Protective effect of starch-stabilized selenium nanoparticles against melamine-induced hepato-renal toxicity in male albino rats.

Melamine and its analogues are illegally added to raise the apparent protein content in foods. The elevated concentrations of these compounds cause adverse effects in humans and animals. In this contribution, the protective effects of the synthesized starch-stabilized selenium nanoparticles (Se-NPs@starch) on melamine-induced hepato-renal toxicity have been systematically investigated. The Se-NPs@starch were characterized by X-ray photoelectron spectroscopy (XPS) analysis, energy dispersive spectroscopy (EDS) mapping analysis, TEM, and FT-IR. Starch plays a crucial role in the stabilization and dispersion of Se NPs, as noticed from the TEM and EDS investigations. Furthermore, the atomic ratio of Se distribution over the starch surface is approximately 1.67%. The current study was conducted on four groups of adult male rats, and the oral daily treatments for 28 days were as follows: group I served as control, group II received Se-NPs@starch, group III was exposed to melamine, while group IV was treated with melamine and Se-NPs@starch. The results reveal a significant alteration in the histoarchitecture of both hepatic and renal tissues induced by melamine. Furthermore, elevated liver and kidney function markers, high malondialdehyde, and increased expression levels of apoptosis-related genes besides a reduction in GSH and expression levels of antioxidant genes were observed in the melamine-exposed group. Interestingly, the administration of the Se-NPs@starch resulted in remarkable protection of rats against melamine-induced toxicity through increasing the antioxidant capacity and inhibiting oxidative damage. Collectively, this study provides affordable starch-stabilized Se-NPs with potent biological activity, making them auspicious candidates for prospective biomedical applications.

The ameliorative effect of nanoselenium on histopathological and biochemical alterations induced by melamine toxicity on the brain of adult male albino rats.

Melamine is a chemical substance used as a food adulterant because of its high nitrogen content; it is known to induce neurotoxicity, thereby adversely affecting the central nervous system. The biocompatibility, bioavailability, lower toxicity, and the large surface area of nanosized selenium relative to its other forms indicate that selenium nanoparticles (SeNPs) have a potential ameliorative effect against melamine-induced neurotoxicity. In this study, we tested this hypothesis using 40 adult male albino rats that were randomly assigned into four groups (n = 10 per group): group I rats served as the untreated negative controls and were fed with standard diet and distilled water; group II rats were orally treated with melamine (300 mg/kg body weight/d); group III rats orally received melamine (300 mg/kg body weight/d) and SeNPs (2 mg/kg body weight/d); and group IV rats received SeNPs only (2 mg/kg body weight/d) for 28 days. Blood and brain samples were collected from all rats and processed for biochemical, histopathological, and immunohistochemical investigations. SeNPs were encapsulated in starch as a natural stabilizer and a size-controlling agent (SeNP@starch). The prepared SeNPs were characterized using different techniques. Inductively coupled plasma-optical emission spectrometry (ICP-OES) indicated that the percentage of selenium loaded in starch was 1.888 %. Powder x-ray diffractometer (XRD) was used to investigate the crystalline structure of the Se-NP@starch, to be tubular and composed of amorphous starch as well as metallic selenium. Thermogravimetric analysis confirmed the thermal stability of the product and determined the interactions among the different components. Transmission electron microscope demonstrated the spherical shape of SeNPs and their dispersion into starch surface as well as evaluating their size in nanoscale (range 20-140 nm). Our results revealed that the melamine- exposed rats had significantly elevated in malondialdehyde levels, significantly reduced in total antioxidant capacity, down-regulated expression of the antioxidant related genes Nrf2 (nuclear factor erythroid 2-related factor 2) and GPx (glutathione peroxidase), as well as up-regulated expression of the apoptosis-related gene Bax (B-cell lymphoma 2-associated X protein), with down regulation of Bcl-2 (B-cell lymphoma 2). Histopathological examination exhibited several alterations in the cerebrum, cerebellum, and hippocampus of the treated rats compared with the controls. Neuronal degeneration, vacuolation of the neuropils, and pericellular and perivascular spaces were observed. In addition, the pyramidal and granular cell layers of the hippocampus and cerebellum, respectively, were found to have significantly reduced thickness. Furthermore, a significant decrease in the percentage area of the glial fibrillary acidic protein and a significant increase in the percentage area of caspase-3 were noted. On the other hand, co-treatment with SeNPs partially ameliorated these alterations. A significant reduction in malondialdehyde levels; a non- significant elevation in total antioxidant capacity; up-regulation, upregulation of Nrf2, GPx, and Bcl-2 and downregulation of Bax were recorded. Neuronal degeneration, vacuolation of neuropils, and pericellular spaces were reduced. The pyramidal and granular cell layers restored their normal thickness. The percentage area of the glial fibrillary acidic protein significantly increased, whereas that of caspase-3 significantly decreased. In conclusion, SeNPs have an ameliorative effect against melamine-induced neurotoxicity in albino rats.

