Single-cell ICP-MS for evaluating the Se-protective effect against MeHg+-induced neurotoxicity in human neuroblastoma cell line (SH-SY5Y)

The protective effect of selenium (Se) against Hg-induced neurotoxicity has been widely investigated; however, the mechanisms behind this interaction have not been fully elucidated yet. In the current work, the role of Se against MeHg+-induced cytotoxicity in the human neuroblastoma cell line (SH-SY5Y) is reported for the first time by tracking Hg uptake and accumulation at the single-cell level by inductively coupled plasma-mass spectrometry in single-cell mode (SC-ICP-MS). The influence of different Se species (SeMet, SeMeSeCys, citrate-SeNPs, and chitosan-SeNPs) on MeHg+ cytotoxicity was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. SeMet and SeMeSeCys exhibited protective effects against MeHg+-induced cell death, particularly at high MeHg+ concentrations (LC50). In addition, chitosan-SeNPs showed greater protection compared to citrate-SeNPs when co-exposed with MeHg+. Interestingly, SC-ICP-MS unveiled the heterogeneous distribution of Hg uptake by SH-SY5Y cells. Co-exposure of SeMet and SeMeSeCys with MeHg+ led to a reduction of the amount of Hg accumulated per individual cell, which decreased the maximum level of Hg per cell by half (from 60 fg Hg cell-1 to 30 fg Hg cell-1) when SeMet was present, along with a decrease in the percentage of cells that accumulated the highest quantity of MeHg+. All these data corroborate the protective role of Se against Hg toxicity at the cellular level.

Microplastic-induced NAFLD: Hepatoprotective effects of nanosized selenium

Polystyrene microplastics (MPs) are persistent environmental pollutants commonly encountered in daily human life. Numerous studies have demonstrated their ability to induce liver damage, including oxidative stress, inflammation, and lipid accumulation. However, limited information exists regarding preventive measures against this issue. In our study, we investigated the potential preventive role of selenium nanoparticles (YC-3-SeNPs) derived from Yak-derived Bacillus cereus, a novel nanobiomaterial known for its antioxidant properties and lipid metabolism regulation. Using transcriptomic and metabolomic analyses, we identified key genes and metabolites associated with oxidative stress and lipid metabolism imbalance induced by MPs. Upregulated genes (Scd1, Fasn, Irs2, and Lpin) and elevated levels of arachidonic and palmitic acid accumulation were observed in MP-exposed mice, but not in those exposed to SeNPs. Further experiments confirmed that SeNPs significantly attenuated liver lipid accumulation and degeneration caused by MPs. Histological results and pathway screening validated our findings, revealing that MPs suppressed the Pparα pathway and Nrf2 pathway, whereas SeNPs activated both pathways. These findings suggest that MPs may contribute to the development of nonalcoholic fatty liver disease (NAFLD), while SeNPs hold promise as a future nanobio-product for its prevention.

Improved titer and stability of selenium nanoparticles produced by engineered Saccharomyces cerevisiae

Selenium nanoparticles (SeNPs) have gained significant attention in the fields of medicine and healthcare products due to their various biological activities and low toxicity. In this study, we focused on genetically modifying the Saccharomyces cerevisiae strain YW16 (CICC 1406), which has the ability to efficiently reduce sodium selenite and produce red SeNPs. By overexpressing genes involved in glutathione production, we successfully increased the glutathione titer of the modified strain YJ003 from 41.0 mg/L to 212.0 mg/L. Moreover, we improved the conversion rate of 2.0 g/L sodium selenite from 49.3% to 59.6%. Furthermore, we identified three surface proteins of SeNPs, and found that overexpression of Act1, one of the identified proteins, led to increased stability of SeNPs across different acid-base and temperature conditions. Through a 135-h feed fermentation process using 5.0 g/L sodium selenite, we achieved an impressive conversion rate of 88.7% for sodium selenite, and each gram of SeNPs contained 195.7 mg of selenium. Overall, our findings present an efficient method for yeast to synthesize SeNPs with high stability. These SeNPs hold great potential for applications in nanomedicine or as nutritional supplements to address selenium deficiency.

Combinational therapy with Myc decoy oligodeoxynucleotides encapsulated in nanocarrier and X-irradiation on breast cancer cells

The Myc gene is the essential oncogene in triple-negative breast cancer (TNBC). This study investigates the synergistic effects of combining Myc decoy oligodeoxynucleotides-encapsulated niosomes-selenium hybrid nanocarriers with X-irradiation exposure on the MDA-MB-468 cell line. Decoy and scramble ODNs for Myc transcription factor were designed and synthesized based on promoter sequences of the Bcl2 gene. The nanocarriers were synthesized by loading Myc ODNs and selenium into chitosan (Chi-Se-DEC), which was then encapsulated in niosome-nanocarriers (NISM@Chi-Se-DEC). FT-IR, DLS, FESEM, and hemolysis tests were applied to confirm its characterization and physicochemical properties. Moreover, cellular uptake, cellular toxicity, apoptosis, cell cycle, and scratch repair assays were performed to evaluate its anticancer effects on cancer cells. All anticancer assessments were repeated under X-ray irradiation conditions (fractionated 2Gy). Physicochemical characteristics of niosomes containing SeNPs and ODNs showed that it is synthesized appropriately. It revealed that the anticancer effect of NISM@Chi-Se-DEC can be significantly improved in combination with X-ray irradiation treatment. It can be concluded that NISM@Chi-Se-DEC nanocarriers have the potential as a therapeutic agent for cancer treatment, particularly in combination with radiation therapy and in-vivo experiments are necessary to confirm the efficacy of this nano-drug.

Combining Porous Se@SiO2 Nanocomposites and dECM Enhances the Myogenic Differentiation of Adipose-Derived Stem Cells

Background

Volumetric Muscle Loss (VML) denotes the traumatic loss of skeletal muscle, a condition that can result in chronic functional impairment and even disability. While the body can naturally repair injured skeletal muscle within a limited scope, patients experiencing local and severe muscle loss due to VML surpass the compensatory capacity of the muscle itself. Currently, clinical treatments for VML are constrained and demonstrate minimal efficacy. Selenium, a recognized antioxidant, plays a crucial role in regulating cell differentiation, anti-inflammatory responses, and various other physiological functions.

Methods

We engineered a porous Se@SiO2 nanocomposite (SeNPs) with the purpose of releasing selenium continuously and gradually. This nanocomposite was subsequently combined with a decellularized extracellular matrix (dECM) to explore their collaborative protective and stimulatory effects on the myogenic differentiation of adipose-derived mesenchymal stem cells (ADSCs). The influence of dECM and NPs on the myogenic level, reactive oxygen species (ROS) production, and mitochondrial respiratory chain (MRC) activity of ADSCs was evaluated using Western Blot, ELISA, and Immunofluorescence assay.

Results

Our findings demonstrate that the concurrent application of SeNPs and dECM effectively mitigates the apoptosis and intracellular ROS levels in ADSCs. Furthermore, the combination of dECM with SeNPs significantly upregulated the expression of key myogenic markers, including MYOD, MYOG, Desmin, and myosin heavy chain in ADSCs. Notably, this combination also led to an increase in both the number of mitochondria and the respiratory chain activity in ADSCs.

Conclusion

The concurrent application of SeNPs and dECM effectively diminishes ROS production, boosts mitochondrial function, and stimulates the myogenic differentiation of ADSCs. This study lays the groundwork for future treatments of VML utilizing the combination of SeNPs and dECM.

