Stability Of Selenium Nanoparticles Research Articles

Comparative Study of Biosynthesizing Selenium Nanoparticles by Gum Arabic and Poly Anionic Cellulose to Prevent Radiation-Induced Death in Chinese Hamster Ovary (CHO) Cells

Purpose: In premenopausal women, abdominopelvic radiotherapy may have a direct and profound effect on ovarian function. Stabilized selenium Nanoparticles (NPs) with some natural materials have been demonstrated to have high antioxidant activity and reduce radiation damage as a radioprotector. This study was done to compare the ability for the biosynthesis of selenium NPs by Gum Arabic (Se-GA) and Polyanionic Cellulose (Se-PAC) in the protection of Chinese Hamster Ovary (CHO) cells against radiation damage.
 Materials and Methods: First, Selenium Nanoparticles (SeNPs) were synthesized in the presence of GA and PAC. Then, CHO cells were cultured in-vitro and were randomly divided into six groups in different concentrations of Se-GA and Se-PAC to measure the biocompatibility of NPs. Finally, cells were treated with NPs and radiation (6MV, 2Gy), and the percentage of cell survival was determined by MTT assay. Both NPs with an average size of 20-30 nm and an absorption absorbance peak at about 300 nm using Ultraviolet-Visible (UV–Vis) spectroscopy.
 Results: According to the parametric t-test analysis, Se-GA nanoparticles with a concentration higher than 0.4 ppm significantly increased the radioprotective effect on CHO cells compared to the control group (P<0.05). However, Se-PAC showed no significant increase in radioprotection in contrast to the control group (P>0.05).
 Conclusion: Se-GA nanoparticles have antioxidant properties, and the radiation protection properties of Se-GA nanoparticles are significantly higher than control. Consequently, Se-GA nanoparticles showed promising results and may be able to play the role of a radioprotector.

Study on the digestion and absorption property of Lycium barbarum polysaccharide-protein stabilized selenium nanoparticles from the perspective of stability in vitro

Digestion and absorption properties of selenium nanoparticles (SeNPs) stabilized by Lycium barbarum polysaccharide-protein conjugates (LBPP) were unclear. The digestive characteristics of selenium nanoparticles stabilized by Lycium barbarum polysaccharide-protein conjugates (LBPP-SeNPs) were explored through the simulation experiment in vitro. Besides, the transport and uptake mechanism of LBPP-SeNPs were thoroughly elucidated using the Caco-2 cell model. The size of LBPP-SeNPs increased from 115 nm to 280 nm after simulated gastrointestinal digestion, while the particle size of SeNPs changed more obviously and the boundary was more blurred. In digestion process, LBPP-SeNPs demonstrated a remarkably low selenium release (9%) after simulated gastrointestinal digestion, which indicated that LBPP-SeNPs possess great potential in the controlled release of selenium-enriched supplements. Moreover, the uptake and transport of LBPP-SeNPs were both energy- and concentration-dependent, and LBPP-SeNPs could mainly mediate the penetration of Caco-2 cells through endocytosis. Overall, LBPP-SeNPs were robust against gastrointestinal enzymes and a promising alternative for selenium delivery. The effective nano-carrier properties of LBPP-SeNPs underline their significant potential in the realm of pharmaceutical development and targeted therapy.

