Synthesis Of Selenium Nanoparticles Research Articles

Cynodon dactylon Mediated Synthesis of Selenium Nanoparticles and Its Antimicrobial Activity Against Oral Pathogens

is a genus of plant in the grass family. It is found in the tropical regions and is also known as grass, Bermuda grass and Indian Doab. It is a herb extensively used in Indian system of medicine. It has many health benefits and is useful in controlling hypertension, skin diseases and diabetes. Selenium particles have an excellent anti-cancer, , antioxidant, photo reactive property. The size of SeNPs ranges from 30nm to 200 nm. These particles can be used in arthritis, cancer, diabetes etc. To prepare the selenium particles using Cynodon , fresh Cynodon was dried and made into a fine powder and powder mixed with distilled water. Selenium were synthesized using plant extract and sodium . Anti microbial activity against oral pathogens tested usingagar well diffusion method. The diameter of zone of inhibition was recorded on each plate. The change was indicative of the formation of SeNPs that was further confirmed by . The Cynodon mediated SeNPs showed high anti microbial activity against all the three micro-organisms especially Candida and S.. Therefore, diseases can be prevented as it is very effective in inhibiting the growth of the colonies.

Characteristics of selenium nanoparticles synthesized by cell-free supernatant Cupriavidus sp. SHE

In recent years, selenium nanoparticles (SeNPs) have been widely used in many fields such as nanotechnology, biomedicine and environmental remediation due to their good electrical conductivity, photothermal properties and anticancer properties. In this study, the cell-free supernatant, whole cell and the cell-free extracts of the strain Cupriavidus sp. SHE were used to synthesize SeNPs, and several methods were applied to analyze the crystal structure and surface functional groups of the nanoparticles. Finally, Pseudomonas sp. PI1 (G⁺) and Escherichia coli BL21 (G⁻) were selected to investigate the antibacterial properties of SeNPs. Cell-free supernatant, whole cell and cell-free extracts of the strain could synthesize SeNPs. As for the cell-free supernatant, selenite concentration of 5 mmol/L and pH=7 were favorable for the synthesis of SeNPs. TEM images show that the average size of nanospheres synthesized by the supernatant was 196 nm. XRD analysis indicates the hexagonal crystals structure of SeNPs. FTIR and SDS-PAGE confirmed the proteins bound to the surfaces of SeNPs. SeNPs synthesized by cell-free supernatant showed no antimicrobial activities against Pseudomonas sp. PI1 and Escherichia coli BL21 (DE3). These results suggest that proteins played an important role in biotransformation of SeNPs in an eco-friendly process, and SeNPs synthesized in this study were non-toxic and biologically compatible, which might be applied in other fields in the future.

In vitro evaluation of bone cements impregnated with selenium nanoparticles stabilized by phosphatidylcholine (PC) for application in bone.

One of the most common prophylactic techniques to solve prosthetic joint infection (PJI) is incorporation of antibiotics into acrylic bone cement to prevent bacterial colonization and proliferation by providing local antibiotic delivery directly at the implant site. Further, there has been a significant concern over the efficacy of commonly used antibiotics within bone cement due to the rise in multi-drug resistant (MDR) microorganisms. Selenium is an essential trace element that has multiple beneficial effects for human health and its chemotherapeutic action is well known. It was reported that nanostructured selenium enhanced bone cell adhesion and has an increased osteoblast function. In this context, we used the selenium nanoparticles (SeNPs) to improve antibacterial and antioxidant properties of poly (methyl methacrylate) (PMMA) and tri calcium phosphate (TCP)-based bone cements, and to reduce of the infection risk caused by orthopedic implants. As another novelty of this study, we proposed phosphatidylcholine (PC) as a unique and natural stabilizer in the synthesis of selenium nanoparticles. After the structural analysis of the prepared bone cements was performed, in vitro osteointegration and antibacterial efficiency were tested using MC3T-E1 (mouse osteoblastic cell line) and SaOS-2 (human primary osteogenic sarcoma) cell lines, and S. aureus (Gram positive) and E.coli (Gram negative) strains, respectively. More importantly, PC-SeNPs-reinforced bone cements exhibited significant effect against E. coli, compared to S. aureus and a dose-dependent antibacterial activity against both bacterial strains tested. Meanwhile, these bone cements induced the apoptosis of SaOS-2 through increased reactive oxygen species without negatively influencing the viability of the healthy cell line. Furthermore, the obtained confocal images revealed that PC-SeNPs (103.7 ± 0.56 nm) altered the cytoskeletal structure of SaOS-2 owing to SeNPs-induced apoptosis, when MC3T3-E1 cells showed a typical spindle-shaped morphology. Taken together, these results highlighted the potential of PC-SeNPs-doped bone cements as an effective graft material in bone applications.

