Biosynthesized Selenium Nanoparticles Research Articles

Green and ecofriendly biosynthesis of selenium nanoparticles using Urtica dioica (stinging nettle) leaf extract: Antimicrobial and anticancer activity.

Plant extract is affordable and does not require any particular conditions; rapid production of nanoparticles using plants offers more advantages than other approaches. Selenium nanoparticles (SeNPs) have received much attention in the last decade due to SeNPs diverse and different applications. Herein, this study aimed to biosynthesize SeNPs using aqueous extract of Urtica dioica leaf through green and ecofriendly method. Moreover to fully characterize SeNPs using different techniques, and to evaluate it for antimicrobial activity as well as anticancer activity. SeNPs were biosynthesis using aqueous leaf extract of U. dioica (stinging nettle). The biosynthesized SeNPs were characterized using UV-visible spectroscopy (UV-Vis), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive electron spectroscopy (EDX), transmission electron microscopy (TEM), and thermal-gravimetric analysis (TGA). Antimicrobial and anticancer activities of biosynthesized SeNPs were assessed. Results illustrated that SeNPs exhibited promising antibacterial activity against Gram-positive and Gram-negative bacteria, as well as unicellular and multi-cellular fungi. Moreover, minimal-inhibitory concentration (MIC) of SeNPs against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus were 250, 31.25, and 500μgmL-1 , respectively, while were 62.5, 15.62, 31.25, and 7.81μgmL-1 against Candida albicans, Aspergillus fumigatus, Aspergillus niger, and Aspergillus flavus, respectively. The cytotoxicity of SeNPs was performed on Vero normal-cell line CCL-81, where IC50 was 173.2μgmL-1 . For the first time, aqueous stinging nettle leaf extract was utilized to biosynthesize SeNPs in a green method. SeNPs have outstanding antimicrobial-activity against pathogenic bacterial and fungal strains. Moreover, SeNPs have promising anticancer activity against HepG2 cancerous cell line without cytotoxicity on Vero normal cell line. Finally, the biosynthesized SeNPs via aqueous extract of stinging nettle leaf exhibited potential antibacterial, antifungal, and anticancer action, making them useful in the medical field.

Antibacterial Activity of Biosynthesized Selenium Nanoparticles Using Extracts of Calendula officinalis against Potentially Clinical Bacterial Strains.

The use of selenium nanoparticles (SeNPs) in the biomedical area has been increasing as an alternative to the growing bacterial resistance to antibiotics. In this research, SeNPs were synthesized by green synthesis using ascorbic acid (AsAc) as a reducing agent and methanolic extract of Calendula officinalis L. flowers as a stabilizer. Characterization of SeNPs was performed by UV-vis spectrophotometry, infrared spectrophotometry (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM) techniques. SeNPs of 40–60 nm and spherical morphologies were obtained. The antibacterial activity of marigold extracts and fractions was evaluated by disk diffusion methodology. The evaluation of SeNPs at different incubation times was performed through the colony-forming unit (CFU) count, in both cases against Serratia marcescens, Enterobacter cloacae, and Alcaligenes faecalis bacteria. Partial antibacterial activity was observed with methanolic extracts of marigold leaves and flowers and total inhibition with SeNPs from 2 h for S. marcescens, 1 h for E. cloacae, and 30 min for A. faecalis. In addition, SeNPs were found to exhibit antioxidant activity. The results indicate that SeNPs present a potentiated effect of both antimicrobial and antioxidant activity compared to the individual use of marigold extracts or sodium selenite (Na2SeO3). Their application emerges as an alternative for the control of clinical pathogens.

Biosynthesized selenium nanoparticles: characterization, antimicrobial, and antibiofilm activity against Enterococcus faecalis.

