Se Nanoparticles Research Articles

Selenite Bioremediation by Food-Grade Probiotic Lactobacillus casei ATCC 393: Insights from Proteomics Analysis.

Microorganisms capable of converting toxic selenite into elemental selenium (Se0) are considered an important and effective approach for bioremediation of Se contamination. In this study, we investigated the mechanism of reducing selenite to Se0 and forming Se nanoparticles (SeNPs) by food-grade probiotic Lactobacillus casei ATCC 393 (L. casei ATCC 393) through proteomics analysis. The results showed that selenite added during the exponential growth period of bacteria has the highest reduction efficiency, and 4.0 mM selenite decreased by nearly 95% within 72 h and formed protein-capped-SeNPs. Proteomics analysis revealed that selenite induced a significant increase in the expression of glutaredoxin, oxidoreductase, and ATP binding cassette (ABC) transporter, which can transport glutathione (GSH) and selenite. Selenite treatment significantly increased the CydC and CydD (putative cysteine and glutathione importer, ABC transporter) mRNA expression level, GSH content, and GSH reductase activity. Furthermore, supplementation with an additional GSH significantly increased the reduction rate of selenite, while GSH depletion significantly inhibited the reduction of selenite, indicating that GSH-mediated Painter-type reaction may be the main pathway of selenite reduction in L. casei ATCC 393. Moreover, nitrate reductase also participates in the reduction process of selenite, but it is not the primary factor. Overall, L. casei ATCC 393 effectively reduced selenite to SeNPs by GSH and nitrate reductase-mediated reduction pathway, and the GSH pathway played the decisive role, which provides an environmentally friendly biocatalyst for the bioremediation of Se contamination. IMPORTANCE Due to the high solubility and bioavailability of selenite, and its widespread use in industrial and agricultural production, it is easy to cause selenite to accumulate in the environment and reach toxic levels. Although the bacteria screened from special environments have high selenite tolerance, their safety has not been fully verified. It is necessary to screen out strains with selenite-reducing ability from nonpathogenic, functionally known, and widely used strains. Herein, we found food-grade probiotic L. casei ATCC 393 effectively reduced selenite to SeNPs by GSH and nitrate reductase-mediated reduction pathway, which provides an environmentally friendly biocatalyst for the bioremediation of Se contamination.

Selenium Nanoparticles Show Anticancer Activity Through Regulation of HIF-1α and HIF-2α Under Hypoxic Condition in Liver Cancer Cells.

Tumor microenvironment has significant influence in therapeutic response and clinical outcome. Combination therapy is more effective in cancer treatment compared with monotherapy. Any chemical or drug that targets tumor microenvironment pathway, will be a boon to combination cancer chemotherapy. Combination therapy through micronutrient may have added advantage in clinical applications. Selenium (Se) is an essential micronutrient; Se in the form of Se nanoparticles (SeNPs) show efficient anticancer properties and may have the potential to target tumor niche such as hypoxic environment. The aim of this study was to find out the anticancer effect of SeNPs on cell line HepG2 under hypoxic condition and also to evaluate their effect on the translocation of hypoxia-inducible factors (HIFs) from cytoplasm to nucleus that help the cells to survive under hypoxic condition. It was found that the SeNPs induce HepG2 cell death in normoxic and hypoxic conditions, however, hypoxic condition showed higher LD50. SeNP concentration is directly proportional to cell death in both the conditions. Furthermore, intracellular accumulation of Se is not affected by hypoxia. SeNP-induced HepG2 cell death is due to increased DNA damage, nuclear condensation, and mitochondrial membrane potential disturbance. Furthermore, SeNPs were also found to decrease the translocation of HIFs from cytosol to the nucleus. After analyzing the results, it is concluded that SeNP treatment disturbs tumor niche through the inhibition of HIFs' translocation from cytosol to nucleus. SeNPs in synergy with primary drug, such as doxorubicin (DOX), may enhance the anticancer efficacy of DOX through regulation of HIFs, warranting further research.

Microbiota-Liver-Bile Salts Axis, a Novel Mechanism Involved in the Contrasting Effects of Sodium Selenite and Selenium-Nanoparticle Supplementation on Adipose Tissue Development in Adolescent Rats.