SYNTHESIS AND CHARACTERIZATION OF SELENIUM NANOPARTICLES STABILIZED WITH DIDECYLDIMETHYLAMMONIUM CHLORIDE

As part of this work, a synthesis procedure was developed and the characteristic of selenium nanoparticles stabilized with didecyldimethylammonium chloride (DDAC) was carried out. Nanoparticles were obtained by chemical reduction in an aqueous medium. Selenous acid was used as a selenium-containing precursor, ascorbic acid was used as a reducing agent, and didecyldimethylammonium chloride was used as a stabilizer. To determine the optimal parameters for the synthesis of selenium nanoparticles stabilized with didecyldimethylammonium chloride, a multifactorial experiment was carried out. The input parameters were the concentration of selenous acid, the concentration of didecyldimethylammonium chloride (DDAC) and the concentration of ascorbic acid. The average hydrodynamic radius of selenium particles, which was determined by the method of dynamic light scattering, was considered as an output parameter. The optimal parameters for the synthesis of selenium nanoparticles (R from 15 to 25 nm) have been established: reducing agent concentration – from 1.076 mol/l to 2.118 mol/l, stabilizer concentration – from 0.006 mol/l to 0.085 mol/l, precursor concentration – from 0.004 mol /l to 0.236 mol/l. At the next stage of research, the effect of solution pH on the average hydrodynamic radius of selenium nanoparticles was determined. It was shown that in the pH range from 1.81 to 2.21, the average hydrodynamic radius of selenium nanoparticles does not change significantly, which indicates the aggregative stability of selenium nanoparticles in this range. In the pH range from 2.21 to 4.56, there is a sharp increase in the average hydrodynamic radius from 21 to 497 nm. At pH ˃ 7.96, coagulation of selenium particles is observed.

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.

Synthesis, characterization, biological activity, and in vitro digestion of selenium nanoparticles stabilized by Antarctic ice microalgae polypeptide

A new type of uniformly dispersed selenium nanoparticles (SeNPs) was prepared using Antarctic ice microalgae polypeptides (AIMP) as the stabilizer and dispersant. Different characterization techniques and tests show that the SeNPs are effectively combined with AIMP through physical adsorption and hydrogen bonding to form a more stable structure. Orange-red, zero-valence, amorphous, and spherical AIMP-SeNPs with a diameter of 52.07 ± 1.011 nm and a zeta potential of −41.41 ± 0.882 mV were successfully prepared under the optimal conditions. The AIMP-SeNPs had significantly higher DPPH, ABTS and hydroxyl radicals scavenging abilities compared with AIMP and Na2SeO3, and prevented the growth of both Gram-negative and Gram-positive bacteria by disrupting the integrity of cell walls, cell membranes and mitochondrial membranes. The AIMP-SeNPs had higher gastrointestinal stability compared with SeNPs. Thus, this research highlights the crucial role of AIMP as a biopolymer framework in the dispersion, stabilization, and size management of SeNPs and concludes that AIMP-SeNPs can be exploited as a potent antioxidant supplement and antibacterial substance in foods and medicine.

Controlling the size, shape, and stability of SeNPs by bromelain: Improved antioxidant, anti-bacterial and anti-cancer activities

Selenium nanoparticles (SeNPs) are of great interest due to their pharmaceutical importance. We describe an advanced procedure to prepare highly stable SeNPs with controllable size by utilizing stem bromelain (BR) as a capping agent in a redox system of ascorbic acid and sodium selenite. We characterized the bromelain capped SeNPs by a number of complementary techniques including dynamic light scattering (DLS), fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX) analysis, circular dichroism (CD) and fluorescence spectroscopy. The mean dimensions of SeNPs and BR-SeNPs observed are 50.8 nm, 40.6 nm, and a Zeta potential of −14.6 and −4.37 were observed respectively. Further, we observed that bromelain concentration and temperature are critical factors in controlling the dimensions of BR-SeNPs. It was found that bromelain modified the biological activity of SeNPs. BR-SeNPs exhibited higher DPPH scavenging than SeNPs and bromelain. The anticancerous activity of the nanoparticles was studied in two human cancer cell lines, colorectal SW-480 and breast cancer MDA-MB-231. Colorectal carcinoma exhibited more sensitivity to BR-SeNPs (11.61 μg/mL). The normal cell line studies showed that the BR-SeNPs have low toxicity. When tested against four human pathogenic bacterial species (Bacillus subtilis, Pseudomonas aeruginosa, Staphylococcus aureus, and Xanthomonas oryzae), BR-SeNPs exhibited a zone of inhibition that was approx. two times wider, at 5 mm when compared to native bromelain. Our study offers new insight into how bromelain capping can tune the size, shape, and stability of SeNPs and provides new bases for using distinct proteins to engineer nanoparticles with enhanced anticancer, antibacterial, and antioxidant activities.