BackgroundControl over microbial growth is a crucial factor in determining the success of endodontic therapy. Enterococcus faecalis is the most resistant biofilm-forming species leading to endodontic failure. Hence, the current researches are directed towards discovering materials with superior disinfection properties and lesser cytotoxicity. This study aimed to synthesize and characterize biogenically produced Selenium Nanoparticles, and to evaluate the antimicrobial and antibiofilm efficacy, against Enterococcus Faecalis, for the following test groups: Group I: Distilled water (control), Group II: SeNPs (1 mg/ml), Group III: Calcium hydroxide (1 mg/ml), Group IV: 2% Chlorhexidine gluconate (CHX), Group V: 5.25% Sodium hypochlorite (NaOCl).Materials and MethodsSelenium nanoparticles were derived using fresh guava leaves (Psidium guajava) and were characterized. The antibacterial efficacy against E. faecalis was evaluated by agar well diffusion method. The antibiofilm efficacy of the test groups was observed by viable cell count, antibiofilm assay, and Anthrone and Bradford’s tests. The morphology of the biofilms was analysed using the Scanning Electron Microscope and Fourier Transform Infrared spectroscopy.ResultsAntibacterial and antibiofilm efficacy of all tested solutions showed superior antibacterial and antibiofilm efficacy when compared to the control group. Overall, SeNPs (Group II) was the most effective against E. faecalis biofilm, followed by NaOCl (Group V), CHX (Group IV), and Ca(OH)2 (Group III).ConclusionBiogenically produced SeNPs emerged as a novel antibacterial and antibiofilm agent against E. faecalis. This nano-formulation demonstrates the potential to be developed as a root canal disinfectant combating bacterial biofilm in endodontics after the results have been clinically extrapolated.

Biosynthesized Selenium nanoparticles as a new catalyst in the synthesis of quinazoline derivatives in pentacyclic system with docking validation as (TRPV1) inhibitor

In recent years, a lot of benefits of Selenium have been discovered for humans, animals and chemical uses. Nano-Selenium was biosynthesized and characterized by using FTIR, UV/Vis., TEM/SAED, and mapping to ensure their crystallinity. The N-bridged imidazo-quinazoline derivatives were successfully synthesized in pentacyclic nonlinear ortho fused polynuclear by a one-pot reaction of aldehyde, β-naphthol, and 2-aminobenzoimidazole in the presence of a catalytic amount of aqueous nano-Se as a highly efficient and facile catalyst at 70–80 °C. The molecular docking study as TRPV1 inhibitor compared with Rutaecarpine and Evodiamine as reference alkaloids ligands.

Green Biosynthesized Selenium Nanoparticles by Cinnamon Extract and Their Antimicrobial Activity and Application as Edible Coatings with Nano-Chitosan

Bioactive nanocomposites were constructed, containing chitosan (Cht), extracted from shrimps’ wastes, and transformed into nanoparticles (NPs) using ionic-gelation. Selenium NPs (Se-NPs) were phytosynthesized using cinnamon (Cinnamomum zeylanicum) bark extract (CIE), characterized and evaluated with Cht-NPs as antimicrobial composites against bacterial food-borne pathogens “Escherichia coli, Salmonella typhimurium, Staphylococcus aureus, and Listeria monocytogenes” and as potential edible coating (EC) basements. The CIE-phytosynthesized Se-NPs had well-distributed and spherical shapes with 23.2 nm mean diameter. The CIE, CIE/Se-NPs, and innovative CIE/Se/Cht-NP composites exhibited distinguished antibacterial actions toward the entire screened pathogens; CIE/Se/Cht-NP composite was significantly the most potent. The formulated ECs from CIE/Se/Cht-NP nanocomposites had matching antibacterial manner, which was strengthened with CIE/Se-NP percentage increments. Scanning micrographs indicated the attachment of CIE/Se-NPs to bacterial cells to cause their complete lysis and death after 10 h of exposure. CIE/Se/Cht-NP composites are proposed as effectual control agents toward food-borne pathogens using efficient biological carriers and eco-friendly phytosynthesis protocol.

Bacillus megaterium-Mediated Synthesis of Selenium Nanoparticles and Their Antifungal Activity against Rhizoctonia solani in Faba Bean Plants.