Adolescence is a period during which body composition changes deeply. Selenium (Se) is an excellent antioxidant trace element related to cell growth and endocrine function. In adolescent rats, low Se supplementation affects adipocyte development differently depending on its form of administration (selenite or Se nanoparticles (SeNPs). Despite this effect being related to oxidative, insulin-signaling and autophagy processes, the whole mechanism is not elucidated. The microbiota-liver-bile salts secretion axis is related to lipid homeostasis and adipose tissue development. Therefore, the colonic microbiota and total bile salts homeostasis were explored in four experimental groups of male adolescent rats: control, low-sodium selenite supplementation, low SeNP supplementation and moderate SeNPs supplementation. SeNPs were obtained by reducing Se tetrachloride in the presence of ascorbic acid. Supplementation was received orally through water intake; low-Se rats received twice more Se than control animals and moderate-Se rats tenfold more. Supplementation with low doses of Se clearly affected anaerobic colonic microbiota profile and bile salts homeostasis. However, these effects were different depending on the Se administration form. Selenite supplementation primarily affected liver by decreasing farnesoid X receptor hepatic function, leading to the accumulation of hepatic bile salts together to increase in the ratio Firmicutes/Bacteroidetes and glucagon-like peptide-1 (GLP-1) secretion. In contrast, low SeNP levels mainly affected microbiota, moving them towards a more prominent Gram-negative profile in which the relative abundance of Akkermansia and Muribaculaceae was clearly enhanced and the Firmicutes/Bacteroidetes ratio decreased. This bacterial profile is directly related to lower adipose tissue mass. Moreover, low SeNP administration did not modify bile salts pool in serum circulation. In addition, specific gut microbiota was regulated upon administration of low levels of Se in the forms of selenite or SeNPs, which are properly discussed. On its side, moderate-SeNPs administration led to great dysbiosis and enhanced the abundance of pathogenic bacteria, being considered toxic. These results strongly correlate with the deep change in adipose mass previously found in these animals, indicating that the microbiota-liver-bile salts axis is also mechanistically involved in these changes.

A novel Ni0.85Se/MoSSe heterojunction demonstrated omnipotent boosting catalytic ability in photocatalysis, photoelectrochemistry and electrocatalysis

A new type II 0D/3D Ni0.85Se/MoSSe heterojunction photocatalyst was prepared via a hydrothermal method. These Ni0.85Se/MoSSe heterojunction photocatalysts exhibited outstanding catalytic performance in photocatalysis, electrocatalysis and photoelectrochemistry. By optimizing the composited ratio of MoSSe, the catalyst showed a photocurrent density of 32.95 μA/cm2 which was 4.23 and 32.95 times that of pure Ni0.85Se and MoSSe, respectively. In the degradation of tetracycline hydrochloride, it displayed the largest degradation rate, boosting it 2.81 and 10.3 times that of Ni0.85Se and MoSSe, respectively. In hydrogen evolution reaction and oxygen evolution reaction, the Ni0.85Se/MoSSe heterojunction photocatalyst had Tafel slope of 58 and 37 mV/dec, respectively, which were both much lower than Ni0.85Se (77 and 171 mV/dec) and MoSSe (102 and 389 mV/dec). With structure and morphology analysis, the MoSSe has a 3D reticular structure which is more suitable for loading 0D Ni0.85Se nanoparticles to construct a 0D/3D heterostructure, where carriers generated in Ni0.85Se will be easily collected by MoSSe to accelerate the carriers’ separation and transmission. Moreover, the conduction band and valance band of MoSSe are both lower than those of Ni0.85Se, forming a type-II heterojunction where photoinduced electrons and holes will be separated to different sites. Thus, oxidation and reduction reactions will occur in different locations to demonstrate outstanding catalytic performance.

Time-Resolved Examination of Fungal Selenium Redox Transformations.

