increased expression of genes encoding proapoptotic proteins. In our study, it was found that SeNPs do not activate the Ca2+ signaling system of healthy L-929 mouse fibroblast cells, while SeNrs activate a moderate slow growth in [Ca2+]i. That fact could indicate a lower selectivity of the SeNrs action. [ABSTRACT FROM AUTHOR]

With the help of laser ablation, a technology for obtaining nanosized crystalline selenium particles (SeNPs) has been created. The SeNPs do not exhibit significant toxic properties, in contrast to molecular selenium compounds. The administration of SeNPs can significantly increase the viabilities of SH-SY5Y and PCMF cells after radiation exposure. The introduction of such nanoparticles into the animal body protects proteins and DNA from radiation-induced damage. The number of chromosomal breaks and oxidized proteins decreases in irradiated mice treated with SeNPs. Using hematological tests, it was found that a decrease in radiation-induced leukopenia and thrombocytopenia is observed when selenium nanoparticles are injected into mice before exposure to ionizing radiation. The administration of SeNPs to animals 5 h before radiation exposure in sublethal and lethal doses significantly increases their survival rate. The modification dose factor for animal survival was 1.2. It has been shown that the introduction of selenium nanoparticles significantly normalizes gene expression in the cells of the red bone marrow of mice after exposure to ionizing radiation. Thus, it has been demonstrated that SeNPs are a new gene-protective and radioprotective agent that can significantly reduce the harmful effects of ionizing radiation. [ABSTRACT FROM AUTHOR]

The paper investigates the physicochemical processes that occur during laser-induced breakdown in colloids of gadolinium oxide nanoparticles of different concentrations. A monotonic change in the number of optical breakdowns, the average distance between the nearest breakdowns in the track of a single laser pulse, the average plasma size of a single optical breakdown, the integral luminosity of an optical breakdown plasma flash, the intensity of acoustic signals, and the rate of formation of dissociation products—O2, H2, OH•, and H2O2—is demonstrated. It is shown that the rate of formation of chemical products of the decomposition of H2O molecules under the action of breakdown when using nanoparticles of rare earth metals, in particular, gadolinium oxide, is the highest compared to other materials. Based on one laser pulse, the rates of formation of chemical products formed during the dissociation of water during laser-induced breakdown of a colloid of gadolinium oxide nanoparticles are 13.13 nmol/pulse for H2, 5.41 nmol/pulse for O2, and 6.98 nmol/pulse for hydrogen peroxide. [ABSTRACT FROM AUTHOR]

Foodborne infections are an important global health problem due to their high prevalence and potential for severe complications. Bacterial contamination of meat during processing at the enterprise can be a source of foodborne infections. Polymeric coatings with antibacterial properties can be applied to prevent bacterial contamination. A composite coating based on fluoroplast and Ag2O NPs can serve as such a coating. In present study, we, for the first time, created a composite coating based on fluoroplast and Ag2O NPs. Using laser ablation in water, we obtained spherical Ag2O NPs with an average size of 45 nm and a ζ-potential of −32 mV. The resulting Ag2O NPs at concentrations of 0.001–0.1% were transferred into acetone and mixed with a fluoroplast-based varnish. The developed coating made it possible to completely eliminate damage to a Teflon cutting board. The fluoroplast/Ag2O NP coating was free of defects and inhomogeneities at the nano level. The fluoroplast/Ag2O NP composite increased the production of ROS (H2O2, OH radical), 8-oxogualnine in DNA in vitro, and long-lived active forms of proteins. The effect depended on the mass fraction of the added Ag2O NPs. The 0.01–0.1% fluoroplast/NP Ag2O coating exhibited excellent bacteriostatic and bactericidal properties against both Gram-positive and Gram-negative bacteria but did not affect the viability of eukaryotic cells. The developed PTFE/NP Ag2O 0.01–0.1% coating can be used to protect cutting boards from bacterial contamination in the meat processing industry. [ABSTRACT FROM AUTHOR]

The bacterial contamination of cutting boards and other equipment in the meat processing industry is one of the key reasons for reducing the shelf life and consumer properties of products. There are two ways to solve this problem. The first option is to create coatings with increased strength in order to prevent the formation of micro damages that are favorable for bacterial growth. The second possibility is to create materials with antimicrobial properties. The use of polytetrafluoroethylene (PTFE) coatings with the addition of metal oxide nanoparticles will allow to the achieving of both strength and bacteriostatic effects at the same time. In the present study, a new coating based on PTFE and Fe2O3 nanoparticles was developed. Fe2O3 nanoparticles were synthesized by laser ablation in water and transferred into acetone using the developed procedures. An acetone-based colloidal solution was mixed with a PTFE-based varnish. Composites with concentrations of Fe2O3 nanoparticles from 0.001–0.1% were synthesized. We studied the effect of the obtained material on the generation of ROS (hydrogen peroxide and hydroxyl radicals), 8-oxoguanine, and long-lived active forms of proteins. It was found that PTFE did not affect the generation of all the studied compounds, and the addition of Fe2O3 nanoparticles increased the generation of H2O2 and hydroxyl radicals by up to 6 and 7 times, respectively. The generation of 8-oxoguanine and long-lived reactive protein species in the presence of PTFE/Fe2O3 NPs at 0.1% increased by 2 and 3 times, respectively. The bacteriostatic and cytotoxic effects of the developed material were studied. PTFE with the addition of Fe2O3 nanoparticles, at a concentration of 0.001% or more, inhibited the growth of E. coli by 2–5 times compared to the control or PTFE without NPs. At the same time, PTFE, even with the addition of 0.1% Fe2O3 nanoparticles, did not significantly impact the survival of eukaryotic cells. It was assumed that the resulting composite material could be used to cover cutting boards and other polymeric surfaces in the meat processing industry. [ABSTRACT FROM AUTHOR]

The problem of bacterial contamination through surfaces is important for the food industry. In this regard, there is a growing interest in new coatings based on nanoparticles that can provide a long-term antibacterial effect. Aluminum oxide nanoparticles are a good candidate for such coatings due to their availability and good biocompatibility. In this study, a coating containing aluminum oxide nanoparticles was produced using polytetrafluoroethylene as a polymer matrix—a polymer that exhibits excellent mechanical and physicochemical properties and it is not toxic. The obtained coatings based on "liquid Teflon" containing various concentrations of nanoparticles (0.001–0.1 wt%) prevented the bacterial growth, and they did not exhibit a cytotoxicity on animal cells in vitro. Such coatings are designed not only to provide an antibacterial surface effect, but also to eliminate micro damages on surfaces that inevitably occur in the process of food production. [ABSTRACT FROM AUTHOR]