Rhizoctonia root-rot disease causes severe economic losses in a wide range of crops, including Vicia faba worldwide. Currently, biosynthesized nanoparticles have become super-growth promoters as well as antifungal agents. In this study, biosynthesized selenium nanoparticles (Se-NPs) have been examined as growth promoters as well as antifungal agents against Rhizoctonia solani RCMB 031001 in vitro and in vivo. Se-NPs were synthesized biologically by Bacillus megaterium ATCC 55000 and characterized by using UV-Vis spectroscopy, XRD, dynamic light scattering (DLS), and transmission electron microscopy (TEM) imaging. TEM and DLS images showed that Se-NPs are mono-dispersed spheres with a mean diameter of 41.2 nm. Se-NPs improved healthy Vicia faba cv. Giza 716 seed germination, morphological, metabolic indicators, and yield. Furthermore, Se-NPs exhibited influential antifungal activity against R. solani in vitro as well as in vivo. Results revealed that minimum inhibition and minimum fungicidal concentrations of Se-NPs were 0.0625 and 1 mM, respectively. Moreover, Se-NPs were able to decrease the pre-and post-emergence of R. solani damping-off and minimize the severity of root rot disease. The most effective treatment method is found when soaking and spraying were used with each other followed by spraying and then soaking individually. Likewise, Se-NPs improve morphological and metabolic indicators and yield significantly compared with infected control. In conclusion, biosynthesized Se-NPs by B. megaterium ATCC 55000 are a promising and effective agent against R. solani damping-off and root rot diseases in Vicia faba as well as plant growth inducer.

Catalytical degradation of industrial dyes using biosynthesized selenium nanoparticles and evaluating its antimicrobial activities

The release of textile dyes from the industries to the environment has become a significant health issue to humans and their surroundings, where a large number of dyes are wasted to the nearby water during the dyeing process. Therefore, the practice of the utilization of biosynthesized nanoparticles from numerous biological systems has been described, out of which plant material is considered the most appropriate method. The usage of plant material not only makes the procedure ecological but also their abundance makes it more cost-effective. The present study aims to biologically produce selenium nanoparticle using Mucuna pruriens seed powder and apply it in the degradation of dyes and removal of pathogenic bacterial cultures from pathogen-containing lake water using an optimum concentration of selenium nanoparticles. The production of selenium nanoparticles was characterized via visual coloration from colorless to brown solution which was checked using UV–Visible spectrophotometer, the crystalline structure was analyzed using X-ray diffraction, the morphology was analyzed with transmission electron microscopy, scanning electron microscopy, dynamic light scattering, which was in the range of 90–120 nm, with stable spherical monodisperse characteristics. The surface potential was checked using zeta potential, while the Atomic Force Microscopy gave information on the roughness of the nanoparticles, and the presence of –OH, −COO, aromatic groups were confirmed with Fourier Transform Infrared spectroscopy. The biosynthesized nanoparticles were then analyzed for its environmental applications, like degradation of dyes from industrial wastes and checking its antimicrobial activities.

Antibacterial properties and mechanism of selenium nanoparticles synthesized by Providencia sp. DCX

Selenium nanoparticles (SeNPs) have attracted great interest as a potential antimicrobial agent. However, there is limited research on the antibacterial activity and possible mechanisms of biosynthesized SeNPs. In this study, spherical bio-SeNPs with an average size of 120 nm were synthesized by strain Providencia sp. DCX. The SeNPs were further applied to investigate the antibacterial properties of model bacteria, including Gram-positive (Staphylococcus aureus, Bacillus cereus and Bacillus subtilis) and Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli and Vibrio parahemolyticus). The biosynthesized SeNPs demonstrated strong inhibition activity against the growth of these pathogens. When treated with 500 mg/L SeNPs, most of the tested bacteria were destructed within 12 h, among which the mortality rates of Gram-negative bacteria were much better. The leakage tests illustrated that there existed more proteins and polysaccharides outside the cells after reacted with bio-SeNPs. It was indicated that the leakages of proteins and polysaccharides were caused by permeability changes of membranes and the disruption of cell walls. And the change of reactive oxygen species (ROS) intensity indicated that oxidative damage may play the significant role in the antibacterial processes. The results showed that several bacteria could be effectively inhibited and destructed, suggesting the potential of using the biosynthesized SeNPs as antibacterial agents for bacterial infectious diseases.