Photocatalytic degradation of dyes in aqueous media by gum shellac stabilized selenium nanoparticles

Abstract The present work outlines the successful synthesis of selenium nanoparticles (Se NPs) stabilized with gum shellac (GS) and their use as photocatalyst for the enhanced degradation of dyes. Se NPs were synthesized by a simple and cost effective chemical reduction method using selenious acid, GS and sodium borohydride. Gum shellac was used as stabilizing agent. The orange red gum shellac-selenium nanoparticles (GS–Se NPs) were characterized by UV–Vis spectroscopy, Fourier transform infra-red (FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The morphology of these particles appeared to be uniform and spherical as observed in SEM images. Energy dispersive X-ray spectroscopic profile showed the presence of elemental selenium, carbon and oxygen. The synthesized GS–Se NPs were investigated for their photo-catalytic efficiency towards degradation of methylene blue (MB) and methyl orange (MO) dye in aqueous media. Absorbance was measured at λ max 665 nm and 455 nm for MB and MO, respectively. Maximum degradation of MB in-comparison with MO obtained at 50 mg/L were 81.72 % and 71.42 % respectively. A very slow degradation rate was observed for the MO and MB in the absence of synthesized photocatalyst whereas greater percentage degradation was observed for the GS–Se NPs.

Synthesis, characterization and anti-inflammatory activity of selenium nanoparticles stabilized by aminated yeast glucan

Improving the dispersed stability of selenium nanoparticles (SeNPs) is the key to its application. In this study, yeast glucan with different degrees of amination (BNs) were used as stabilizers and capping agent to prepare dispersed SeNPs. The size, storage stability, and morphology of BNs/SeNPs were characterized. Results show that BNs/SeNPs presented positive potential and spherical morphologies with average particle size about 100–300 nm and kept stable at room temperature for a long time. The CCK-8 assay showed that BNs/SeNPs had significantly lower toxicity to RAW264.7 cells than SeNPs. Moreover, BNs/SeNPs could inhibit the generation of NO, IL-1β and IL-6 effectively in RAW 264.7 macrophages induced by LPS, and down-regulate the mRNA transcription of iNOS, IL-1β, IL-6 and chemokines (CCL2 and CCL5), indicating that BNs/SeNPs had good anti-inflammatory activity. Therefore, aminated yeast glucan could improve the stability and bioactivity of SeNPs simultaneously, which is a promising stabilizer for SeNPs.

Investigation of the Effect of Dispersion Medium Parameters on the Aggregative Stability of Selenium Nanoparticles Stabilized with Catamine AB.

This article presents the results of the synthesis of Se NPs stabilized by a quaternary ammonium compound-catamine AB. Se NPs were obtained by chemical reduction in an aqueous medium. In the first stage of this study, the method of synthesis of Se NPs was optimized by a multifactorial experiment. The radius of the obtained samples was studied by dynamic light scattering, and the electrokinetic potential was studied using acoustic and electroacoustic spectrometry. Subsequently, the samples were studied by transmission electron microscopy, and the analysis of the data showed that a bimodal distribution is observed in negatively charged particles, where one fraction is represented by spheres with a diameter of 45 nm, and the second by 1 to 10 nm. In turn, positive Se NPs have a diameter of about 70 nm. In the next stage, the influence of the active acidity of the medium on the stability of Se NPs was studied. An analysis of the obtained data showed that both sols of Se NPs exhibit aggregative stability in the pH range from 2 to 6, while an increase in pH to an alkaline medium is accompanied by a loss of particle stability. Next, we studied the effect of ionic strength on the aggregative stability of Se NPs sols. It was found that negatively charged ions have a significant effect on the particle size of the positive sol of Se NPs, while the particle size of the negative sol is affected by positively charged ions.

Pomegranate Peel Extract Stabilized Selenium Nanoparticles Synthesis: Promising Antimicrobial Potential, Antioxidant Activity, Biocompatibility, and Hemocompatibility.