Ascorbic acid and selenium nanoparticles synergistically interplay in chromium stress mitigation in rice seedlings by regulating oxidative stress indicators and antioxidant defense mechanism

Ascorbic acid (AsA) and selenium nanoparticles (SeNPs) were versatile plant growth regulators, playing multiple roles in promoting plant growth under heavy metal stresses. This study aimed to evaluate the beneficial role of individual and combined effects of AsA and SeNPs on morpho-physio-biochemical traits of rice with or without chromium (Cr) amendment. The results indicated that Cr negatively affected plant biomass, gas exchange parameters, total soluble sugar, proline, relative water contents, and antioxidant-related gene expression via increasing reactive oxygen species (MDA, H2O2, O2•-) formation, resulting in plant growth reduction. The application of AsA and SeNPs, individually or in combination, decreased the uptake and translocation of Cr in rice seedlings, increased seedlings with tolerance to Cr toxicity, and significantly improved the rice seedling growth. Most notably, AsA + SeNP treatment strengthened the antioxidative defense system through ROS quenching and Cr detoxification. The results collectively suggested that the application of AsA and SeNPs alone or in combination had the potential to alleviate Cr toxicity in rice and possibly other crop species.

Advances in the Study of Selenium-Enriched Probiotics: From the Inorganic Se into Se Nanoparticles

Selenium (Se) is a momentous metallic element that plays an irreplaceable role in biochemical activities. Se deficiency remains a nutritional challenge across the world. Organic Se supplementation is the most effective treatment means for Se deficiency. Organic Se transformed from Se-enriched probiotics show outstanding excellent properties in antibacteria, anti-oxidation, anti-inflammation, and immunoregulation. Studying the influencing factors for Se enrichment capacity and enrichment mechanisms of Se-enriched probiotics is conducive to the exploit of more potent Se-enriched probiotics. Se-enriched probiotics transform inorganic Se into Se nanoparticles (SeNPs), which have been widely used in animal husbandry and biomedical field. In this paper, the novel development of Se-enriched probiotics is reviewed, and the bioactivities of SeNPs are assessed, so as to display their potential application prospects. The excellent role of SeNPs in anti-oxidation is summarized, and the mechanism by which SeNPs improve Se deficiency and boost animal health is explained.

Novel insights into the synergistic effects of selenium nanoparticles and metformin treatment of letrozole - induced polycystic ovarian syndrome: targeting PI3K/Akt signalling pathway, redox status and mitochondrial dysfunction in ovarian tissue

PURPOSE

Polycystic ovary syndrome (PCOS) has a series of reproductive and metabolic consequences. Although the link between PCOS, IR, and obesity, their impact on the pathogenesis of PCOS has yet to be determined. Dysfunction of PI3K/AKT pathway has been reported as the main cause of IR in PCOS. This study purposed to explore the effects of selenium nanoparticles (SeNPs) alone and combined with metformin (MET) in a PCOS-IR rat model.

METHODS

After 3 weeks of treatment with SeNPs and/or MET, biochemical analysis of glycemic & lipid profiles, and serum reproductive hormones was performed. Inflammatory, oxidative stress, and mitochondrial dysfunction markers were determined colormetrically. The expression of PI3K and Akt genes were evaluated by Real-time PCR. Histopathological examination and Immunohistochemical analysis of Ki-67 expression were performed.

RESULTS

The results showed that treatment with SeNPs and/or MET significantly attenuated insulin sensitivity, lipid profile, sex hormones levels, inflammatory, oxidative stress and mitochondrial functions markers. Additionally, PI3K and Akt genes expression were significantly upregulated with improved ovarian histopathological changes.

CONCLUSION

Combined SeNPs and MET therapy could be potential therapeutic agent for PCOS-IR model via modulation of the PI3K/Akt pathway, enhancing anti-inflammatory and anti-oxidant properties and altered mitochondrial functions.

HighlightsThe strong relationship between obesity, insulin resistance, and polycystic ovarian syndrome.Disturbance of the PI3K/Akt signaling pathway is involved in the progression of polycystic ovary syndrome-insulin resistance (PCOS-IR).In PCOS-IR rats, combined SeNPs and metformin therapy considerably alleviated IR by acting on the PI3K/Akt signaling pathway.The combination of SeNPs and metformin clearly repaired ovarian polycystic pathogenesis and improved hormonal imbalance in PCOS-IR rats.

Selenium nanoparticles improve fish sperm quality by enhancing glucose uptake capacity via AMPK activation

Appropriate additives can provide a suitable physiological environment for storage of fish sperm and facilitate the large-scale breeding of endangered species and commercial fish. Suitable additives for fish sperm storage in vitro are required for artificial insemination. This study evaluate the effects of 0.1, 0.5, 1.5, and 4.5 mg/L selenium nanoparticles (SeNPs) on the quality of Schizothorax prenanti and Onychostoma macrolepis sperm storage in vitro at 4 °C for 72 h. We found that 0.5 mg/L SeNPs was a suitable concentration for maintaining the normal physiological state of O. macrolepis sperm during storage at 4 °C (p < 0.05). Higher adenosine triphosphate (ATP) content of O. macrolepis sperm before and after activation was present at that concentration. To further explore the potential mechanism of action of SeNPs on O. macrolepis sperm, western blotting and glucose uptake analyses were performed. The results implied that after 24 h of in vitro preservation, 0.5 mg/L SeNPs significantly improved p-AMPK levels and glucose uptake capacity of O. macrolepis sperm, while compound C (CC), the inhibitor of activated AMP-activated protein kinase (p-AMPK), significantly restricted the function of SeNPs on stored sperm. Similar effects of 0.5 mg/L SeNPs were found on Schizothorax prenanti sperm. Our study demonstrates that SeNPs maintained ATP content and O. macrolepis and Schizothorax prenanti sperm function during storage in vitro for 72 h, possibly because SeNPs enhanced the glucose uptake capacity of sperm by maintaining the level of p-AMPK.

Selenium Nanoparticles Control H1N1 Virus by Inhibiting Inflammatory Response and Cell Apoptosis

The treatment of influenza caused by H1N1 has been the focus of much attention. Selenium nanoparticles (SeNPs) have been used in many aspects of research in the last two decades. They have shown excellent performance in antiviral, anti-inflammatory, and antioxidant functions. Previous anti-H1N1 cell experiments using SeNPs have shown that they have evident antiviral effects and low toxicities. This study focuses on the mechanism of selenium nanoparticles against an H1N1 influenza virus infection in vivo. The results showed that the selenium levels in the body decreased after an H1N1 virus infection, and inflammatory factors in the lung tissues increased abnormally, leading to the onset and aggravation of an inflammatory response. The H1N1 virus infection also led to the excessive activation of apoptotic pathways in the body and induced the apoptosis of tissue cells. In addition, this study found that SeNPs can alleviate this phenomenon. All results showed that SeNPs are promising inhibitors for controlling influenza H1N1 virus infections.

A Review of the Antibacterial, Fungicidal and Antiviral Properties of Selenium Nanoparticles

The resistance of microorganisms to antimicrobial drugs is an important problem worldwide. To solve this problem, active searches for antimicrobial components, approaches and therapies are being carried out. Selenium nanoparticles have high potential for antimicrobial activity. The relevance of their application is indisputable, which can be noted due to the significant increase in publications on the topic over the past decade. This review of research publications aims to provide the reader with up-to-date information on the antimicrobial properties of selenium nanoparticles, including susceptible microorganisms, the mechanisms of action of nanoparticles on bacteria and the effect of nanoparticle properties on their antimicrobial activity. This review describes the most complete information on the antiviral, antibacterial and antifungal effects of selenium nanoparticles.