Effects of process conditions and yeast extract on the synthesis of selenium nanoparticles by a novel indigenous isolate Bacillus sp. EKT1 and characterization of nanoparticles.

Selenium nanoparticles (SeNPs) are attractive nanomaterials for application in medical diagnosis, because their toxicities are lower than the elemental selenium which is a functional element and essential for human. In the current study, SeNPs synthesis capability of a novel soil originated indigenous Bacillus isolate was investigated. In this context, effects of processing conditions (SeO2 concentration, pH, temperature, and time), and yeast extract supplementation on the synthesis of SeNPs have been tested. In addition, nanoparticles were characterized and antioxidant capacity was determined. The cell-free supernatant of the bacterium, which was obtained after the cultivation of the isolate in nutrient broth at 33°C for 24h, was used for the synthesis. During the synthesis color change from light yellow to red-orange was an indication of the formation of SeNPs. Effect of SeO2 concentration was tested on the formation of nanoparticles and at concentrations higher than 10mM, there was no formation of nanoparticles. The best production was achieved at 6.4mM concentration, at pH 9 and 33°C in 72h. Field emission scanning electron microscopy (FESEM) images revealed that SeNPs were spherical in shape having the diameters between 31 and 335nm, and the average diameter was determined to be 126nm. Energy dispersive X-ray spectroscopy analysis confirmed the presence of elemental selenium. SeNPs possessed significant antioxidant activity that the scavenging capacity was up to 56.5 ± 5% (IC50 322.8μg/mL).

Walnut leaf extract-based green synthesis of selenium nanoparticles via microwave irradiation and their characteristics assessment

Abstract Selenium nanoparticles (Se NPs) have predominant characteristics compared to that in their bulk usage due to their high surface-to-volume ratio. The walnut (Juglans regia L.) leaf extract containing different bioactive compounds that act as reductant and stabilizing agents has been used for the green synthesis of the Se NPs. Influences of two synthetic variables, namely, the amount of selenium salt solution ranging from 15 to 25 mL and the amount of walnut leaf extract ranging from 1 to 5 mL, on broad emission peak (λ max) and absorbance of colloidal solutions having Se NPs were evaluated via the response surface methodology. Obtained results indicated that using microwave radiation (800 W for 4 min) and 5 mL of walnut leaf extract and 15 mL of selenium salt solution, Se NPs with λ max, absorbance, particle size, polydispersity index, and zeta potential values of 375 nm, 3.65% absorbance unit (a.u.), 208 nm, 0.206, and −24.7 mV were synthesized, which had high bactericidal activity toward Escherichia coli and Staphylococcus aureus. The transmission electron microscopy analysis also indicated that spherical and monodispersed Se NPs with a mean particle size of 150 nm were formed using the walnut leaf extract.

Biogenic Synthesis of Selenium Nanoparticles with Edible Mushroom Extract: Evaluation of Cytotoxicity on Prostate Cancer Cell Lines and Their Antioxidant, and Antibacterial Activity

We report edible mushroom extract (EME) as a robust and environmentally friendly precursor for the biogenic synthesis of selenium nanoparticles (SeNPs). The as-synthesized SeNPs were characterized by UV-visible spectrophotometer (UV-vis), Fourier-transform infrared spectroscopy (FTIR), Transmission electron microscope (TEM), and Dynamic light scattering (DLS) techniques. The results obtained from TEM and DLS suggested that the SeNPs synthesized with EME are in the size of ~ 8 nm with a spherical shape and monodispersity. The occurrence of antioxidants in the EME has been confirmed with FTIR and thereby confirmed that flavonoids and phenolic compounds played a pivotal role in the biosynthesis of SeNPs from Na2SeO3. In addition, EME-SeNPs exhibited no cytotoxicity on the cell lines of prostate cancer (PC-3) at concentrations ranging from 0.5-1.5 μM. At a concentration of 0.25 mM against 1,1-diphenyl-2-picrylhydrazyl, the average scavenging level of EME-SeNPs was found to be > 80.20 %. Moreover, the percentage viability of gram-negative E.coli and gram-positive E.faecium was recorded at a high concentration of EME-SeNPs and found to be 82 % and 65 %, respectively.