The green synthesis of selenium nanoparticles (Se NPs) had been synthesized by pomegranate peel extract (PPE). The antimicrobial, antioxidant, and anticancer activities of the synthesized Se NPs, as well as their hemocompatibility, were investigated. Se NPs were characterized by UV-Vis., SEM, XRD, HR-TEM, DLS, EDX, FTIR, and mapping techniques. HR-TEM image represented the spheroidal forms with moderately monodispersed NPs with a mean diameter 14.5nm. The SEM image of Se NPs, incorporated with PPE, exhibits uniform NP surfaces, and the appearance was clear. The antimicrobial results confirmed the potential of Se NPs to hinder the growth of some tested pathogenic microbes. Results revealed that Se NPs exhibited promising antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus, and Streptococcus mutans where inhibition zones were 29, 16, 41, 22, and 54mm, respectively. Likewise, it exhibited antifungal activity where the values of inhibition zones were 41, 40, 38, and 36mm against Candida albicans, Cryptococcus neoformans, Aspergillus fumigatus, and A. niger, respectively. The antioxidant activities of Se NPs at concentrations 250-4000µg/mL were greater than 90% in all cases. Se NP concentrations of 500µg/mL or less are safe in usage according to hemocompatibility study. Se NPs had an IC50 of 113.73µg/mL in a cytotoxicity experiment. Results revealed that Se NPs have promising anticancer activities against MCF7 and Mg63 cancerous cell line, where IC50 was 69.8 and 47.9μg/mL, respectively. In conclusion, Se NPs were successfully biosynthesized using PPE for the first time; these Se NPs had promising antimicrobial, antioxidant, and anticancer activities.

Synthesis, characterization, and anticancer activity of protamine sulfate stabilized selenium nanoparticles

Selenium nanoparticles (SeNPs) have attracted much recent interest as nutraceuticals, while they face great challenges, such as poor stability and low cellular uptake efficiency. This study introduced a facile approach to synthesizing protamine sulfate (PS) functionalized selenium nanoparticles (PS-SeNPs) by using PS as a surface decorator. The monodisperse spherical PS-SeNPs with a particle size of 130 nm and a ζ-potential of +31 mV were ligated with PS through Se-N, Se-O bonds, and physical adsorption, which exhibits excellent physical stability against pH, temperature, and storage time. The positive surface charge of PS-SeNPs contributed to the enhancement of cellular uptake efficiency by endocytosis, which was 3-times higher than bare SeNPs. Compared to SeNPs (IC50 = 17.675 μg/mL), PS-SeNPs could dramatically inhibit the proliferation of HepG2 cells with an IC50 value of 5.507 μg/mL, as reflected by the induction of apoptosis, S phase arresting, overproduction of intracellular ROS, and depolarization of mitochondria membrane. Overall, these results demonstrated the great potential of PS-SeNPs that can be applied as a functional ingredient in foods and nutraceuticals.

Aggregation and stability of selenium nanoparticles: Complex roles of surface coating, electrolytes and natural organic matter

The application of selenium nanoparticles (SeNPs) as nanofertilizers may lead to the release of SeNPs into aquatic systems. However, the environmental behavior of SeNPs is rarely studied. In this study, using alginate-coated SeNPs (Alg-SeNPs) and polyvinyl alcohol-coated SeNPs (PVA-SeNPs) as models, we systematically investigated the aggregation and stability of SeNPs under various water conditions. PVA-SeNPs were highly stable in mono- and polyvalent electrolytes, probably due to the strong steric hindrance of the capping agent. Alg-SeNPs only suffered from a limited increase in size, even at 2500 mmol/L NaCl and 200 mmol/L MgCl2, while they underwent apparent aggregation in CaCl2 and LaCl3 solutions. The binding of Ca2+ and La3+ with the guluronic acid part in alginate induced the formation of cross-linking aggregates. Natural organic matter enhanced the stability of Alg-SeNPs in monovalent electrolytes, while accelerated the attachment of Alg-SeNPs in polyvalent electrolytes, due to the cation bridge effects. The long-term stability of SeNPs in natural water showed that the aggregation sizes of Alg-SeNPs and PVA-SeNPs increased to several hundreds of nanometers or above 10 µm after 30 days, implying that SeNPs may be suspended in the water column or further settle down, depending on the surrounding water chemistry. The study may contribute to the deep insight into the fate and mobility of SeNPs in the aquatic environment. The varying fate of SeNPs in different natural waters also suggests that the risks of SeNPs to organisms living in diverse depths in the aquatic compartment should be concerned.