Theranostic applications of selenium nanomedicines against lung cancer

The incidence and mortality rates of lung cancer are among the highest in the world. Traditional treatment methods include surgery, chemotherapy, and radiotherapy. Although rapid progress has been achieved in the past decade, treatment limitations remain. It is therefore imperative to identify safer and more effective therapeutic methods, and research is currently being conducted to identify more efficient and less harmful drugs. In recent years, the discovery of antitumor drugs based on the essential trace element selenium (Se) has provided good prospects for lung cancer treatments. In particular, compared to inorganic Se (Inorg-Se) and organic Se (Org-Se), Se nanomedicine (Se nanoparticles; SeNPs) shows much higher bioavailability and antioxidant activity and lower toxicity. SeNPs can also be used as a drug delivery carrier to better regulate protein and DNA biosynthesis and protein kinase C activity, thus playing a role in inhibiting cancer cell proliferation. SeNPs can also effectively activate antigen-presenting cells to stimulate cell immunity, exert regulatory effects on innate and regulatory immunity, and enhance lung cancer immunotherapy. This review summarizes the application of Se-based species and materials in lung cancer diagnosis, including fluorescence, MR, CT, photoacoustic imaging and other diagnostic methods, as well as treatments, including direct killing, radiosensitization, chemotherapeutic sensitization, photothermodynamics, and enhanced immunotherapy. In addition, the application prospects and challenges of Se-based drugs in lung cancer are examined, as well as their forecasted future clinical applications and sustainable development.

Evaluation of Selenium Nanoparticles in Inducing Disease Resistance against Spot Blotch Disease and Promoting Growth in Wheat under Biotic Stress

In the present study, SeNPs were synthesized using Melia azedarach leaf extracts and investigated for growth promotion in wheat under the biotic stress of spot blotch disease. The phytosynthesized SeNPs were characterized using UV-visible spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and Fourier-transformed infrared spectroscopy (FTIR). The in vitro efficacy of different concentrations of phytosynthesized SeNPs (i.e., 100 μg/mL, 150 μg/mL, 200 μg/mL, 250 μg/mL, and 300 μg/mL) was evaluated using the well diffusion method, which reported that 300 μg/mL showed maximum fungus growth inhibition. For in vivo study, different concentrations (10, 20, 30, and 40 mg/L) of SeNPs were applied exogenously to evaluate the morphological, physiological, and biochemical parameters under control conditions and determine when infection was induced. Among all treatments, 30 mg/L of SeNPs performed well and increased the plant height by 2.34% compared to the control and 30.7% more than fungus-inoculated wheat. Similarly, fresh plant weight and dry weight increased by 17.35% and 13.43% over the control and 20.34% and 52.48% over the fungus-treated wheat, respectively. In leaf surface area and root length, our findings were 50.11% and 10.37% higher than the control and 40% and 71% higher than diseased wheat, respectively. Plant physiological parameters i.e., chlorophyll a, chlorophyll b, and total chlorophyll content, were increased 14, 133, and 16.1 times over the control and 157, 253, and 42 times over the pathogen-inoculated wheat, respectively. Our findings regarding carotenoid content, relative water content, and the membrane stability index were 29-, 49-, and 81-fold higher than the control and 187-, 63-, and 48-fold higher than the negative control, respectively. In the case of plant biochemical parameters, proline, sugar, flavonoids, and phenolic contents were recorded at 6, 287, 11, and 34 times higher than the control and 32, 107, 33, and 4 times more than fungus-inoculated wheat, respectively. This study is considered the first biocompatible approach to evaluate the potential of green-synthesized SeNPs as growth-promoting substances in wheat under the spot blotch stress and effective management strategy to inhibit fungal growth.

Biogenic Selenium Nanoparticles in Biomedical Sciences: Properties, Current Trends, Novel Opportunities and Emerging Challenges in Theranostic Nanomedicine

Selenium is an important dietary supplement and an essential trace element incorporated into selenoproteins with growth-modulating properties and cytotoxic mechanisms of action. However, different compounds of selenium usually possess a narrow nutritional or therapeutic window with a low degree of absorption and delicate safety margins, depending on the dose and the chemical form in which they are provided to the organism. Hence, selenium nanoparticles (SeNPs) are emerging as a novel therapeutic and diagnostic platform with decreased toxicity and the capacity to enhance the biological properties of Se-based compounds. Consistent with the exciting possibilities offered by nanotechnology in the diagnosis, treatment, and prevention of diseases, SeNPs are useful tools in current biomedical research with exceptional benefits as potential therapeutics, with enhanced bioavailability, improved targeting, and effectiveness against oxidative stress and inflammation-mediated disorders. In view of the need for developing eco-friendly, inexpensive, simple, and high-throughput biomedical agents that can also ally with theranostic purposes and exhibit negligible side effects, biogenic SeNPs are receiving special attention. The present manuscript aims to be a reference in its kind by providing the readership with a thorough and comprehensive review that emphasizes the current, yet expanding, possibilities offered by biogenic SeNPs in the biomedical field and the promise they hold among selenium-derived products to, eventually, elicit future developments. First, the present review recalls the physiological importance of selenium as an oligo-element and introduces the unique biological, physicochemical, optoelectronic, and catalytic properties of Se nanomaterials. Then, it addresses the significance of nanosizing on pharmacological activity (pharmacokinetics and pharmacodynamics) and cellular interactions of SeNPs. Importantly, it discusses in detail the role of biosynthesized SeNPs as innovative theranostic agents for personalized nanomedicine-based therapies. Finally, this review explores the role of biogenic SeNPs in the ongoing context of the SARS-CoV-2 pandemic and presents key prospects in translational nanomedicine.

Antifungal Activity of Selenium Nanoparticles Obtained by Plant-Mediated Synthesis

The continuous need to satisfy world food demand has led to the search for new alternatives to combat economic losses in agriculture caused by phytopathogenic fungi. These organisms cause plant diseases, reducing their productivity and decreasing fruit quality. Among the new tools being explored is nanotechnology. Nanoparticles with antimicrobial properties could be an excellent alternative to address this problem. In this work, selenium nanoparticles (SeNPs) were obtained using plant extracts of Amphipterygium glaucum leaves (SeNPs-AGL) and Calendula officinalis flowers (SeNPs-COF). Characterization of the SeNPs was performed and their ability as antifungal agents against two commercially relevant plant pathogenic fungi, Fusarium oxysporum and Colletotrichum gloeosporioides, was evaluated. Assays were performed with different concentrations of SeNPs (0, 0.25, 0.5, 1.0, and 1.7 mg/mL). It was observed that both SeNPs had antifungal activity against both plant pathogens at concentrations of 0.25 mg/mL and above. SeNPs-AGL demonstrated better antifungal activity and smaller size (around 8.0 nm) than SeNPs-COF (134.0 nm). FTIR analysis evidenced the existence of different functional groups that constitute both types of SeNPs. There are factors that have to be considered in the antimicrobial activity of SeNPs such as nanoparticle size and phytochemical composition of the plant extracts used, as these may affect their bioavailability.

Greener microwave synthesized Se nanospheres for antioxidant, cell viability, and antibacterial effect

Selenium nanocrystals (SeNPs) were developed using Coccinia grandis fruit (CGF) extract by green microwave approach. The morphological characters revealed that the quasi SeNPs with dimensions ranging from 12 to 24 nm have been arranged in encapsulated spherical geometries with dimensions ranging from 0.47 to 0.71 m. The DPPH assay revealed that SeNPs at a concentration of 70 µl of 99.2% had the greatest possible scavenging capacity. The nanoparticle concentrations were around 500 g/mL and the cellular uptake of SeNPs through living thing extracellular matrix cell lines in vitro was limited to 75.1 ± 3.8%. The biocidal activity was tested against E. coli, B. cereus, and S. aureus strains. Since it had the greatest MIC against B. cereus with 32 mm compared with the reference antibiotics. These incredible qualities of SeNPs suggest that attempting to manipulate multi-purpose nanoparticles for powerful and flexible wound and skin therapeutic innovations is very impressive.