Extracellular synthesis of nanoselenium from fresh water bacteria Bacillus sp., and its validation of antibacterial and cytotoxic potential

Abstract In this present study, selenium reducing bacteria were isolated from fresh water pond. The cell free supernatant from B2 strain was found to effectively reduce sodium selenite and was identified as Bacillus sp. based on 16S r RNA sequencing. The selenium nanoparticles (Se NPs) synthesised using Bacillus sp. B2 were characterised by UV- spec, XRD, FTIR, FESEM and EDX. The selenium nanoparticles exhibited maximum peak at 280 nm in UV spectrophotometric analysis due to the surface plasmon resonance. FTIR analysis of cell free supernatant from Bacillus sp. B2 and synthesised selenium nanoparticles reveals that the proteins were mainly responsible for the reduction and stabilisation of Se nanoparticles. The XRD pattern shows the synthesised Se NPs were crystalline in nature with the average size of 33.2 nm. The SEM analysis reveals the Se NPs are spherical in shape with the size range of 20-50 nm and EDX pattern shows selenium exist as major element. The antibacterial activity of the Se NPs shows activity against all the tested bacteria. The lowest MIC and MBC of Se NPs was 8 μg/200 μL against Pseudomonas aeruginosa (NCIM 5031). The cytotoxicity of SeNPs against Human non-small lung cancer cell line A549 was tested by MTT assay that showed IC50 value of 3 μg/mL. The ET/AO staining of the Se NPs treated cells further revealed the result. Based on this we conclude that fresh water bacteria Bacillus sp. B2 can be used for selenium nanoparticles synthesis which is an ecofriendly and easy process for biomedical applications.

Biogenesis of selenium nanoparticles and their anti-leukemia activity

Nanobiotechnology is an exuberant sphere of science that exhibits potential application in cancer therapy, targeted chemotherapy, molecular diagnosis and molecular imaging. Present investigation discloses green route synthesis of selenium nanoparticles leading to functionalization as anti leukemia nanomaterial. Emergence of resistance over cancer radiotherapy and chemotherapy is found to be the key factor behind the clinical treatment failure and recurrence. Selenium nanoparticles (SeNPs) with distinctive physicochemical features emerged as a novel nanocarrier and therapeutic agent with broad spectrum of medicinal properties. On the basis, biogenic technology has been proposed to synthesize selenium nanoparticles using Cassia auriculata and characterized using standard techniques. Newly synthesized selenium nanoparticles’ UV intense peak is achieved at 252 nm with crytalline surface morphology clear in SEM analysis. Cassia auriculata mediated selenium nanoparticles’ TEM analysis exhibits polydispersed with 10–20 nm. FTIR spectrum confirms the reduction of carboxyl group and capping of alkane group in Cassia auriculata synthesizes the selenium nanoparticles and its anti cancer potentiality has been explored by anti-leukemia activity using in vitro studies.

Synthesis of Selenium Nanoparticles using Sodium Selenite [Se(IV)] as A Precursor and Titanium(III) Chloride as A Reducing Agent

Synthesis of Selenium Nanoparticles using Sodium Selenite [Se(IV)] as A Precursor and Titanium(III) Chloride as A Reducing Agent - written by Rajkumar Kalaparthi , Srija Korapu , Himabindu Gandam published on 2020/04/20 download full article with reference data and citations

Sustainable approach to almond skin mediated synthesis of tunable selenium microstructures for coating cotton fabric to impart specific antibacterial activity