Selenium (Se) is both a micronutrient required for most life and an element of environmental concern due to its toxicity at high concentrations, and both bioavailability and toxicity are largely influenced by the Se oxidation state. Environmentally relevant fungi have been shown to aerobically reduce Se(IV) and Se(VI), the generally more toxic and bioavailable Se forms. The goal of this study was to shed light on fungal Se(IV) reduction pathways and biotransformation products over time and fungal growth stages. Two Ascomycete fungi were grown with moderate (0.1 mM) and high (0.5 mM) Se(IV) concentrations in batch culture over 1 month. Fungal growth was measured throughout the experiments, and aqueous and biomass-associated Se was quantified and speciated using analytical geochemistry, transmission electron microscopy (TEM), and synchrotron-based X-ray absorption spectroscopy (XAS) approaches. The results show that Se transformation products were largely Se(0) nanoparticles, with a smaller proportion of volatile, methylated Se compounds and Se-containing amino acids. Interestingly, the relative proportions of these products were consistent throughout all fungal growth stages, and the products appeared stable over time even as growth and Se(IV) concentration declined. This time-series experiment showing different biotransformation products throughout the different growth phases suggests that multiple mechanisms are responsible for Se detoxification, but some of these mechanisms might be independent of Se presence and serve other cellular functions. Knowing and predicting fungal Se transformation products has important implications for environmental and biological health as well as for biotechnology applications such as bioremediation, nanobiosensors, and chemotherapeutic agents.

Autocatalysis surface-growth of Co0.85Se@carbon nanotubes on carbon nanosheets as anode material for superior lithium storage

Cobalt selenide compounds are regarded as attractive anode materials for lithium-ion batteries. However, problems like as sluggish kinetics and volume change during repeated intercalation/deintercalation of Li+ severely limit their uses. In this work, a simple pyrolysis-selenization method is used to fabricate mixed-dimensional N-doped Co0.85Se@carbon nanotubes on carbon nanosheet (N-doped Co0.85Se@CNTs/C). The autocatalysis mechanism causes the curled carbon nanotubes to form on the carbon nanosheets. A small number of Co0.85Se nanoparticles are enclosed in the tops of carbon nanotubes, with the rest strewn on the surface of carbon nanosheets. Each component's synergistic contribution provides various ion/electron accessible paths as well as satisfying surface capacitive contributions, result in increased lithium storage performance. The N-doped Co0.85Se@CNTs/C composites exhibit excellent rate performance (596.6 mA h g−1 at 5 A g−1) and superb cycling performance (701.2 mA h g−1 after 600 cycles at 1 A g−1), as expected. This work shows that the construction of interface interaction may offer an alternative selection of anode materials based on rationally design for superior Lithium storage performance.

Biosorption performance of the multi-metal tolerant fungus Aspergillus sp. for removal of some metallic nanoparticles from aqueous solutions

The wide spread of nanotechnology applications currently carries with it the possibility of polluting the environment with the residues of these nanomaterials, especially those in the metallic form. Therefore, it is necessary to study the possibility of treating and removing various nanoscale metal pollutants in environmentally friendly ways. The present study focused on the isolation of multi-metal tolerant fungi to be applied in the bioremoval of Zn, Fe, Se, and Ag nanoparticles as potential nanoscale metal pollutants. Aspergillus sp. has been isolated as multi-metal tolerant fingus and investigated in the bioremoval of targeted nanometals from their aquoues solutions. The effect of biomass age, pH, and contact time was studied to determine the optimal biosorption conditions for fungal pellets towards metal NPs. The results showed a high percentage of fungal biosorption on the of two-day-old cells, which amounted to 39.3, 52.2, 91.7, and 76.8% of zinc, iron, selenium, and silver, respectively. The pH 7 was recorded the highest percentage of NPs removal for the four studied metals i.e. 38.8, 68.1, 80.4, and 82.0% of Zn-, Fe-, Se- and Ag-NPs, respectively. The contact time required between Aspergillus sp. and the metal nanoparticles to obtain the best adsorption was only 10 min in the case of Zn and Ag, but it was 40 min for both Fe and Se NPs. The efficiency of living fungal pellets in removing the four metallic NPs exceeded that of dead biomass by 1.8, 5.7, 2.5, and 2.5 folds for Zn, Fe, Se and Ag, respectively. However, utilization of dead fungal biomass for metallic NPs removal could be considered more applicable to the actual environmental applications.