SYNTHESIS AND PROPERTIES OF SELENIUM NANOPARTICLES IN NATURAL POLYSACCHARIDES MATRIX

Selenium nanoparticles were obtained by reduction of sodium selenite in aqueous solutions of nonstoichiometric alginate-chitosan polyelectrolyte complexes. Amorphous red nanosized selenium, formed as a result of the reaction, were characterized by maximum absorption at 256 nm. The process of formation and morphological characteristics of them were studied at different mass ratio of the components in the selenium-polysaccharide complex (in the range from 0.01 to 0.10). The morphological, dimensional, and spectral characteristics of obtained selenium nanoparticles were determined by transmission electron microscopy (TEM) and UV spectroscopy. The sample of nanoselenium was shown to consist of single nanoparticles, mostly spherical or partially elongated shapes, with an average size of 40 nm. The replacement of alginate (no more than 10%) with chitosan causes a significant increase in the stability of selenium nanoparticles, preventing them against aggregation and color change for three months. The biotoxicity of the synthesized nanoselenium was studied using Aliivibrio fischeri F1 bioluminescent assay. Selenium nanosamples were found to have no any inhibitory effect on bacterial bioluminescence and growth and thus have neither acute nor chronic biotoxicity. On contrary, sodium selenite, used for a comparison, decreased the bioluminescence of A. fischeri F1 at concentrations more than 100 mg/L. The values of NA2SeO3 half maximal effective concentration (EC50) were measured to be 420-820 mg/L at 15-60 minutes of incubation. Chronic biotoxicity of sodium selenite was manifested at concentrations more than 30 mg/L, and at 300 mg/L and higher led to a complete suppression of A. fischeri F1 growth and bioluminescence. Experimental study of biological properties of obtained selenium nanoparticles revealed an increase in seed germination and vigor of pea (Pisum sativum L.) of Madonna variety and barley (Hordeum vulgare L.) of Kuzen variety, as well as an increase in the dry matter mass of their roots and aerial parts. A high activity of growth processes for the studied crops was noted at a nanoselenium concentration of 20 mg/l.

Uniform and disperse selenium nanoparticles stabilized by inulin fructans from Codonopsis pilosula and their anti-hepatoma activities

The present work reported the extraction, purification and characterization of an inulin fructan from Codonopsis pilosula (CPW1) and its application in stabilization of selenium nanoparticles (SeNPs). The morphology, stability, and stabilization mechanism of CPW1 stabilized SeNPs (CPW1-Se) were explored, and the results showed that the SeNPs were amorphous state, with size of 54–79 nm, and kept stable within 15 days due to the interaction between SeNPs and the hydroxyl groups on the surface of CPW1. Moreover, the effects on proliferation and apoptosis of CPW1-Se to both normal cells (293T) and liver cancer cells (Huh-7 and HepG2) were evaluated systematically by using the CCK8 assay, plate clone formation assay, flow cytometry and western blot. The results indicated that CPW1-Se possessed selective anti-hepatoma activities without side effects on normal cells, which exhibited strong potential application in liver cancer treatments.

Digestion and absorption properties of Lycium barbarum polysaccharides stabilized selenium nanoparticles

In the present study, the digestion and absorption properties of Lycium barbarum polysaccharides stabilized selenium nanoparticles (LBP-SeNPs) were investigated. The results showed that selenium nanoparticles (SeNPs) exhibited a higher selenium release rate than LBP-SeNPs (p＜0.05) after being digested in the stages of oral cavity, stomach and intestine. During the digestion process, the particle size of the LBP-SeNPs and SeNPs were both significantly increased, but the particle size of LBP-SeNPs was significantly smaller than that of SeNPs. The results of TEM further indicated that LBP-SeNPs can better maintain the morphology and properties of nanoparticles. Besides, the experiments of the intestinal sac model showed that LBP-SeNPs can better promote the absorption of selenium in various parts (duodenum, jejunum and ileum) of the intestine. Therefore, the LBP can help to improve the structural stability of SeNPs in the digestion process and improve the bioavailability of selenium.