Currently, the synthesis of nanostructured inorganic materials with tunable morphology is still a great challenge. In this study, almond skin extract was employed for the biogenic synthesis of selenium nanoparticles with tunable morphologies such as rods and brooms. The effects of various synthesis parameters on morphologies were investigated using UV–Visible spectroscopy and scanning electron microscopy (SEM) which indicated that selenium brooms (SeBrs) were best synthesized using almond skin extract and optimized conditions of SeO2, ascorbic acid, pH, incubation temperature and time. Based on these results, the mechanism of SeBrs synthesis is proposed as having involved four stages such as nucleation, self-assembly, Ostwald ripening, and decomposition. Further, the test of antibacterial activity together with minimum inhibitory concentrations and minimum bactericidal concentrations indicated the selective, specific and good activity against B. subtilis. In addition, in situ coating of SeBrs on cotton fabric and its investigation by SEM demonstrated successful coating. Evident from plate-based assay and study of growth kinetics, coated fabric exhibited excellent anti-B. subtilis activity which demonstrated that biogenic SeBrs can be employed to coat cotton fabrics that can be used in operation theatres to reduce the episodes of Bacillus related Bacteraemia.

Selenium Nanoparticles-Embedded Chitosan Microspheres and Their Effects Upon Alcohol-Induced Gastric Mucosal Injury in Rats: Rapid Preparation, Oral Delivery, and Gastroprotective Potential of Selenium Nanoparticles.

BackgroundSelenium (Se) is an indispensable trace element required for animals and human beings, whereas Se-deficiency can accelerate the development of acute gastric injury induced by over-consumption of alcohol. Selenium nanoparticles (SeNPs), as a special Se-supplement with favorable properties and unique bioactivities, are expected to play a passive role in gastroprotection. To the best of our knowledge, the gastroprotective potential of SeNPs is unknown and also, a rapid preparation of orally stable SeNPs available for prospective commercial application in the clinic is needed. Thus, SeNPs-embedded chitosan microspheres (SeNPs-CM) were developed to deliver SeNPs, and their gastroprotective potential was evaluated.ResultsHerein, a rapid, eco-friendly and economic preparation process, composed of synthesis of SeNPs decorated by chitosan (CS), purification of CS-SeNPs by ultra-filtration (UF) and spray-drying of the purified CS-SeNPs, was introduced to prepare SeNPs-CM. The uniformly distributed SeNPs with a nanosize range of 60 nm were loaded into CS-microspheres, and they could be released from the microspheres in gastric conditions. In addition, SeNPs-CM were safer than selenite in terms of Se dose, with a LD50 of around 8-fold of that of selenite, and it could efficiently enhance the Se retention in Se-deficient Wistar rats. Furthermore, SeNPs-CM pre-treatment might significantly attenuate the ethanol-induced gastric mucosal damage, based on histological evaluation. It might be partly attributed to the systematic antioxidant activities of SeNPs-CM, reflected by the reduction in lipid peroxidation, the augmentation in antioxidant enzymatic activity as well as decreasing aggressive nitric oxides (NO).ConclusionSeNPs-CM could be taken into consideration as a prospective Se-supplement for the oral delivery of SeNPs, with prominent gastroprotective effect against ethanol-induced mucosal injury.

Biosynthesis of selenium nanoparticles and their protective, antioxidative effects in streptozotocin induced diabetic rats

ABSTRACT Green synthesis of selenium nanoparticles (Se NPs) was performed by mixing Hibiscus sabdariffa (roselle plant) leaf extract with the solution of selenious acid (H2SeO3) under continuous stirring conditions resulting the roselle plant secondary metabolites conjugated Se NPs. The existence of functional groups of roselle plant secondary metabolites on the surface of prepared Se NPs was confirmed by Fourier transform infrared spectroscopy (FTIR). The formation of crystalline nanoparticles with anisotropic shape was confirmed by transmission electron microscopy (TEM) images. Furthermore, we also studied anti-oxidative and protective effects of Se NPs in streptozotocin (STZ) induced diabetes rats. These STZ induced diabetic rats were daily exposed to Se NPs or/and insulin treatment and the effect of Se NPs on the factors correlated to oxidative damage in the rat testes were evaluated. The biochemical studies showed that the Se NPs are capable to enhance the serum testosterone reduction caused due to STZ induced diabetes. In addition, Se NPs can significantly reduce the oxidative stress indicators of the testicular tissue such as nitric oxide and lipid peroxidation. However, the treatment of Se NPs on the STZ induced diabetic rats increased the activities of antioxidant enzyme as well as the glutathione content in testicular tissues. Furthermore, microscopic studies revealed that the Se NPs are capable of preventing the histological damage in the testes of STZ induced diabetic rats. Altogether, these results explained the possible effects of Se NPs in attenuating oxidative damage induced by diabetes, especially in the testicular tissue.