Cu2−x Se nanoparticles suppress cell proliferation and migration in hepatocellular carcinoma by impairing mitochondrial respiration

Cu2−x Se nanoparticles (Cu2−x Se NPs) as a new therapeutic drug platform is widely used in disease treatment due to their strong near-infrared optical absorption. In recent years, with their continuous expansion of applications in different fields, their own biological effects have received increasing attention. However, little is known about the effect of Cu2−x Se NPs on cancer cell. In this research, we found that Cu2−x Se NPs inhibited proliferation of HepG2 cells (IC50: 15.91 μM) and SMMC-7721 cells (IC50: 43.15 μM) and they mainly induced cell cycle arrest at the G2/M phase. Moreover, Cu2−x Se NPs inhibited HepG2 and SMMC-7721 cell migration and lamellopodia formation. Further studies indicated that Cu2−x Se NPs impaired mitochondrial respiration by inhibiting electron transport chain complex activity, thus reducing adenosine triphosphate levels. The insufficient energy supply subsequently impaired actin cytoskeleton assembly, ultimately inhibiting HepG2 and SMMC-7721 cell proliferation and migration. These findings suggest that Cu2−x Se NPs may have potentially antitumor activity, which might provide new insights of NPs into specific cancer treatment.

Elucidation of the effect of hybrid copper/selenium nanofiller on the optical, thermal, electrical, mechanical properties and antibacterial activity of polyvinyl alcohol/carboxymethyl cellulose blend

AbstractPolymer nanocomposite samples of a polyvinyl alcohol (PVA)/carboxymethyl cellulose (CMC) blend doped with copper nanoparticles and selenium nanoparticles (Cu NPs/Se NPs) were prepared by the casting method. X‐ray diffraction analysis (XRD) patterns showed an increase in the degree of amorphous nature of the host polymeric matrix with increasing content of Cu/Se nanoparticles. The addition of 1.60 wt.%, Cu/Se NPs narrowed the indirect optical energy gap value of the nanocomposite from 3.97 to 2.39 eV. In addition, the differential scanning calorimetry (DSC) curve of the pure blend displays the miscibility of the blend components, confirmed by the presence of a single glass transition. Transmission electron microscopy (TEM) micrographs showed that the average sizes of Cu and Se nanoparticles are about 11 and 41 nm, respectively. The maximum values of AC and DC conductivity were 6.76 × 10−6 S.cm−1 and 5.49 × 10−10 for a PVA/CMC film filled with 1.60 wt.% of Cu‐Se NPs. The mechanical properties of the PVA/CMC blend improved after adding the hybrid NPs. Moreover, the antibacterial activity of the prepared samples was increased due to the filling of Cu‐Se nanoparticles to the films. Therefore, these results indicate the multifunctionality of PVA/CMC/Cu‐Se nanocomposite samples for use in electrical energy storage, solid‐polymer electrolytes, and food packaging industry.

Evaluation of nano-selenium biofortification characteristics of alfalfa (Medicago sativa L.)

Abstract Selenium (Se) is indispensable for animals and humans. One option to address Se deficiency is to biofortify plants with Se. Biofortification of forage with Se nanoparticles (NPs) is gaining more attention as an efficient and safe source of Se for livestock. The purpose of this study was to investigate the effect of different concentrations of NPs-Se (0, 30, 50, 100, 150, and 250 mg·L−1) on the growth of alfalfa harvested multiple times, and to provide a basis for the production of Se-enriched forages. Applying 50 mg·L−1 concentration of NPs-Se had the best effect on yield over three harvests. Over three harvests, low-dose NPs-Se (30 and 50 mg·L−1) application significantly increased peroxidase and superoxide dismutase activities, chlorophyll content and carotenoid content, and significantly decreased malondialdehyde content. The total Se content and Se accumulation in plants at the same harvest showed an upward trend with increasing Se concentration. At the same concentration, from first harvest to third harvest, Se content and Se accumulation showed an initially increasing and then decreasing trend. The evaluation found that foliar application of NPs-Se at 50 mg·L−1 could have the greatest positive effect on the growth and yield of multiple-harvested alfalfa.

The role of selenium and nano selenium on physiological responses in plant: a review.