Selenium nanoparticles with photocatalytic properties synthesized by residual activated sludge

The treatment and disposal of residual activated sludge is a worldwide problem and the research on its reuse is still only in the earliest stages. Selenite is a toxic pollutant, while selenium nanoparticles (SeNPs) are environmentally friendly and have promising application prospects. At present, the reduction mechanism of selenite under the complex system is still poorly understood. In order to explore the mechanism of SeNPs synthesis by activated sludge resource utilization, SeNPs were synthesized by activated sludge extracts of domestic sewage (DSeNPs) and coking sewage (CSeNPs), respectively. The synthesis process, zeta potential and morphology size of SeNPs were changed by pH value, extract concentration and extract composition. Under the same synthesis conditions, the morphologies of DSeNPs and CSeNPs were mainly spherical and pseudo–spherical, while CSeNPs also contained pseudo-rod shape particles. The sizes and crystal grains of CSeNPs were smaller than those of DSeNPs. Compared with DSeNPs, a specific protein (~35 kDa) was found on the surface of CSeNPs using SDS-PAGE. By analyzing the fluorescence images of the two SeNPs, it was found that the relative contents of proteins, α-d-glucopyranose polysaccharides, and β-d-glucopyranose polysaccharides on their surfaces were obviously different (P < 0.05). The present study demonstrated that proteins, polysaccharides, humic-like and fulvic acid-like substances cooperated in the formation and stabilization of SeNPs. Furthermore, CSeNPs (bandgap: 1.68 eV) had more desirable photocatalytic performance than DSeNPs (bandgap: 1.84 eV). Under the light condition, CSeNPs could degrade Rhodamine B faster without adding hydrogen peroxide. This experiment provided a new insight into the resource utilization of activated sludge and a reference for the synthesis of nanometer selenium with excellent performance.

Synthesis, stability and anti-fatigue activity of selenium nanoparticles stabilized by Lycium barbarum polysaccharides

Lycium barbarum polysaccharides (LBP) with different molecular weights (LBP1, LBP2 and LBP3) of 92,441 Da, 7714 Da, and 3188 Da were used as stabilizers and capping agents to prepare uniformly dispersed selenium nanoparticles (SeNPs), and determined the storage stability. In addition, the anti-fatigue activity of LBP-decorated SeNPs with the best stability (LBP1-SeNPs) was estimated by using forced swimming test. The results showed that LBP1-SeNPs exhibited smaller particle size and more excellent stability than those of LBP2-SeNPs and LBP3-SeNPs when the storage time was extended to 30 days, and the average particle size was maintained at about 105.4 nm. The exhaustion swimming time of all tested dose groups of LBP1-SeNPs was significantly longer than the control group (p < 0.05), and the high-dose group among them was even obviously longer than the positive group (p < 0.05). The results of glycogen, blood urea nitrogen (BUN), blood lactic acid (BLA), superoxide dismutase (SOD), and malondialdehyde (MDA) levels were further confirmed that LBP1-SeNPs could relieve fatigue by increasing the reserve of glycogen, enhancing antioxidant enzyme levels and regulating metabolic mechanism. These results demonstrated that LBP1-SeNPs could be developed as a potential anti-fatigue nutritional supplement.