Enhanced Antimicrobial and Cytotoxicity on Cancer Cell using Bio-Originated Selenium Nanoparticles

Present work describes the bio-originated synthesis of selenium nanoparticles using seed extract of Cassia angustifolia. The biological macromolecules in seed extract react with metal ions to generate selenium nanoparticles. The seed extract acts as reducing, capping and stabilizing agents. The selenium nanoparticles produced by the plant extract are amorphous, nearly spherical in shape and held together by protein coating in a range of about 80-100 nm in size, under ambient conditions. The structural properties of selenium nanoparticles were characterized by UV-visible spectroscopy, FTIR, XRD, FESEM with EDAX, HRTEM and AFM. Antibacterial and antifungal activity of selenium nanoparticles were tested against four bacterial and two fungal strains using standard agar-well diffusion method. The zone of inhibition was observed in the selenium nanoparticles against different microbes and suggested that the bio-originated selenium nanoparticles act as an effective antibacterial and antifungal agent, so it has a great latent in the preparation of drugs used against pathogenic diseases. The cytotoxicity of bio-originated selenium nanoparticles was tested under in vitro conditions on Vero cell line and had compared with MDA-MB231 cancer cell line at different concentrations and the results had proved that bio-originated synthesis selenium nanoparticles can inhibit the growth of human breast-cancer cells by concentration-dependent manner.

Solid-state fermentation for enhanced production of selenium nanoparticles by gamma-irradiated Monascus purpureus and their biological evaluation and photocatalytic activities.

Selenium nanoparticles (SeNPs) were successfully synthesized using the culture extract of Monascus purpureus ATCC16436 grown on sugarcane bagasse under solid-state fermentation. The rapid synthesis of SeNPs was completed after 30min as confirmed by UV-Vis spectroscopy. Functional groups present in the synthesized SeNPs samples were confirmed by Fourier transform infrared spectroscopy. The synthesized SeNPs showed a single-phase crystalline structure. Transmission electron microscope revealed the spherical shape and the mean particle size was 46.58nm. Dynamic light scattering analysis showed that the synthesized SeNPs were monodispersed and the recorded polydispersity index value was 0.205. Zeta potential value of - 24.01mV indicated the high stability of SeNPs. Besides, the biological activities of antioxidant, anticancer and antimicrobial as well as the photocatalytic activities were also studied. SeNPs showed promising antioxidant activity with 50% inhibitory concentration of 85.92µgmL-1. Based on the MTT assay, SeNPs inhibited the proliferation of normal human melanocytes, human breast and liver cancer cell lines with 50% inhibitory concentrations of 45.21, 61.86 and 200.15µgmL-1, respectively. SeNPs showed broad spectrum of antimicrobial potential against the tested human and plant pathogens. SeNPs showed efficient degradation of methylene blue dye. Moreover, the effect of gamma irradiation on the production enhancement of SeNPs was also adopted. Exposure of the fungal spores to gamma rays at 1000Gy increased the yield of SeNPs to approximately fivefold. Hence, this study suggests a new and alternate approach with the excellent biotechnological potentiality for the production of SeNPs.