Graphical abstract

Glutathione and selenium nanoparticles have a synergistic protective effect during cryopreservation of bull semen

Introduction

In the present study, the synergistic protective effect of co-supplementation of glutathione (GSH) with selenium nanoparticles (SeNPs) on the cryopreservation efficiency of bull semen was analyzed.

Methods

After collection, the ejaculates of Holstein bulls were subsequently diluted with a Tris extender buffer supplemented with different concentrations of SeNPs (0, 1, 2, and 4 μg/ml), followed by semen equilibration at 4°C and assessment of sperm viability and motility. Subsequently, the ejaculates of Holstein bulls were pooled, split into four equal groups, and diluted with a Tris extender buffer supplemented with basic extender (negative control group, NC group), 2 μg/ml SeNPs (SeNPs group), 4 mM GSH (GSH group), and 4 mM GSH plus 2 μg/ml SeNPs (GSH + SeNPs group). After cryopreservation, motility, viability, mitochondrial activity, plasma membrane integrity, acrosome integrity, concentration of malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT), and ability of frozen-thawed sperm cells to support in vitro embryonic development were evaluated.

Results and discussion

No side effect of SeNPs concentrations applied in the current study on the motility and viability of equilibrated bull spermatozoa was found. Meanwhile, supplementation of SeNPs significantly promoted the motility and viability of equilibrated bull spermatozoa. Furthermore, the co-supplementation of GSH with SeNPs effectively protected bull spermatozoa from cryoinjury as expressed by promoting semen motility, viability, mitochondrial activity, plasma membrane integrity, and acrosome integrity. Finally, the enhanced antioxidant capacity and embryonic development potential in the frozen-thawed bull spermatozoa cryopreserved by co-supplementation of GSH with SeNPs further confirmed the synergistic protective effect of co-supplementation of GSH with SeNPs on the cryopreservation of bull semen.

Selenium Nanoparticles Synergistically Stabilized by Starch Microgel and EGCG: Synthesis, Characterization, and Bioactivity

Selenium (Se) is a chemical element essential to human health because of its bioactive properties, including antioxidative, anticancer, and immunomodulating activities. Despite the high therapeutic potential of Se, its intrinsic properties of poor stability, a narrow therapeutic window, and low bioavailability and bioactivity have limited its clinical applications. Selenium nanoparticles (SeNPs) exhibit lower toxicity and higher bioactivity than other Se forms. Herein, we report a green method for the preparation of monodisperse SeNPs with starch microgel (SM) and epigallocatechin gallate (EGCG) through Se-O bonds and polysaccharide-polyphenol interactions (namely, SM-EGCG-SeNPs). SM-EGCG-SeNPs showed higher stability, bioactivities, and cytotoxicity than SeNPs and SM-SeNPs at the equivalent dose. SM-EGCG-SeNPs induced the apoptosis of cancer cells via the activation of several caspases and reactive oxygen species overproduction. This work proposes a facile method for the design and potentiation of structure-bioactive SeNPs via polysaccharide-polyphenol interactions.

Selenium Nanoparticles Can Influence the Immune Response Due to Interactions with Antibodies and Modulation of the Physiological State of Granulocytes

Currently, selenium nanoparticles (SeNPs) are considered potential immunomodulatory agents and as targets for activity modulation are granulocytes, which have the most abundant population of immune blood cells. The present study aims to evaluate the cytotoxic effect and its effect on the functional responses of granulocytes. In addition to the intrinsic activity of SeNPs, we studied the activity of the combination of SeNPs and IgG antibodies. Using laser ablation and fragmentation, we obtained nanoparticles with an average size of 100 nm and a rather narrow size evolution. The resulting nanoparticles do not show acute toxicity to primary cultures of fibroblasts and hepatocytes, epithelial-like cell line L-929 and granulocyte-like culture of HL-60 at a concentration of 10⁹ NPs/mL. SeNPs at a concentration of 10¹⁰ NPs/mL reduced the viability of HL-60 cells by no more than 10% and did not affect the viability of the primary culture of mouse granulocytes, and did not have a genotoxic effect on progenitor cells. The addition of SeNPs can affect the production of reactive oxygen species (ROS) by mouse bone marrow granulocytes, modulate the proportion of granulocytes with calcium spikes and enhance fMLF-induced granulocytes degranulation. SeNPs can modulate the effect of IgG on the physiological responses of granulocytes. We studied the expression level of genes associated with inflammation and cell stress. SeNPs increase the expression of catalase, NF-κB, Xrcc5 and some others; antibodies enhance the effect of SeNPs, but IgG without SeNPs decreases the expression level of these genes. This fact can be explained by the interaction between SeNPs and IgG. It has been established that antibodies interact with SeNPs. We showed that antibodies bind to the surface of selenium nanoparticles and are present in aqueous solutions in a bound form from DLS methods, ultraviolet-visible spectroscopy, vibrational-rotational spectrometry, fluorescence spectrometry, and refractometry. At the same time, in a significant part of the antibodies, a partial change in the tertiary and secondary structure is observed. The data obtained will allow a better understanding of the principles of the interaction of immune cells with antibodies and SeNPs and, in the future, may serve to create a new generation of immunomodulators.

Biogenic Selenium Nanoparticles Synthesized by Lactobacillus casei ATCC 393 Alleviate Acute Hypobaric Hypoxia-Induced Intestinal Barrier Dysfunction in C57BL/6 Mice

Exposure to hypobaric hypoxia at high altitude will cause different tissue and organ damage over a long period of time. Studies have shown that hypobaric hypoxia can cause severe primary intestinal barrier dysfunction, and then cause multiple organ dysfunction. Our previous research showed that selenium nanoparticles (SeNPs) synthesized by Lactobacillus casei ATCC 393 (L. casei ATCC 393) can effectively alleviate intestinal barrier dysfunction caused by oxidative stress and inflammation in mice. This study was conducted to investigate the protective effect of biological SeNPs synthesized by L. casei ATCC 393 on intestinal barrier function in acute hypobaric hypoxic stress mice. The results showed that compared with the hypobaric hypoxic, the SeNPs synthesized by L. casei ATCC 393 by oral administration could effectively alleviate the shortening of intestinal villi, which decreased the level of diamine oxidase (DAO) and myeloperoxidase (MPO), and the expression level of tight junction protein in ileum was increased. In addition, SeNPs significantly increased the activities of superoxide dismutase (SOD), cyclooxygenase (COX-1) and glutathione peroxidase (GPx), and decreased the level of malondialdehyde (MDA), and inhibit the increase of hypoxia related factor. SeNPs effectively regulate the intestinal microecology disorder caused by hypobaric hypoxia stress, and maintain the intestinal microecology balance. In addition, oral administration of SeNPs had better protective effect on intestinal barrier function of mice under hypobaric hypoxia stress. These results suggested that SeNPs synthesized by L. casei ATCC 393 can effectively alleviate the damage of intestinal barrier function under acute hypobaric hypoxic stress, which may be closely related to the antioxidant activity of SeNPs.