Distribution of essential heavy metals in the aquatic ecosystem of Lake Manzala, Egypt.

Lake Manzala is the largest and most productive lake of Egypt's northern coastal lakes and has socio-economic impacts. Pollution by heavy metals is the most significant type of pollution worldwide, particularly in Lake Manzala, which receives mixed discharges from densely populated areas. Water samples were collected at twelve sites around the lake in winter and summer of 2015. Samples of Eichhornia crassipes were collected in the winter, and Oreochromis niloticus samples were collected at two sites (8 and 10). V, Cr, Mn, Fe, Co, Ni, Cu, and Zn were analysed in these samples using inductively coupled plasma-mass spectrometry. The average metal concentrations were below the internationally accepted upper permissible limits and are improved compared to those in previous studies. However, the metal concentrations at the eastern and southeastern sites were higher than the allowable limits due to multiple waste discharges. Pollution assessment using pollution risk indicators indicated low to moderate concentrations of metal enrichment in the sediment and biota of the lake, except at sites near the eastern and southeastern drains; these latter sites were considered to be hazardous and should be taken into account in the current development efforts of the lake. Complete removal of floating plants transported by drains is recommended.

Adsorption of Methylene Blue and Pb2+ by using acid-activated Posidonia oceanica waste.

Dead leaves of seagrass Posidonia oceanica were activated by using one mol L-1 acetic acid and used as an eco-adsorbent for the removal of methylene blue (MB) and Pb2+ from aqueous solutions. The seagrass was characterized by chemical and physical measurements that confirmed the acid-activation of seagrass. The favourable conditions for MB and Pb2+ adsorption onto the activated seagrass (SGa) were determined to be a pH range of 2-12 and ≥6, an adsorbent dosage of 3.0 and 0.5 g L-1, respectively, and a shaking time of 30 min, which are suitable for a wide range of wastewaters. The equilibrium data were analysed using the Langmuir, Freundlich and Dubinin-Raduskavich-Kaganer (DRK) adsorption isotherm models. The Freundlich and DRK models best describe the adsorption processes of MB and Pb2+, on SGa with capacities of 2681.9 and 631.13 mg g-1, respectively. The adsorption isotherm fitting and thermodynamic studies suggest that the adsorption mechanism of MB may combine electrostatic and physical multilayer adsorption processes, in which MB may be present as monomers as well as dimers and trimers which were confirmed from UV spectroscopy whereas Pb2+ is chemically adsorbed onto SGa. The pseudo-2nd-order kinetic model was utilized to investigate the kinetics of adsorption processes. The removal process was successfully applied for MB-spiked brackish waste water from Manzala Lake, Egypt, with removal efficiencies of 91.5-99.9%.

Nano-sized selenium attenuates the developmental testicular toxicity induced by di-n-butyl phthalate in pre-pubertal male rats.

The current study was conducted to test the possible ameliorative role of selenium nanoparticles (Se-NPs) against oxidative damage of Leyding cells induced by di-n-butyl phthalate (DBP) in pre-pubertal male rat offspring. Forty-two pregnant female rats treated from gestation day (GD) 12 to postnatal day (PND) 14 day with two doses of Se-NPs (0.2 and 0.5 mg/kg/d) against developmental testicular toxicity induced by DBP (500 mg/kg/d). At PND 25 serum and testes of offspring were collected. Serum LH, the Leydig cells performance [total serum testosterone, LH and testosterone (LH/T) ratio, relative gene expression of insulin-like growth factor-3 (INSL3) and mineralocorticoid receptor (MR)], oxidative stress biomarker malondialdehyde (MDA) and antioxidant machinery [reduced glutathione (GSH), and the relative gene expression of antioxidant enzymes: superoxide dismutase (SOD), glutathione peroxidase (GPx)] were estimated in all groups. The obtained results revealed that maternal exposure to DBP significantly reduced total serum testosterone level, relative mRNA expression of INSL3 and MR genes with observed testicular damage revealed by increasing MDA and depressed levels of GSH and antioxidant enzymes. The histopathological changes include necrosis and desquamation of spermatogoneal cells. Co-administration of Se-NPs high dose along with DBP significantly increased serum testosterone, improved LH/T ratio and the relative mRNA expression of INSL3 and MR genes, decreased the level of MDA, and also improved all the antioxidant enzymes expression levels. In conclusion, Se-NPs could be a potent maternal prophylactic agent against the reduced total serum testosterone level and oxidative damage of Leydig cells induced by DBP via reducing the lipid peroxidation (LPO) and enhancing the antioxidant state in pre-pubertal male rat offspring.

Encapsulation of Biosynthesized Nanosilver in Silica Composites for Sustainable Antimicrobial Functionality.