Optimal synthesis conditions and characterization of selenium nanoparticles in Trichoderma sp. WL-Go culture broth

Selenium nanoparticles (SeNPs) was synthesized by a simple, environmentally benign SeO2-reduction process in Trichoderma sp. WL-Go culture broth and followed by filtration to obtain culture broth supernatant which was then characterized. The optimal conditions for the SeNPs synthesis were pH 8, inoculation time of SeO2 at 24 h and SeO2 concentration of 2 mM. The supernatant analysis with UV–vis indicated a visible peak at 550 nm whilst TEM showed the presence 20–220 nm spherical and pseudo-spherical Se particles. Furthermore, XRD analysis confirmed the crystalline structure of the SeNPs exhibiting diffraction peaks assigned as (100), (101) and (102) plane of the nanoparticles. FTIR analysis revealed the presence of functional groups of alkene, alkane and alcohol groups that might have participated in the SeNPs synthesis reactions. The SeNPs showed electrokinetic potential of −24.6 mV at pH 7.22 after washing. DLS analysis also indicated that the particles had an average particle size to of 147.1 nm. SDS-PAGE analysis of the supernatant also showed two protein peaks at ⁓19 kDa and ⁓15 kDa which might have served as reducing and capping agents. Selenium removal rate of 84.73% was achieved thus giving the bases for future research under diverse experimental conditions using Trichoderma sp. WL-Go.

Biosynthesis of selenium nanoparticles from Bacillus species and its applications

Selenium nanoparticles have been widely used in the various areas especially in medical field for its anticancer and immune modulatory properties. To reduce the toxic chemicals released by chemical process, the present work was aimed at synthesis of selenium nanoparticles by microbes. In this study, microbes were isolated from soil samples from different areas of Bangalore and screened for the antioxidant activity by DPPH assay. The organism with highest antioxidant activity (IC50 value = 11.6µg/mL) was identified as Bacillus species. Under experimental conditions, this microbe along with sodium selenite synthesised selenium nanoparticle indicated by the colour change of the medium to reddish orange. The synthesised selenium nanoparticles were further characterised. From UV-Vis spectrophotometry, the maximum peak was obtained at 266.5nm. The FT-IR analysis showed peaks at different wavelengths with the maximum of 3200cm-1 showing the presence of alcoholic group. The shape and size of the selenium nanoparticles was also calibrated by SEM analysis as oval and 209nm-748nm respectively. The nanoparticles were further analysed for antimicrobial assays by well diffusion method against E. coli, S. aureus, P. aeruginosa, St. mutans and antifungal assay against the strains of C. albicans, A. niger and A. flavus. The highest zone of inhibition was observed against E.coli (1.7 cm) at a concentration of 400µg and maximum for C. albicans (2.5cm) at a concentration of 400µg. Microbial synthesized nanoparticles emerges as a promising medicine in curing different disorders because of its potent antioxidant and antimicrobial activity.

A rapid synthesis and antibacterial property of selenium nanoparticles using egg white lysozyme as a stabilizing agent

A simple method for the rapid synthesis of selenium nanoparticles (SeNPs) by the reduction of selenium dioxide using an aqueous egg white lysozyme solution (stabilizing agent) and ascorbic acid solution (reducing agent) has been described. The formation of SeNPs is assured by characterization with UV–Vis, FT-IR, XRD and morphological characters that were observed using TEM analyses. The absorbance of the SeNPs is found at 250 nm. The TEM images show that the SeNPs are uniform and in spherical shape of size 40–60 nm. The crystalline nature of SeNPs is assured by XRD analysis. The antibacterial property of synthesized SeNPs was tested against the pathogenic bacteria, i.e., Bacillus subtilis, Bacillus cereus, Escherichia coli, Staphylococcus pneumoniae, Proteus mirabilis and Klebsiella pneumoniae. SeNPs showed more antibacterial activity against B. subtilis (19 mm) and Streptococcus pneumoniae (15 mm) as compared with commercially available antibiotics such as streptomycin and erythromycin. The SeNPs synthesized via this process has proficient antimicrobial activity against pathogenic bacteria. SeNPs could play a significant role in pharmaceutical industries for the development of efficient antibiotic agents.