A Green Approach to the Bio-based Synthesis of Selenium Nanoparticles from Mining Waste

This study deals with producing selenium nanoparticles (SeNPs) by an economical and reliable process using a mining waste that contains significant amounts of selenium (6.11%), silver (4.12%), lead (4.69%), copper (3.61%), antimony (4.97%) and barium sulfate (70.01%). For separation of valuable metals and obtaining a pure solution for Se synthesis, several steps need to be taken; (a) Barium sulfate removal by gravity separation; (b) Leaching of the concentrate by HNO3 (3M); (c) Precipitation of silver and lead as insoluble chloride salts and (d) removing of other impurities such as arsenic, tellurium and strontium. The solution of purified selenium stock was then utilized as a precursor for the green synthesis of SeNPs using fruit extracts via an eco-friendly approach. The different fruit extracts such as plum, grape, orange, pomegranate, tomatoes, and lime were examined, and orange extract was found to be an efficient, reducing agent as well as a stabilizer for green synthesis of SeNPs. The biosynthesized SeNPs were characterized by various techniques such as SEM, TEM, XRD, FTIR and EDX. The spherical morphology of SeNPs was confirmed by SEM and TEM analysis, and particle size of SeNPs was found between 70 and 80 nm on the basis of the Debye–Scherrer equation.

Cytotoxicity and antimicrobial efficiency of selenium nanoparticles biosynthesized by Spirulina platensis.

Nanotechnology has been exploited as a great scientific area especially in stating scenarios in drug discovery. In the present study, biosynthesized selenium nanoparticles (SeNPs) were prepared by the filtrate of Spirulina platensis after ultrasonication of their biomass. The biosynthesized SeNPs was characterized by using ultra-violet visible, Fourier transform infra-red spectroscopy, dynamic light scattering, and transmission electron microscope (TEM). The zeta potential of Biogenic SeNPs was -32.9 ± 8.12 mv that caused their stability. TEM micrographs elucidated the spherical shape of Biogenic SeNPs with a mean average size of 79.40 ± 44.26nm. Biogenic SeNPs showed potential antimicrobial activity against gram-negative bacteria and yeast fungi C. albicans ATCC10231. No toxic effect was observed for SeNPs on normal kidney and liver cell lines. Biogenic SeNPs could be considered as a hopeful choice for future therapeutic applications because of their good biocompatibility and reactivity.

Hybrid of niosomes and bio-synthesized selenium nanoparticles as a novel approach in drug delivery for cancer treatment.

The currentstudyintends to investigate a novel drug delivery system (DDS) based on niosomes structure (NISM) and bovine serum albumin (BSA) which was formulated to BSA coated NISM (NISM-B). Also, selenium nanoparticles (SeNPs) have been prepared by BSA mediated biosynthesis. Finally, the NISM-B was hybridized with SeNPs and was formulated as NISM-B@SeNPs for drug delivery applications. Physicochemical properties of all samples were characterized by UV-Vis spectroscopy, FT-IR, DLS, FESEM, and EDX techniques. The cytotoxicity of all samples against A549 cell line was assessed by cell viability analysis and flow cytometry for apoptotic cells as well as RT-PCR for the expression of MDR-1, Bax, and Bcl-2 genes. Besides, in vivo biocompatibility was performed by LD50 assay to evaluate the acute toxicity. The proposed formulation has a regular spherical shape and approximately narrow size distribution with proper zeta-potential values; the proposed DDS revealed a good biocompatibility. The compound showed a significant cytotoxic effect against A549 cell line. Although the Bax/Bcl-2 expression ratio was significantly in NISM-B@SeNPs- treated cancer cells, the expression of MDR-1 was non-significantly lower in NISM-B@SeNPs-treated cancer cells. The obtained results suggest that the proposed DDS presents a promising approach for drug delivery, co-delivery and multifunctional biomedicine applications.