Effect of Phytosynthesized Selenium and Cerium Oxide Nanoparticles on Wheat (Triticum aestivum L.) against Stripe Rust Disease

In this study, selenium nanoparticles (SeNPs) and cerium oxide nanoparticles (CeONPs) were synthesized by using the extract of Melia azedarach leaves, and Acorus calamusas rhizomes, respectively, and investigated for the biological and sustainable control of yellow, or stripe rust, disease in wheat. The green synthesized NPs were characterized by UV-Visible spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and X-ray diffraction (XRD). The SeNPs and CeONPs, with different concentrations (i.e., 10, 20, 30, and 40 mg/L), were exogenously applied to wheat infected with Puccinia striformis. SeNPs and CeONPs, at a concentration of 30 mg/L, were found to be the most suitable concentrations, which reduced the disease severity and enhanced the morphological (plant height, root length, shoot length, leaf length, and ear length), physiological (chlorophyll and membrane stability index), biochemical (proline, phenolics and flavonoids) and antioxidant (SOD and POD) parameters. The antioxidant activity of SeNPs and CeONPs was also measured. For this purpose, different concentrations (50, 100, 150, 200 and 400 ppm) of both SeNPs and CeONPs were used. The concentration of 400 ppm most promoted the DPPH, ABTS and reducing power activity of both SeNPs and CeONPs. This study is considered the first biocompatible approach to evaluate the potential of green synthesized SeNPs and CeONPs to improve the health of yellow, or stripe rust, infected wheat plants and to provide an effective management strategy to inhibit the growth of Puccinia striformis.

Antioxidant and anti-apoptotic effects of selenium nanoparticles and Lactobacillus casei on mice testis after X-ray

Radiation can lead to various damages in the process of spermatogenesis that lead to a decrease in the number of sperm, an increase in spermatogenesis disorders, and defective sperm function. Radioprotectors are considered a good approach to reducing the damage caused by radiation. The goal of this work was to study how X-ray radiation affects testicular tissue and the process of spermatogenesis, as well as the radioprotective effects of selenium nanoparticles (SeNPs) and Lactobacillus casei (L. casei) as probiotic compounds, given alone or together. This study included 64 adult Syrian male mice weighing approximately 20 ± 5 g and aged 10 ± 1 weeks. Animals were randomly divided into eight groups: control group, SeNPs, probiotic, SeNPs and probiotic, X-ray radiation, SeNPs (X-ray), probiotic (X-ray), and SeNPs and probiotic (X-ray). Histology parameters and levels of oxidative stress biomarkers such as catalase, malondialdehyde, superoxide dismutase, and glutathione peroxidase were examined. In addition, the level of apoptosis was measured in testicular cells that had been treated with SeNPs and L. casei as a probiotic. The results showed that the administration of SeNPs or probiotic diminished the effects of X-ray radiation. These compounds induced a significant decreased in malondialdehyde, caspase 3, and caspase 9 gene levels and a remarkable increased in catalase, superoxide dismutase, and Catsper gene expression. SeNPs and probiotic exhibited a potent antioxidant effect and elevated the mean number of spermatogonia cells, sperm cell count, spermatogenesis percentage, and sperm motility percentage. The prescribed compound exhibited an ideal radioprotective effect with the ability to reduce the side effects of ionizing radiation and to protect normal tissues. SeNPs and probiotic inhibit testicular injury and improve the antioxidant state in male mice.

Biogenic synthesis of selenium and tellurium nanoparticles by marine bacteria and their biological activity

Selenium (SeNPs) and tellurium nanoparticles (TeNPs) were synthesized by green technology using the three new bacterial marine isolates (strains PL 2476, AF 2469 and G 2451). Isolates were classified as Pseudoalteromonas shioyasakiensis according to 16S rRNA sequence analysis, morphological characteristics, and biochemical reactions. The bioreduction processes of isolates were studied in comparison with the previously described Alteromonas macleodii (strain 2328). All strains exhibited significant tolerance to selenite and tellurite up to 1000 µg/mL. A comparative analysis of the bioreduction processes of the isolates demonstrated that the strains have a high rate of reduction processes. Characterization of biogenic red SeNPs and black TeNPs using scanning electron microscopy (SEM), EDX analysis, Dynamic Light Scattering, and micro-Raman Spectroscopy revealed that all the isolates form stable spherical selenium and tellurium nanoparticles whose size as well as elemental composition depend on the producer strain. Nanoparticles of the smallest size (up to 100 nm) were observed only for strain PL 2476. Biogenic SeNPs and TeNPs were also characterized and tested for their antimicrobial, antifouling and cytotoxic activities. Significant antimicrobial activity was shown for nanoparticles at relatively high concentrations (500 and 1000 µg/mL), with the antimicrobial activity of TeNPs being more significant than SeNPs. In contrast, against cell cultures (breast cancer cells (SkBr3) and human dermal fibroblasts (HDF) SeNPs showed greater toxicity than tellurium nanoparticles. Studies have demonstrated the high antifouling effectiveness of selenium and tellurium nanoparticles when introduced into self-polishing coatings. According to the results obtained, the use of SeNPs and TeNPs as antifouling additives can reduce the concentration of leachable biocides used in coatings, reducing the pressure on the environment.

Innovating the Synergistic Assets of β-Amino Butyric Acid (BABA) and Selenium Nanoparticles (SeNPs) in Improving the Growth, Nitrogen Metabolism, Biological Activities, and Nutritive Value of Medicago interexta Sprouts

In view of the wide traditional uses of legume sprouts, several strategies have been approved to improve their growth, bioactivity, and nutritive values. In this regard, the present study aimed at investigating how priming with selenium nanoparticles (SeNPs, 25 mg L^-1) enhanced the effects of β-amino butyric acid (BABA, 30 mM) on the growth, physiology, nitrogen metabolism, and bioactive metabolites of Medicago interexta sprouts. The results have shown that the growth and photosynthesis of M. interexta sprouts were enhanced by the treatment with BABA or SeNPs, being higher under combined treatment. Increased photosynthesis provided the precursors for the biosynthesis of primary and secondary metabolites. In this regard, the combined treatment had a more pronounced effect on the bioactive primary metabolites (essential amino acids), secondary metabolites (phenolics, GSH, and ASC), and mineral profiles of the investigated sprouts than that of sole treatments. Increased amino acids were accompanied by increased nitrogen metabolism, i.e., nitrate reductase, glutamate dehydrogenase (GDH), glutamate synthase (GOGAT), glutamine synthase (GS), cysteine synthesis serine acetyltransferase, arginase, threonine synthase, and methionine synthase. Further, the antioxidant capacity (FRAP), the anti-diabetic activities (i.e., α-amylase and α-glucosidase inhibition activities), and the glycemic index of the tested sprouts were more significantly improved by the combined treatment with BABA and SeNPs than by individual treatment. Overall, the combined effect of BABA and SeNPs could be preferable to their individual effects on plant growth and bioactive metabolites.

Selenium nanoparticles reduced cadmium uptake, regulated nutritional homeostasis and antioxidative system in Coriandrum sativum grown in cadmium toxic conditions

Nanotechnology has become a valuable novel approach to manage several environmental challenges through providing innovative and effective solutions. Heavy metal stress is an important abiotic limiting factor. Seed priming with selenium (Se) alleviates various kinds of environmental stresses; yet, the potential of seed priming with selenium nanoparticles (SeNPs) under cadmium (Cd) stress for coriander crop has never been evaluated. This research work was designed to explore the effects of seed priming with three levels (0, 5, 10 and 15 mg L^-1) of SeNPs solution on the physio-biochemical characteristics, nutrition, antioxidative defense system and growth of coriander under Cd stress. Cadmium toxicity reduced chlorophyll content, photosynthetic activity and growth of treated plants. Moreover, Cd stressed plants exhibited modulations in proline level, together with decreased water potential, and leaf osmotic potential. However, SeNPs increased growth attributes, chlorophyll content, total soluble sugars, leaf relative water content, and gas exchange parameters in treated plants which were conversely decreased by Cd toxicity. The seeds priming with SeNPs promoted antioxidant response by increasing catalase (CAT), ascorbate peroxidase (APX) and peroxidase (POX) activity and safeguarding cellular structures through scavenging free radicals and reactive oxygen species. Furthermore, Cd stressed plants displayed an upper level of MDA (1.91 fold) while SeNPs improved membranous integrity through detoxification of hydrogen peroxide. Additionally, SeNPs enhanced nutrients contents (P, K, Ca, Mg, Zn), metal tolerance index and diminished Cd content in plants resulting in the improved growth and development of Cd affected coriander plants.