Highly stable selenium nanoparticles: Assembly and stabilization via flagellin FliC and porin OmpF in Rahnella aquatilis HX2

Microorganisms play a critical role in the reduction of the more toxic selenite and selenate to the less toxic elemental selenium. However, the assembly process and stability of selenium nanoparticles (SeNPs) remain understudied. The plant growth-promoting rhizobacterium Rahnella aquatilis HX2 can reduce selenite to biogenic SeNPs (BioSeNPs). Two main proteins, namely flagellin FliC and porin OmpF were identified in the BioSeNPs. The fliC and ompF gene mutation experiments demonstrated that the FliC and OmpF could control the assembly of BioSeNPs in vivo. At the same time, the expressed and purified FliC and OmpF could control the assembly of SeNPs in vitro. BioSeNPs produced by R. aquatilis HX2 exhibited high stability under various ionic strengths, while the chemically synthesized SeNPs (CheSeNPs) showed a high level of aggregation. The in vitro experiments verified that FliC and OmpF could prevent the aggregation of the CheSeNPs under various ionic strengths. This work reports the preparation of highly stable BioSeNPs produced by strain R. aquatilis HX2 and verifies that FliC and OmpF both could control the assembly and stability of BioSeNPs. BioSeNPs with high stability could be suitable as nutritional supplement to remedy selenium deficiency and in nanomedicine applications.

Chitosan-Stabilized Selenium Nanoparticles and Metformin Synergistically Rescue Testicular Oxidative Damage and Steroidogenesis-Related Genes Dysregulation in High-Fat Diet/Streptozotocin-Induced Diabetic Rats.

Background: this study examined the metformin (MF) and/or chitosan stabilized selenium nanoparticles (CH-SeNPs) efficacy to alleviate the male reproductive function impairment in a high-fat diet feed with low-dose streptozotocin (HFD/STZ) induced type 2 diabetes mellitus (T2DM) diabetic rat model. Methods: control non-diabetic, HFD/STZ diabetic, HFD/STZ+MF, HFD/STZ+CH-SeNPs, and HFD/STZ+MF+CH-SeNPs rat groups were used. After 60 days, semen evaluation, hormonal assay, enzymatic antioxidant, lipid peroxidation, testis histopathology, and the steroidogenesis-related genes mRNA expressions were assessed. Results: in the HFD/STZ diabetic rats, sperm count and motility, male sexual hormones, and testicular antioxidant enzymes were significantly reduced. However, sperm abnormalities and testicular malondialdehyde were significantly incremented. The steroidogenesis-related genes, including steroidogenic acute regulatory protein (StAr), cytochrome11A1 (CYP11A1), cytochrome17A1 (CYP17A1), and hydroxysteroid 17-beta dehydrogenase 3 (HSD17B3), and the mitochondrial biogenesis related genes, including peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGCα) and sirtuin (SIRT), were significantly downregulated in the HFD/STZ diabetic rats. However, CYP19A1mRNA expression was significantly upregulated. In contrast, MF and/or CH-SeNPs oral dosing significantly rescued the T2DM-induced sperm abnormalities, reduced sperm motility, diminished sexual hormones level, testicular oxidative damage, and steroidogenesis-related genes dysregulation. In the MF and CH-SeNP co-treated group, many of the estimated parameters differ considerably from single MF or CH-SeNPs treated groups. Conclusions: the MF and CH-SeNPs combined treatment could efficiently limit the diabetic complications largely than monotherapeutic approach and they could be considered a hopeful treatment option in the T2DM.

Physicochemical stability and functional properties of selenium nanoparticles stabilized by chitosan, carrageenan, and gum Arabic

To meet the increasing demand for polysaccharide-stabilized selenium nanoparticles (PS-Se°NPs) for industrial applications, in this study, we employed three commonly-used polysaccharides (i.e. chitosan (CS), carrageenan (Cg) and Gum Arabic (GA)) to fabricate Se°NPs, and compared their functional properties and their physicochemical stabilities, under varying conditions (ionic strength, pH, and temperature). The results showed that CS-Se°NPs had higher storage stability but easily aggregated in 500 mM NaCl or at pH > 8 because of their surface cationic groups. This, however, improved their DPPH free radical scavenging and antitumor activities. Compared to CS-Se°NPs, the anionic groups in Cg-Se°NPs increased their resistant to pH variations and reduced cellular toxicity, and the multi-branched structure of GA-Se°NPs increased their thermal stability. Overall, this study shows that the behaviors of PS-Se°NPs depends mainly on ionizable functional groups and the structure of polysaccharides, contributing to the development of PS-Se°NPs with applicability in the food and pharmaceutical industries.