Toxicological impact of green synthesized silver nanoparticles and protective role of different selenium type on Oreochromis niloticus: hematological and biochemical response

BackgroundThe present work aimed to detect the toxicological effects of green synthesized silver nanoparticles (Ag-NPs) by using Moringa Oleifera leaves extract on hematological and biochemical parameters of Oreochromis niloticus. MethodsAdult fish were exposed to two sublethal concentrations (1.95 and 3.9 ppm) of Ag-NPs against sodium selenite (0.1 ppm) and biosynthesized selenium nanoparticles (Se-NPs); 0.1 ppm; protection role for 2 and 4 weeks. Hematological parameters; erythrocyte count (RBCs), hemoglobin content (Hb), haematocrit value (Hct), mean corpuscular volume (MCV), Mean Corpuscular Hemoglobin Concentration (MCHC), leucocytes (WBCs), with differential count Micronucleus (MN) and alerted cells and biochemical parameters; aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) enzyme activities, serum protein (total protein, albumin and globulin) concentration, urea, creatinine, glucose, cholesterol (Cho) and triglyceride (Tg) were detected. ResultsThe present investigation showed that Ag-NPs in different doses led to a significant reduction (p < 0.05) in RBCs, Hb, Hct, MCV, WBCs, LYM and serum proteins concentration. However, MCHC, MN, alerted cells, NEUT, AST, ALT, ALP enzyme activities, urea, creatinine, glucose, Cho and Tg showed a significant increases (p < 0.05) when compared with control group. Sodium selenite (Se) and biosynthesized selenium nanoparticles (Se-NPs) play an optimistic role in detoxification of Ag-NPs toxicity. ConclusionThe results suggest the negative impact of Ag-NPs on hematology and biochemical parameters of fish. Moreover, Se-NPs showed a full improvement of hematological and biochemical parameters more than that of sodium selenite in elimination of Ag-NPs toxicity.

Rapid and size-controlled biosynthesis of cytocompatible selenium nanoparticles by Azadirachta indica leaves extract for antibacterial activity

Biosynthesized selenium nanoparticles (SeNPs) have achieved considerable importance in biomedical applications owing to their biocompatibility and low toxicity. In this study, rapid and size-controlled biosynthesis of SeNPs by aqueous leaves extract of Azadirachta indica is reported. SeNPs were synthesized by reduction of Se+ ions of sodium selenite salt to elemental selenium. Biosynthesized SeNPs were crystalline in nature and spherical in shape with a smooth surface. The size of these SeNPs was controlled by adjusting the time of reduction reaction. Accordingly, SeNPs of size range 142 to 168 nm and 221 to 328 nm were synthesized after 5 and 10 min of reaction respectively with 10 mM initial concentration of sodium selenite. Fourier Transform- Infra Red (FT-IR) analysis revealed the presence of plant extract molecules on the surface of SeNPs acting as reducing agent and capping molecules. These biosynthesized SeNPs were found to be cytocompatible in nature when tested in-vitro against the L929 cell line by MTT assay. In addition, these biosynthesized SeNPs showed promising antibacterial activity against selected Gram-positive and Gram-negative bacterial strains.

Investigating the Antimicrobial Activities of the Biosynthesized Selenium Nanoparticles and Its Statistical Analysis

The present investigation concentrates on the green combination of biosynthesized selenium nanoparticles utilizing aqueous extract of cow urine as a green technique with no external chemicals, reagents, or surfactants. The combination of parameters, for example, the sodium selenite precursor concentration, or the concentration of cow urine extract, time of synthesis, and pH on the particle size of combined selenium particles, was explored and enhanced. The participation of the factors in controlling the particle size of reduced SeNPs was quantitatively evaluated by means of analysis of variance (ANOVA). The UV-Vis spectroscopy was utilized to screen the selenium nanoparticle development followed by electron microscopy (SEM and TEM), DLS, AFM, and EDAX. The optimized nanoparticles were subjected to antibacterial activity against Gram-positive and Gram-negative cultures, out of which the highest activity was observed for Klebsiella sp. The biosynthesized and optimized selenium nanoparticles can be further used for various pharmaceutical or industrial applications.

In vitro and in vivo toxicity assessment of selenium nanoparticles with significant larvicidal and bacteriostatic properties