Selenium (Se), being an essential micronutrient, enhances plant growth and development in trace amounts. It also protects plants against different abiotic stresses by acting as an antioxidant or stimulator in a dose-dependent manner. Knowledge of Se uptake, translocation, and accumulation is crucial to achieving the inclusive benefits of Se in plants. Therefore, this review discusses the absorption, translocation, and signaling of Se in plants as well as proteomic and genomic investigations of Se shortage and toxicity. Furthermore, the physiological responses to Se in plants and its ability to mitigate abiotic stress have been included. In this golden age of nanotechnology, scientists are interested in nanostructured materials due to their advantages over bulk ones. Thus, the synthesis of nano-Se or Se nanoparticles (SeNP) and its impact on plants have been studied, highlighting the essential functions of Se NP in plant physiology. In this review, we survey the research literature from the perspective of the role of Se in plant metabolism. We also highlight the outstanding aspects of Se NP that enlighten the knowledge and importance of Se in the plant system.

The anti-angiogenesis and antioxidant activity of chitosan-mediated synthesized selenium-gold nanostructure

A novel nanocomposite containing selenium-gold-chitosan (Se-Au-CS) was prepared and characterized using powder X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), UV–Vis spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDX) and transmission electron microscopy (TEM). The powder X-ray diffraction has shown successful synthesis of Se nanoparticles. To further study the presence of gold nanoparticles, EDX and UV–Vis were used. The morphological studies and grain sizes have revealed polyhedral shapes with a mean particle size of ≈211 nm. The TEM images also indicated the presence of nanoparticles in the CS coating. The Anti-oxidant effects of Se-Au-CS were evaluated using the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay. Moreover, in the chorioallantoic membrane (CAM) assay, notable anti-angiogenesis effects were observed for Se-Au-CS. The results of this study demonstrated effective anti-angiogenesis effects of Se-Au-CS were evaluated using CAM assay for the first time. It also indicated the application of Se-Au-CS could be extended to the treatment of various cancer diseases.

Turning carbon dots into selenium bearing nanoplatforms with in vitro GPx-like activity and pro-oxidant activity

Selenium (Se) has been defined as the “Janus element”, with one face showing antioxidant activity and the other pro-oxidant activity. The biological effect of Se depends on both dose and speciation. Se nanoparticles are attracting major interest, although their large-scale preparation for biomedical applications is not trivial. We hypothesize that acid anhydride-coated carbon dots (AA-CD) are an attractive platform for preparing nanoparticles containing chemically defined Se. The reaction of AA-CD with 3-selenocyanatopropan-1-amine yields carbon dots bearing selenocyanate and carboxylate groups (CD-SeCN) that allow for tuning the hydrosolubility. CD-SeCN has a Se content of 0.36 µmol per mg of nanoparticles, and they show the typical photoluminescence of carbon dots. The selenocyanate groups (SeCN) exhibited glutathione peroxidase-like activity and cytotoxicity. Data show that antioxidant behavior differs between normal and tumor cells, and the evaluation on HEK293 and A549 cells reveals that the toxicity of CD-SeCN depends on dose, time, and intracellular glutathione (GSH) content. The toxicity of CD-SeCN decreases with the time of incubation and the cell death mechanism switches from necrosis to apoptosis, indicating that CD-SeCN is neutralized. Additionally, high levels of intracellular GSH exert a protective effect. These results support a pharmacological potential in cancers with low levels of intracellular GSH. The use of AA-CD as nanoplatforms is a general strategy that paves the way for the engineering of advanced nanosystems.

Nanofungicides with Selenium and Silicon Can Boost the Growth and Yield of Common Bean (Phaseolus vulgaris L.) and Control Alternaria Leaf Spot Disease.

There is an urgent need to reduce the intensive use of chemical fungicides due to their potential damage to human health and the environment. The current study investigated whether nano-selenium (nano-Se) and nano-silica (nano-SiO2) could be used against the leaf spot disease caused by Alternaria alternata in a common bean (Phaseolus vulgaris L.). The engineered Se and SiO2 nanoparticles were compared to a traditional fungicide and a negative control with no treatment, and experiments were repeated during two successive seasons in fields and in vitro. The in vitro study showed that 100 ppm nano-Se had an efficacy rate of 85.1% on A. alternata mycelial growth, followed by the combined applications (Se + SiO2 at half doses) with an efficacy rate of 77.8%. The field study showed that nano-Se and the combined application of nano-Se and nano-SiO2 significantly decreased the disease severity of A. alternata. There were no significant differences among nano-Se, the combined application, and the fungicide treatment (positive control). As compared to the negative control (no treatment), leaf weight increased by 38.3%, the number of leaves per plant by 25.7%, chlorophyll A by 24%, chlorophyll B by 17.5%, and total dry seed yield by 30%. In addition, nano-Se significantly increased the enzymatic capacity (i.e., CAT, POX, PPO) and antioxidant activity in the leaves. Our current study is the first to report that the selected nano-minerals are real alternatives to chemical fungicides for controlling A. alternata in common beans. This work suggests the potential of nanoparticles as alternatives to fungicides. Further studies are needed to better understand the mechanisms and how different nano-materials could be used against phytopathogens.