Selenium and zinc oxide nanoparticles modulate the molecular and morpho-physiological processes during seed germination of Brassica napus under salt stress

The advent of the nanotechnology era offers a unique opportunity for sustainable agriculture, and the contribution of nanoparticles (NPs) to ameliorate abiotic stresses became the new area of interest for researchers due to their special physiochemical characteristics in the biological system. Salinity is a key devastating abiotic factor that hinders the development and yield of rapeseed. On the flip side, the impact of nanoparticles on plant hormones upon salt stress during seed imbibition and germination has been poorly understood. Hence, we aimed to study the influence of nanopriming on plant hormones and germination processes using selenium and zinc oxide nanoparticles (SeNPs and ZnONPs) during seed imbibition and the early seedling stage upon salinity stress. Nanopriming showed a positive effect on final germination percentage, germination rate, seed microstructure, and antioxidant enzyme activity of two rapeseed cultivars under salt stress. Moreover, nano-treatment decreased the expression of abscisic acid related genes BnCYP707A1, 3, and 4 during the priming time and after sowing, where the levels of BnCYP707A1, and 3 genes showed a slightly significant difference between the nanopriming and hydropriming, which gave an evidence that the nanopriming influenced the ABA levels then elevated the seed germination with SeNPs and ZnONPs. Likewise, nanoparticles significantly elevated the expression levels of BnGA20ox, BnGA3ox and BnCPS genes during the germination stage, especially at 24 h after being sown in salt stress. That confirms the positive role of SeNPs and ZnONPs in regulating gibberellic acid level, which increases the germination in primed seeds as compared to unprimed seeds and hydroprimed seeds. Additionally, our results demonstrated that nanopriming regulated the expression level of BnCAM and BnPER during priming time and after sowing, along with the various levels of expression remarkably in BnEXP4 and BnRAB28, especially at 24 h of being sown under salt stress, which promoted seed germination and early seedling growth. Overall, this work provides new insights into mechanisms underlying the interactions of SeNPs and ZnONPs with plant hormones during the seed imbibition and early seedling stage, consequently enhanced plant growth and development. Additionally, these findings portrayed that the application of SeNPs and ZnONPs could be a new strategy and useful approach to enhance tolerance against salinity in rapeseed plants.

Trace Element Selenium Effectively Alleviates Intestinal Diseases

Selenium (Se) is an essential trace element in the body. It is mainly used in the body in the form of selenoproteins and has a variety of biological functions. Intestinal diseases caused by chronic inflammation are among the most important threats to human health, and there is no complete cure at present. Due to its excellent antioxidant function, Se has been proven to be effective in alleviating intestinal diseases such as inflammatory bowel diseases (IBDs). Therefore, this paper introduces the role of Se and selenoproteins in the intestinal tract and the mechanism of their involvement in the mediation of intestinal diseases. In addition, it introduces the advantages and disadvantages of nano-Se as a new Se preparation and traditional Se supplement in the prevention and treatment of intestinal diseases, so as to provide a reference for the further exploration of the interaction between selenium and intestinal health.

Biogenic synthesis and characterization of selenium nanoparticles and their applications with special reference to antibacterial, antioxidant, anticancer and photocatalytic activity

Oxyanions of selenium, selenite (SeO₃)^2- and selenate (SeO₄)^2- are toxic to terrestrial and aquatic biota but few microorganisms including cyanobacteria are resistant to high levels of selenite. Cyanobacteria evade selenite toxicity through bioreduction and synthesis of selenium nanoparticles (SeNPs). In this study, extracellular biosynthesis of SeNPs (Se⁰) using cyanobacterium, Anabaena sp. PCC 7120 on exposure to sodium selenite and characterization was done by using UV-visible spectroscopy, SEM-EDX, TEM and FTIR analyses which confirmed spherical shape with size range of 5-50 nm diameter. These biogenic SeNPs demonstrated significant antibacterial and anti-biofilm activity against bacterial pathogens. Furthermore, these SeNPs showed high antioxidant activity at minimum concentration of 50 µg/mL and significant anti-proliferative activity against HeLa cell line with IC₅₀ value of 5.5 µg/mL. The SeNPs also induced accumulation of cancer cells in the sub-G1 phase which was clearly observed in cellular and nuclear morphology. These biofabricated SeNPs also reduced and decolorized toxic methylene blue dye significantly through photocatalytic degradation. Therefore Anabaena sp. PCC 7120 may be employed as a green bioresource to synthesize SeNPs with potential applications in medicine and environmental bioremediation.

Biosynthesis of Selenium Nanoparticles (via Bacillus subtilis BSN313), and Their Isolation, Characterization, and Bioactivities

Among the trace elements, selenium (Se) has great demand as a health supplement. Compared to its other forms, selenium nanoparticles have minor toxicity, superior reactivity, and excellent bioavailability. The present study was conducted to produce selenium nanoparticles (SeNPs) via a biosynthetic approach using probiotic Bacillus subtilis BSN313 in an economical and easy manner. The BSN313 exhibited a gradual increase in Se reduction and production of SeNPs up to 5–200 µg/mL of its environmental Se. However, the capability was decreased beyond that concentration. The capacity for extracellular SeNP production was evidenced by the emergence of red color, then confirmed by a microscopic approach. Produced SeNPs were purified, freeze-dried, and subsequently characterized systematically using UV–Vis spectroscopy, FTIR, Zetasizer, SEM–EDS, and TEM techniques. SEM–EDS analysis proved the presence of selenium as the foremost constituent of SeNPs. With an average particle size of 530 nm, SeNPs were shown to have a −26.9 (mV) zeta potential and −2.11 µm cm/Vs electrophoretic mobility in water. SeNPs produced during both the 24 and 48 h incubation periods showed good antioxidant activity in terms of DPPH and ABST scavenging action at a concentration of 150 µg/mL with no significant differences (p > 0.05). Moreover, 200 µg/mL of SeNPs showed antibacterial reactivity against Escherichia coli ATCC 8739, Staphylococcus aureus ATCC 9027, and Pseudomonas aeruginosa ATCC 25923. In the future, this work will be helpful to produce biogenic SeNPs using probiotic Bacillus subtilis BSN313 as biofactories, with the potential for safe use in biomedical and nutritional applications.

Selenium nanoparticles ameliorate Brassica napus L. cadmium toxicity by inhibiting the respiratory burst and scavenging reactive oxygen species

Cadmium (Cd) is a widely distributed soil contaminant which induces oxidative damage and is therefore toxic to plants. Although selenium oxyanions such as selenite (SeO₃^2-) and selenate (SeO₄^2-) can alleviate Cd stress to plants, it is not known whether selenium nanoparticles (SeNPs) are able to do the same. The present study demonstrated the positive impact of both SeNPs and SeO₃^2- on Brassica napus L. growth under conditions of Cd stress. Underlying mechanisms were elucidated using an oxidative stress detection assay, whole-genome RNA sequencing, and RT-qPCR. Application of selenium, especially in the form of SeNPs, decreased Cd-induced reactive oxygen species production by inhibiting the expression of NADPH oxidases (BnaRBOHC, BnaRBOHD1, and BnaRBOHF1) and glycolate oxidase (BnaGLO), thereby decreasing oxidative protein and membrane lipid damage. In addition, SeNPs improved resistance to Cd stress by decreasing Cd accumulation, maintaining intracellular calcium homeostasis, promoting disulfide bond formation, and restoring the waxy outer layer of the leaf surface. Although both forms of selenium decreased Cd toxicity, the beneficial concentration range was more extensive for SeNPs than for SeO₃^2-.