In the present study, we investigated the larvicidal and bacteriostatic activity of biosynthesized selenium nanoparticles using aqueous berry extract of Murraya koenigii (Mk-Se NPs). The synthesized Mk-Se NPs were characterized using UV–visible spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis. XRD analysis revealed the crystalline nature of Mk-Se NPs as hexagonal. The FTIR spectra of Mk-Se NPs exhibited a strong peak at 3441 cm−1 corresponding to the OH group. SEM and TEM analysis showed that the Mk-Se NPs were spherical in shape with a size between 50 and 150 nm. EDX peaks confirm the presence of 73.38% of selenium and 26.62% of oxide in Mk-Se NPs. Mk-Se NPs showed significant larvicidal property against the 4th instar larvae of a dengue fever-causing vector Aedes aegypti with LC50− – 3.54 μg mL−1 and LC90− – 8.128 μg mL−1 values. Mk-Se NPs displayed anti-bacterial activity against Gram-positive (Enterococcus faecalis &Streptococcus mutans) and Gram-negative (Shigella sonnei &Pseudomonas aeruginosa) bacteria at 40 and 50 μg mL−1. In addition, Mk-Se NPs reduced bacterial biofilm thickness extensively at 25 μg mL−1. The high antioxidant property at 50 μg mL−1 and low hemolysis activity till 100 μg mL−1 proved the biocompatible nature of Mk-Se NPs. In vitro and in vivo toxicity assessment of Mk-Se NPs showed low cytotoxicity against RAW 264.7 macrophages and Artemia nauplii. Together, our results suggest the potential application of Mk-Se NPs as a nano-biomedicine.

Detoxification and anti-mycotoxigenic effect of Ochratoxin A produced by Penicillium expansum species utilizing probiotic Pichia kudriavzevii and biogenic-selenium nano-formulations

Ochratoxins are overall spread fungal secondary metabolites combined chiefly by some toxigenic types of Aspergillus and Penicillium. A few physical, chemical and biological techniques were found among literary reports to wipe out, inactivate or decrease the bioavailability of mycotoxins counting ochratoxin A (OTA). Concerning the creation of OTA, Penicillium expansum strains inspected in this examination using TLC were recorded surprisingly for the first time. They were subjected to the beforehand announced probiotic yeast Pichia kudriavzevii, biosynthesized Selenium nanoparticles (SeNPs) and consolidated plans of both to look at their capability to detoxificate or lessening of this mycotoxin. Every single tried experiment was found to be capable for diminishing OTA as confirmed by the quantitative assessment using HPLC. Where, the blend of Pichia kudriavzevii and SeNPs-plans demonstrated that most of OTA evacuation rate created by P.expansum5 (50.18 %). While the least OTA expulsion rate was watched delivered by P.expansum3 (76.08%) treated with SeNPs as it were. The ultrastructural investigations of P.expansum5 cells completed with TEM demonstrated the continuous harm of the fungal cells constituents as it appeared from the investigations. The most elevated impacts were seen among the cytoplasmic constituents of P.expansum5 cells treated with the previous blend of probiotic and SeNPs that were totally contracted and pulled back far from the cell membrane leaving a gigantic separation region of no organelles. Remarkable cytoplasmic ultrastructure's deformations of P.expansum5 cells with appearance of some vacuolation as a survival adaptation mode of the fungal cells were additionally recorded. Conclusively, this is the primary statement of OTA biodegradation using a combination strategy of probiotic yeast Pichia kudriavzevii and biogenic-SeNPs which endorsing the impact of utilizing these novel natural blends for the detoxification, anti-mycotoxigenic and/or diminution of OTA production by mycotoxegenic fungal species. This natural mixture could be recommended to be utilized as a food/feed additive, during storage and as prophylactic agent in pre-and post-harvest crops.

Antioxidant activity and green synthesis of selenium nanoparticles using allium sativum extract

&lt;p&gt;&lt;strong&gt;Abstract&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;The green synthesis of nanoparticles has provided cost effective, environment friendly procedure and raising safe strategies for synthesis of non-materials. In this study we investigated the clove of &lt;em&gt;Allium sataivum&lt;/em&gt;, which is used for the synthesis of Selenium nanoparticles. The biosynthesized selenium nanoparticles were characterized by using UV-Visible (UV-VIS) spectrophotometer, Transmission electron microscopy (TEM), Fourier transform spectroscopy (FT-IR) and Energy dispersive X-Ray spectroscopy (EDAX). The selenium nanoparticles synthesized by garlic were observed as hollow and spherical particles in size ranging 7-45nm which is found more stable more than two months. The present study also reports the efficiency of ABTS, DPPH and FRAP assay to estimate the antioxidant potential of selenium nanoparticles which synthesized by garlic extract.&lt;/p&gt;&lt;p&gt; &lt;/p&gt;