Foliar application of silicon, selenium, and zinc nanoparticles can modulate lead and cadmium toxicity in sage (Salvia officinalis L.) plants by optimizing growth and biochemical status

Different techniques have been used to alleviate metal toxicity in medicinal plants; accordingly, nanoparticles (NPs) have a noticeable interest in modulating oxidative stresses. Therefore, this work aimed to compare the impacts of silicon (Si), selenium (Se), and zinc (Zn) NPs on the growth, physiological status, and essential oil (EO) of sage(Salvia officinalis L.)treated with foliar application of Si, Se, and Zn NPs upon lead (Pb) and cadmium (Cd) stresses. The results showed that Se, Si, and Zn NPs decreased Pb accumulation by 35, 43, and 40%, and Cd concentration by 29, 39, and 36% in sage leaves. Shoot plant weight showed a noticeable reduction upon Cd (41%) and Pb (35%) stress; however, NPs, particularly Si and Zn improved plant weight under metal toxicity. Metal toxicity diminished relative water content (RWC) and chlorophyll, whereas NPs significantly enhanced these variables. The noticeable raises in malondialdehyde (MDA) and electrolyte leakage (EL) were observed in plants exposed to metal toxicity; however, they were alleviated with foliar application of NPs. The EO content and EO yield of sage plants decreased by the heavy metals but increased by the NPs. Accordingly, Se, Si, and Zn NPS elevated EO yield by 36, 37, and 43%, respectively, compared with non-NPs. The primary EO constituents were 1,8-cineole (9.42-13.41%), α-thujone (27.40-38.73%), β-thujone (10.11-12.94%), and camphor (11.31-16.45%). This study suggests that NPs, particularly Si and Zn, boosted plant growth by modulating Pb and Cd toxicity, which could be advantageous for cultivating this plant in areas with heavy metal-polluted soils.

Selenium speciation determines the angiogenesis effect through regulating selenoproteins to trigger ROS-mediated cell apoptosis and cell cycle arrest

Tumor angiogenesis is closely related to tumor development, immune escape, and drug resistance. Therefore, the development of effective anti-tumor angiogenesis drugs is of great research significance. Although the current clinical angiogenesis inhibitors have achieved certain efficacy, they also pose the problems of limited and short duration of efficacy, drug resistance, and intrinsic toxicity. Anti-tumor angiogenesis strategies targeting endothelial cells (ECs) have attracted widespread attention in the development of highly effective and low toxicity anti-angiogenesis inhibitors. Studies have verified that the trace element selenium (Se) can inhibit tumor growth by inhibiting tumor angiogenesis through different mechanisms. Nevertheless, it is unclear whether Se speciation has different effects on anti-tumor angiogenesis. Herein, we found that Se exhibited effective anti-angiogenic activity, and its mechanisms of activity were determined by its chemical speciation. Organic Se can significantly inhibit tumor angiogenesis by targeting thioredoxin reductase (TrxR) to trigger cell apoptosis and cell cycle arrest and by increasing reactive oxygen species (ROS) production in ECs. Inorganic Se can induce cell cycle arrest and increase ROS production in ECs, showing promising anti-angiogenic effects. Se nanoparticles (SeNPs) slightly inhibit tumor angiogenesis by inducing apoptosis and cell cycle arrest and by increasing the production of ROS. In summary, this study elucidates the anti-angiogenic activity of Se speciation control with a view to providing a scientific reference for the design and development of novel Se-based highly effective and low toxicity angiogenesis inhibitors.