Two new selenite reducing bacterial isolates from paddy soil and the potential Se biofortification of paddy rice

Selenium (Se) is an essential element for human health. Se-enriched agricultural products can promote people's intake of Se. Microorganisms play an important role in Se cycling. In this study, two new bacterial strains were isolated from paddy soil and were identified as Chitinophaga sp. and Comamonas testosteroni, respectively. More than 44% and 39% of 1.0 mM selenite were reduced in 84 h by them using yeast extract as carbon source, respectively. Scanning electron microscope (SEM) and Energy dispersive X-ray spectrometry (EDS) results indicated that the reduction product of selenite was nanometer Se. These strains could promote the available Se in soil and the content of Se in rice plants in pot experiments. Organic combined Se in soils was increased up to 35%, accompanied by the 92% and 130% increase of Se in rice plants. To our best knowledge, this is the first report of Se reduction by Chitinophaga. This work might provide a prospective strategy for microbial fortification of Se in corps.

Administration of Selenium Nanoparticles Reverses Streptozotocin-Induced Neurotoxicity in the male rats

Alzheimer's disease is the most common neurodegenerative disease associated with deposition of amyloid-beta and the increased oxidative stress. High free radical scavenging ability of selenium nanoparticles (SeNPs) has been acknowledged, so in the present study, the effects of treatment with SeNPs on Streptozotocin (STZ)-induced neurotoxicity were evaluated in the male rats. Learning and memory impairment was induced by intraventricular injection of STZ. Following induction of memory impairment, the rats received 0.4 mg/kg of SeNPs daily for one month. Memory function, antioxidant capacity, and deposition of Amyloid β (Aβ) were assessed using the shuttle box task, biochemical methods, and Congo red staining. Injection of STZ caused memory impairment, a decrease in the level of total thiol group (TTG), and an increase in the malondialdehyde (MDA) content and deposition of Aβ. Administration of SeNPs reversed the neurotoxicity induced by STZ. It seems that SeNPs likely had neuroprotective effects on the animal model of Alzheimer's disease through increasing antioxidants҆ capacity.

Green Synthesis of Selenium and Tellurium Nanoparticles: Current Trends, Biological Properties and Biomedical Applications

The synthesis and assembly of nanoparticles using green technology has been an excellent option in nanotechnology because they are easy to implement, cost-efficient, eco-friendly, risk-free, and amenable to scaling up. They also do not require sophisticated equipment nor well-trained professionals. Bionanotechnology involves various biological systems as suitable nanofactories, including biomolecules, bacteria, fungi, yeasts, and plants. Biologically inspired nanomaterial fabrication approaches have shown great potential to interconnect microbial or plant extract biotechnology and nanotechnology. The present article extensively reviews the eco-friendly production of metalloid nanoparticles, namely made of selenium (SeNPs) and tellurium (TeNPs), using various microorganisms, such as bacteria and fungi, and plants' extracts. It also discusses the methodologies followed by materials scientists and highlights the impact of the experimental sets on the outcomes and shed light on the underlying mechanisms. Moreover, it features the unique properties displayed by these biogenic nanoparticles for a large range of emerging applications in medicine, agriculture, bioengineering, and bioremediation.

Biomedical Potential of Plant-Based Selenium Nanoparticles: A Comprehensive Review on Therapeutic and Mechanistic Aspects

Selenium nanoparticles (SeNPs) have advantages over other nanomaterials because of the promising role of selenium in the stabilization of the immune system and activation of the defense response. The use of SeNPs and their supplements not only have pharmacological significance but also boost and prepare the body's immune system to fight the pathogens. This review summarizes the recent progress in the biogenesis of plant-based SeNPs by using various plant species and the role of secondary metabolites on their biocompatible functioning. Phyto-synthesis of SeNPs results in the synthesis of nanomaterials of various, size, shape and biochemical nature and has advantages over other routine physical and chemical methods because of their biocompatibility, eco-friendly nature and in vivo actions. Unfortunately, the plant-based SeNPs failed to attain considerable attention in the pharmaceutical industry. However, a few studies were performed to explore the therapeutic potential of the SeNPs against various cancer cells, microbial pathogens, viral infections, hepatoprotective actions, diabetic management, and antioxidant approaches. Further, some of the selenium-based drug delivery systems are developed by engineering the SeNPs with the functional ligands to deliver drugs to the targeted sites. This review also provides up-to-date information on the mechanistic actions that the SeNPs adopt to achieve their designated tasks as it may help to develop precision medicine with customized treatment and healthcare for the ailing population.

A newly isolated Bacillus amyloliquefaciens SRB04 for the synthesis of selenium nanoparticles with potential antibacterial properties

The aim of this study was to isolate and characterize marine bacterial strains capable of converting selenite to elemental selenium with the formation of Se nanoparticles (SeNPs). For the first time, a novel marine strain belonging to Bacillus amyloliquefaciens (GenBank accession no. MK392020) was isolated from the coast of the Caspian Sea and characterized based on its ability for transformation of selenite to SeNPs under aerobic conditions. The preliminary formation of SeNPs was confirmed via color changes and the products characterized by UV-Vis spectroscopy. The field-emission scanning electron microscopy (FESEM) together with energy-dispersive X-ray (EDX) analysis showed the presence of the spherical SeNPs on both the surface of the bacterial biomass and in the supernatant solution. Dynamic light scattering (DLS) analysis showed the SeNPs to have an average particle size (Z-average) around 45.4-68.3 nm. The X-ray diffraction (XRD) studies substantiated the amorphous nature of the biosynthesized SeNPs. Fourier-transform infrared spectroscopic (FTIR) studies of the SeNPs indicated typical proteinaceous and lipid-related bands as capping agents on the SeNPs. Different effective parameters corresponding the yield of SeNPs by B. amyloliquefaciens strain SRB04 were optimized under resting cell strategy. Results showed that the optimal process conditions for SeNP production were 2 mM of selenite oxyanion, 20 g/L of cell biomass, and 60 h reaction time. The synthesized SeNPs had a remarkable antibacterial activity on Staphylococcus aureus compared with chloramphenicol as a broad-spectrum antibiotic.

A comparative study on the accumulation, translocation and transformation of selenite, selenate, and SeNPs in a hydroponic-plant system

Plants can play important roles in overcoming selenium (Se) deficiency and Se toxicity in various regions of the world. Selenite (SeIV), selenate (SeVI), as well as Se nanoparticles (SeNPs) naturally formed through reduction of SeIV, are the three main Se species in the environment. The bioaccumulation and transformation of these Se species in plants still need more understanding. The aims of this study are to investigate the phytotoxicity, accumulation, and transformation of SeIV, SeVI and SeNPs in garlic, a relatively Se accumulative plant. The spatial distribution of Se in the roots were imaged using synchrotron radiation micro-focused X-ray fluorescence (SR-μXRF). The chemical forms of Se in different plant tissues were analyzed using synchrotron radiation X-ray absorption spectroscopy (SR-XAS). The results demonstrate that 1) SeNPs which has the lowest phytotoxicity is stable in water, but prone to be converted to organic Se species, such as C-Se-C (MeSeCys) upon uptake by root. 2) SeIV is prone to concentrate in the root and incorporated into C-Se-C (MeSeCys) and C-Se-R (SeCys) bonding forms; 3) SeVI with the lowest transformation probability to organic Se species has the highest phytotoxicity to plant, and is much easier to translocate from root to leaf than SeNPs and SeIV. The present work provides insights into potential impact of SeNPs, selenite and selenate on aquatic-plant ecosystems, and is beneficial for systematically understanding the Se accumulation and transformation in food chain.