Synergistic effect of dietary selenium nanoparticles and riboflavin on the enhanced thermal efficiency of fish against multiple stress factors

An experiment was designed to delineate the efficacy of a dietary mixture of selenium nanoparticles (Se-NPs) and riboflavin (RF) on the thermal efficiency/tolerance of Pangasianodon hypophthalmus reared under arsenic (2.8 mg/L) and high-temperature (34 °C) stress. A green synthesis method was employed for the synthesis of Se-NPs using fish gills, which are normally discarded as by-products. Four isocaloric and iso-nitrogenous experimental diets were used, namely, a control diet (Se-NPs and RF @ 0 mg/kg diet) and diets containing RF @ 5, 10 or 15 mg/kg diet and Se-NPs @ 0.5 mg/kg diet, and feeding was performed for 95 days. At the end of the feeding trial, the thermal tolerance was evaluated by determination of the following parameters: critical thermal minimum (CTMin), lethal thermal minimum (LTMin), critical thermal maximum (CTMax), and lethal thermal maximum (LTMax). The anti-oxidative status in the form of catalase (CAT), glutathione-s-transferase (GST) and glutathione peroxidase (GPx) activities was significantly (p < 0.01) enhanced upon concurrent exposure to arsenic and high temperature at LTMin and LTMax, whereas a non-significant (p > 0.05) change in superoxide dismutase (SOD) activity was observed in the brain at LTMin and brain, gill and kidney at LTMax. Supplementation with Se-NPs @ 0.5 mg/kg diet and RF @ 5, 10 or 15 mg/kg diet significantly (p < 0.01) improved the anti-oxidative status with or without stressors. AChE activity in the brain was significantly (p < 0.01) inhibited upon concurrent exposure to arsenic and high temperature and improved in the treatment group supplemented with Se-NPs and RF. The arsenic concentration in muscle and experimental water and Se concentration in muscle and experimental feed were analysed. Overall, the results indicated that supplementation with RF @ 5 mg/kg diet and Se-NPs @ 0.5 mg/kg diet could confer protection to the fish against arsenic and thermal stress and led to enhanced thermal efficiency/tolerance of P. hypophthalmus.

Screening of cyanobacterial strains for the selenium nanoparticles synthesis and their anti-oxidant activity

Abstract Selenium (Se) is a crucial trace element required by all living organisms and its deficiency as well as excess is known to cause many diseases. Se substitutes when consumed in higher concentration cause toxicity. Therefore, research is now being focused to overcome the adverse effects of high Se doses. One possible way is to use them in form of Selenium nanoparticles (SeNPs). However, SeNPs synthesized through physical and chemical methods also show toxicity. Biologically synthesized SeNPs due to their lesser toxicity emerged as an alternative. Like plants, bacteria and other organisms, cyanobacterial extracts also have the ability to reduce the metal ions into nanoparticles due to the presence of many reducing biomolecules. The present study envisages screening of 20 cyanobacterial extracts for SeNPs synthesis based on time taken and particle size. The obtained synthesis time was in between two to five days and the range of SeNPs size was in between 11.8 to 60 nm. Synthesized SeNPs were characterized by UV–Vis spectroscopy, Scanning electron microscopy and Energy dispersive X-ray spectroscopy (EDX). Further, the anti-oxidant activities of best five cyanobacterial strains (Anabaena variabilis NCCU-441, Arthrospira indica SOSA-4, Gloeocapsa gelatinosa NCCU-430, Oscillatoria sp. NCCU-369, Phormidium sp. NCCU-104) were tested by the DPPH and SOR scavenging assays. The SeNPs synthesized by Arthrospira indica SOSA-4 showed the best anti-oxidant activity with IC50 = 81.67 ± 0.77 μg/ml (SOR) and 73.94 ± 1.53 μg/ml (DPPH).

Actinobacterial enzyme mediated synthesis of selenium nanoparticles for antibacterial, mosquito larvicidal and anthelminthic applications

Green chemistry approaches in nanotechnology have gained prominence nowadays. In the present study, Sodium Selenite was reduced to stable selenium nanoparticles by Streptomyces sp. (M10A65) isolated from magnesite soil samples of Salem district, Tamil Nadu, India. The selenium nanoparticles (Se-NPs) synthesis was enhanced by optimizing the enzyme production by adapting central composite design. The protein present in the crude culture filtrate was characterized and molecular weight of the enzyme was estimated to be ∼97 kDa. Actinobacterially synthesized Se-NPs (20–150 nm), were characterized by spectral, diffraction, microscopic studies and it exhibited good antibacterial, synergistic, larvicidal, and anthelminthic activity. The present study concludes that the extremophilic Streptomyces sp. M10A65 was the most suitable candidate for Se-NPs synthesis with diverse biological applications.