Improvement on the Use of Se@C in Batteries by Synergistic Effect of Nano-Confinement and C-Se Bond

In order to alleviate the cyclic attenuation caused by the dissolution of poly-selenides in lithium/sodium storage devices, quantitative selenium was slowly evaporated on the surface of sodium citrate derived carbon (SCDC) at low temperature, and simultaneously the element Se was doped. Benefiting from the synergistic effects of the domain-limiting effect of embedded nanopores on Se nanoparticles and the stability of SCDC with Se doped during the embedding and stripping of Na ions, Se@C versus sodium metal exhibits high second specific capacity of 485 mAh·g−1 and unexpected stability at 0.1 A g−1 and 1 A g−1. Se@C versus lithium metal exhibits high second specific capacity of 1185 mAh·g−1 at 0.1 A g−1 and excellent stability. Together with the simple and application of synthesis method, Se@C composite is expected to become an anode material for large sodium/lithium storage devices.

A Recent Update on the Impact of Nano-Selenium on Plant Growth, Metabolism, and Stress Tolerance

Selenium (Se) is a microelement that plays an important nutrient role by influencing various physiological and biochemical traits in plants. It has been shown to stimulate plant metabolism, enhancing secondary metabolites and lowering abiotic and biotic stress in plants. Globally, the enormous applications of nanotechnology in the food and agricultural sectors have vastly expanded. Nanoselenium is more active than bulk materials, and various routes of synthesis of Se nanoparticles (Se-NPs) have been reported in which green synthesis using plants is more attractive due to a reduction in ecological issues and an increase in biological activities. The Se-NP-based biofortification is more significant because it increases plant stress tolerance and positively impacts their metabolism. Se-NPs can enhance plant resistance to various oxidative stresses, promote growth, enhance soil nutrient status, enhance plant antioxidant levels, and participate in the transpiration process. Additionally, they use a readily available, biodegradable reducing agent and are ecologically friendly. This review concentrates on notable information on the different modes of Se-NPs' synthesis and characterization, their applications in plant growth, yield, and stress tolerance, and their influence on the metabolic process.

Pivotal biological processes and proteins for selenite reduction and methylation in Ganoderma lucidum.

Microbial transformations, especially the reduction and methylation of Se oxyanion, have gained significance in recent years as effective detoxification methods. Ganoderma lucidum is a typical Se enrichment resource that can reduce selenite to elemental Se and volatile Se metabolites under high selenite conditions. However, the detailed biological processes and reduction mechanisms are unclear. In this study, G. lucidum reduced selenite to elemental Se and further aggregated it into Se nanoparticles with a diameter of <200nm, simultaneously accompanied by the production of pungent, odorous, and volatile methyl-selenium metabolites. Tandem mass tag-based quantitative proteomic analysis revealed thioredoxin 1, thioredoxin reductase (NADPH), glutathione reductase, 5-methyltetrahydropteroyltriglutamate-homocysteine methyltransferase, and cystathionine gamma-lyase as proteins involved in selenite reduction and methylation. Furthermore, the high expression of proteins associated with cell structures that prompted cell lysis may have facilitated Se release. The upregulation of proteins involved in the defense reactions was also detected, reflecting their roles in the self-defense mechanism. This study provides novel insights into the vital role of G. lucidum in mediating Se transformation in the biogeochemical Se cycle and contributes to the application of fungi in Se bioremediation.

Comparison of Nutritional Availability of Biogenic Selenium Nanoparticles and Chemically Synthesized Selenium Nanoparticles.

Selenium (Se) is an essential micronutrient, and animals biosynthesize selenoproteins from various selenocompounds such as inorganic salts and organic selenocompounds as a Se source. In addition to the inorganic and organic forms of Se, it is also known that elemental Se is biologically synthesized at the nanoscale in nature. Biologically synthesized Se nanoparticles (Se-NPs), i.e., biogenic Se-NPs (Se-BgNPs), have not been fully investigated as a Se source compared with the other forms of Se. In this study, we evaluated the nutritional availability of Se-BgNPs biosynthesized in E. coli and revealed that Se-BgNPs were less assimilated into selenoproteins in rats as a Se source than inorganic Se salt or chemically synthesized Se-NPs. Se-BgNPs showed tolerance toward digestion and low absorbability in gut, which resulted in the low nutritional availability. Se-BgNPs seem to be coated with a biomaterial that functions to reduce their toxicity toward E. coli and at the same time lowers their availability to animals.