Selenium nanoparticles induce autophagy mediated cell death in human keratinocytes

Aim: Selenium nanoparticles (SeNPs) may have a potential role in treating dermal disorders due to its wide therapeutic properties, but there is a need to evaluate its toxicity in keratinocytes. The present study evaluated the molecular mechanism and mode of cell death induced by SeNPs on dermal keratinocytes. Materials & methods: SeNPs were synthesized, characterized and studied in human keratinocytes cells. Oxidative stress and mitochondrial membrane depolarization were evaluated by various techniques. Additionally, autophagy mediated apoptotic cell death was evaluated. Results: SeNPs induced oxidative stress and apoptotic cell death in keratinocytes by increasing autophagy through the formation of acidic lysosomes and autophagosomes. Conclusion: Overall, SeNPs induce the oxidative stress and autophagy mediated apoptotic cell death in human keratinocytes cells.

Novel mechanisms of selenate and selenite reduction in the obligate aerobic bacterium Comamonas testosteroni S44

Selenium oxyanion reduction is an effective detoxification or/and assimilation processes in organisms, but little is known the mechanisms in aerobic bacteria. Aerobic Comamonas testosteroni S44 reduces Se(VI)/Se(IV) to less-toxic elemental selenium nanoparticles (SeNPs). For Se(VI) reduction, sulfate and Se(VI) reduction displayed a competitive relationship. When essential sulfate reducing genes were respectively disrupted, Se(VI) was not reduced to red-colored SeNPs. Consequently, Se(VI) reduction was catalyzed by enzymes of the sulfate reducing pathway. For Se(IV) reduction, one of the potential periplasm molybdenum oxidoreductase named SerT was screened and further used to analyze Se(IV) reduction. Compared to the wild type and the complemented mutant strain, the ability of Se(IV) reduction was reduced 75% in the deletion mutant ΔserT. Moreover, the Se(IV) reduction rate was significantly enhanced when the gene serT was overexpressed in Escherichia coli W3110. In addition, Se(IV) was reduced to SeNPs by the purified SerT with the presence of NADPH as the electron donor in vitro, showing a V_max of 61 nmol/min·mg and a K_m of 180 μmol/L. A model of Se(VI)/Se(IV) reduction was generated in aerobic C. testosteroni S44. This work provides new insights into the molecular mechanisms of Se(VI)/Se(IV) reduction activities in aerobic bacteria.

Discrete SeNPs-Macromolecule Binding Manipulated by Hydrophilic Interaction

Nanoparticle-protein conjugates are promising probes for biological diagnostics and versatile building blocks for nanotechnology. Here we demonstrate the interaction of SeNPs with BSA macromolecule simply by physical adsorption method. The interaction between SeNPs and BSA has been investigated by UV-Vis, fluorescence, circular dichroism (CD) spectroscopic and thermal methods. The esterase-like activity of BSA towards PNPA was investigated in the presence of SeNPs. The effects of SeNPs on the stability and conformational changes of BSA were studied, which indicated that the binding of SeNPs with BSA induced relative changes in secondary structure of protein. SeNPs acted as a structure stabilizer for BSA which was further confirmed by thermal denaturation study. The hydrophilic bonding forces played important roles in the BSA-SeNPs complex formation. The putative binding site of SeNPs on BSA was near to Sudlow's site II. The hydrophilic interaction of SeNPs on the stability and structure of BSA would find promising application in drug delivery system.

Sodium selenite/selenium nanoparticles (SeNPs) protect cardiomyoblasts and zebrafish embryos against ethanol induced oxidative stress

Alcoholic cardiomyopathy is the damage caused to the heart muscles due to high level of alcohol consumption resulting in enlargement and inflammation of the heart. Selenium is an important trace element that is beneficial to human health. Selenium protects the cells by preventing the formation of free radicals in the body. In the present study, protein mediated synthesis of SeNPs was investigated. Two different sizes of SeNPs were synthesized using BSA and keratin. The synthesized SeNPs were characterized by scanning electron microscopy (SEM) with elemental composition analysis Energy Dispersive X-ray spectroscopy(EDX) and X-ray diffraction (XRD). This study demonstrates the in vitro and in vivo antioxidative effects of sodium selenite and SeNPs. Further selenium and SeNPs were evaluated for their ability to protect against 1% ethanol induced oxidative stress in H9C2 cell line. The selenium and SeNPs were found to reduce the 1% ethanol-induced oxidative damage through scavenging intracellular reactive oxygen species. The selenium and SeNPs could also prevent pericardial edema induced ethanol treatment and reduced apoptosis and cell death in zebrafish embryos. The results indicate that selenium and SeNPs could potentially be used as an additive in alcoholic beverage industry to control the cardiomyopathy.

Th1 Immune Response Induction by Biogenic Selenium Nanoparticles in Mice with Breast Cancer: Preliminary Vaccine Model

BACKGROUND

Tumor associated antigens can be viably used to enhance host immune response.

OBJECTIVES

The immunomodulatory effect of biogenic selenium nanoparticles (SeNPs) was compared between treated and untreated mice with crude antigens of 4T1 cells.

MATERIALS AND METHODS

Female inbred BALB/c mice (60) were injected by cancinogenic 4T1 cells causing breast cancer. After 10 days, all tumor bearing mice were divided into 4 groups. Group 1 was daily provided oral PBS and injected by the same buffer after tumor induction and was considered as control. Group 2 received only 100 μg/day SeNPs as an oral supplement for 30 days. Group 3 was only injected with 4T1 cells crude antigens with nil supplementation of SeNPs. Group 4 animals were supplemented 100 μg/day SeNPs for 30 days and simultaneously injected with crude antigens of 4T1 cells. All antigens or PBS injections were introduced at 7, 14 and 28 days following tumor induction. Oral PBS and SeNPs supplementation initiated from the first day of tumor induction and continued up to 30 days. During tumor growth, animal weights and survival rates were monitored and at the end of the study the concentrations of different cytokines and DTH responses were measured.

RESULTS

Data clearly showed that the levels of cellular immunomodulatory components (granzyme B, IL-12, IFN-γ, and IL-2) significantly increased (P < 0.05) in mice treated with both SeNPs and crude antigens of 4T1 cells in comparison to the other groups. In contrast, the levels of TGF-β in these mice decreased.

CONCLUSIONS

Although SeNPs showed a noticeable boosting effect for the immune response in mice bearing tumor exposed to crude antigens of 4T1 cells, further complementary studies seem to be inevitable.

Carboxylic group-induced synthesis and characterization of selenium nanoparticles and its anti-tumor potential on Dalton's lymphoma cells

Carboxylic group-induced synthesis of selenium nanoparticles (SeNPs) was achieved using sodium selenosulphate as a precursor. The particles were stabilized and capped with 0.01% polyvinyl alcohol under ambient conditions. This is a simple and easy method of producing SeNPs in a size range from 35 to 105 nm. The synthesized SeNPs were purified by centrifugation at 11,500 × g for 20 min and characterized by UV-visible spectroscopy, FTIR spectroscopy, XRD, DSC and TEM. It was observed that the synthesized SeNPs showed differences in their absorption spectra, phase composition and crystal structure, thermodynamic behaviour, size and shape. Further, to confirm anti-tumour potential of the synthesized SeNPs induced by the carboxylic group of acetic acid, pyruvic acid and benzoic acid, cell viability assay, nuclear morphology testing and DNA fragmentation assay were carried out using Dalton's lymphoma (DL) cells. DL cells treated with the SeNPs showed reduced cell viability, altered nuclear morphology, typical apoptotic DNA ladder and apoptosis. Therefore, these SeNPs may have therapeutic relevance to treat this type of cancer.