Improved degradation of methyl orange dye using bio-co-catalyst Se nanoparticles impregnated ZnS photocatalyst under UV irradiation

The present work outlines the importance of biosynthesized selenium nanoparticles (SeNPs) as co-catalyst for the enhanced photocatalytic activity of as-prepared ZnS photocatalyst for degradation of methyl orange (MO) dye under UV light irradiation. SeNPs of different wt% were impregnated onto ZnS by calcination at 200°C to make Se-ZnS nanocomposites (Se-ZnSNCs) and characterized by UV–Vis spectroscopy, DLS, XRD, SEM-EDX, TEM and BET surface area analysis. The specific surface area notably increased from 54m2g−1 (ZnS) to 75m2g−1 with different wt% of Se loading. The band edge absorption at 330nm (3.77eV) of bare ZnS significantly red-shifted to 357nm (3.30eV), after 1wt% Se loading (3.30eV). 1wt% Se-ZnSNCs exhibited the highest degradation efficiency (95%) of MO as compared to bare ZnS (55%) under 160min UV light irradiation. The reaction followed pseudo first-order kinetics with an apparent rate constant k=8.42×10−3min−1 where CO2 evolution gradually increased depending on the extent of MO degradation by Se-ZnSNCs under different time period of UV light irradiation.

Green synthesis and structural characterization of selenium nanoparticles and assessment of their antimicrobial property.

In the present study, selenium nanoparticles were biologically synthesized by non-pathogenic, economic and easy to handle bacterium Ralstonia eutropha. The selenium oxo anion was reduced to selenium nanoparticles in the presence of the bacterium. The bacterium was grown aerobically in the reaction mixture. An extracellular, stable, uniform, spherical selenium nanoparticle was biosynthesized. The TEM analysis revealed that the biosynthesized selenium nanoparticles were spherical in shape with size range of 40-120nm. XRD and SAED analysis showed that nanocrystalline selenium of pure hexagonal phase was synthesized. The formation of actinomorphic trigonal selenium nanorods was also observed. A mechanism of biosynthesis of selenium nanoparticles by R. eutropha was proposed. The biosynthesized selenium nanoparticles were investigated for their antimicrobial activity against potential pathogens. Selenium nanoparticles showed excellent antimicrobial activity. The 100, 100, 250 and 100µg/ml selenium nanoparticles were found to inhibit 99% growth of Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli and Streptococcus pyogenes, respectively. Similarly, the 500µg/ml of selenium nanoparticles was found to inhibit the growth of pathogenic fungi Aspergillus clavatus. The antimicrobial efficacy of selenium nanoparticle was comparable with commercially available antibiotic drug Ampicillin.

Antimicrobial and antibiofilm effects of selenium nanoparticles on some foodborne pathogens

Microbial biofilms, which characterized by their resistance to the traditional antimicrobials, are considered as a renewable source of contamination by pathogens. As alternative antimicrobial and antibiofilm agent selenium nanoparticles (SeNPs) were biosynthesized by treatment of 1 mM SeO2 with the free-cell supernatant of Bacillus licheniformis isolated from food wastes. The biosynthesized SeNPs were characterized by their spherical shape with diameter range of 10–50 nm and a well-defined absorption peak at 263 nm in UV–vis spectra. The biosynthesized SeNPs were used to control growth and biofilm formation by six foodborne pathogens including Bacillus cereus, Enterococcus faecalis, Staphylococcus aureus, Escherichia coli O157:H7, Salmonella Typhimurium, and Salmonella Enteritidis. The MIC90 of SeNPs against all tested bacteria was 25 μg/mL, whereas the antibiofilm concentration was 20 μg/mL against all bacteria, except B. cereus. Although the biogenic SeNPs had antimicrobial and antibiofilm effects, they did not show ability to remove the established biofilm up to 50 μg/mL. The concentration of 75 μg/mL showed slight effect on removing the established biofilm. No toxicity on Artemia larvae was demonstrated by SeNPs upto 100 μg/mL. In conclusion, SeNPs produced in the present study can be used as a promising agent for effectively preventing biofilm formation by foodborne pathogens.