Silver nanoparticles (AgNPs) have become known as a broad-spectrum antimicrobial agent. The antimicrobial activity of AgNPs is dependent on the particle size and the dispersion status. In this study, a simple and effective approach is developed for sequestering the biosynthesized AgNPs in silica composites during the gel formation of MCM-41. Composites with different Ag concentrations of 0.034% (Ag1@MCM-41), 0.151% (Ag2@MCM-41), and 0.369% (Ag3@MCM-41) are synthesized and then heated at 400 °C to produce Ag1@MCM-41H, Ag2@MCM-41H, and Ag3@MCM-41H, respectively. The samples are characterized by flame atomic absorption spectrometry, Fourier-transform infrared spectroscopy, X-ray diffraction, N2 physisorption, scanning electron microscopy, transmission electron microscopy, and thermogravimetric analysis. The AgNPs are confirmed to be highly dispersed in the amorphous silica framework. The antimicrobial activity of the AgNP-silica samples is investigated against Staphylococcus aureus, Escherichia coli, and Candida albicans using the cup-plate and the plate-count techniques. The results show an excellent antimicrobial effect of these samples against the studied microorganisms. Importantly, the AgNP-silica samples are found to be stable up to 58 months under ambient conditions. These stable and powerful antimicrobial composites provide a more practical and effective strategy for combating biomedical pathogens and public health threats.

Green Synthesis of Silver Nano-particles by Macrococcus bovicus and Its Immobilization onto Montmorillonite Clay for Antimicrobial Functionality.

Macrococcus bovicus was locally isolated from soil and used in the green synthesis of nano-scaling silver (NSAg). It was immobilized on a sodic-montmorillonite clay (MMT1) and cetyltrimethylammonium bromide-modified montmorillonite (MMT2) which was also calcined at 300 °C (MMT3). The NSAg clays were characterized by X-ray fluorescence, Fourier transform infrared spectra, X-ray diffractometry, surface area measurement, UV-Vis spectrometry, scanning electron microscope, transmission electron microscope and thermogravimetric analysis. NSAg was confirmed to be included in the interparticular cavities of the clay sheets and its mechanical stability was evidenced. The antimicrobial activity of the NSAg-modified clays was investigated against Staphylococcus aureus, Escherichia coli and Candida albicans using the cup plate and the plate count techniques. The antimicrobial activity of the NSAg clays was confirmed and attributed to the caging of NSAg in MMT cavities. MMT3 was found to inhibit the microbial growth to as high as 65 % as observed from the plate count method. Graphical Abstract Scheme of the biosynthesis of nano-scaling Ag and its immobilization and antimicrobial application.

Study of organically-modified montmorillonite clay for the removal of copper(II).

2-Oxyhydrazino-N-(2-methylen-yl-hydroxyphenyl)pyridinium (OMHP) ion was immobilized onto Na-montmorillonite clay (MMT). The modified clay (OMHP-MMT) was used for the removal of Cu(II). Experiments were carried out as a function of solution pH, stirring time, effect of some common ions and eluent type, concentration and volume. MMT, OMHP-MMT, and OMHP-MMT-loaded Cu(II) were characterized by X-ray diffractometry, electronic and infrared spectra, and elemental and thermogravimetric analyses. OMHP is suggested to be intercalated into MMT parallel to the aluminosilicate layers, with a capacity of 56.4 mEq/100g. OMHP-MMT shows good stability in 0.1-1 mol L(-1) hydrochloric or nitric acids, ammonia hydroxide, concentrated Na(+), K(+), NH(4)(+), Cl(-) or SO(4)(2-). It shows good removal efficiency and selectivity towards Cu(II) at pH 3.0-8.0 and stirring time 10 min with an removal capacity of 119 mEq/100g. Most common ions do not interfere with the removal process except Fe(3+). Extracted Cu(II) could be quantitatively recovered by 10 mL 1% thiourea in 0.1 mol L(-1) HCl with 100-fold preconcentration factor. OMHP-MMT was successfully applied to recover Cu(II) from different samples.

Immobilization of methylene blue onto bentonite and its application in the extraction of mercury (II).

Methylene blue was immobilized onto bentonite (BNT). The modified clay (MB-BNT) was used to extract Hg(2+) at pH 6.0 yielding Hg-MB-BNT. BNT, MB-BNT and Hg-MB-BNT were characterized by X-ray diffractometry, infrared spectra, and elemental and thermogravimetric analyses. MB is suggested to be intercalated into the major phase of BNT; montmorillonite mineral (MMT), lying parallel to the aluminosilicate layers, with a capacity of 36 mequiv./100g. MB-BNT shows good stability in 0.1-1M hydrochloric or nitric acids, ammonium hydroxide, and concentrated Na(+), K(+) or NH(4)(+) chlorides or iodides. It shows good selectivity towards Hg(2+) with an extraction capacity of 37 mequiv./100g in the presence of I(-) giving rise to a ratio of MB/Hg(2+)/I(-) 1:1:3 in the clay phase. Extracted Hg(2+) could be quantitatively recovered by ammonia buffer at pH 8.5. MB-BNT was successfully applied to recover Hg(2+) from spiked natural water and cinnabar mineral samples using the optimum conditions; pH 6.0, time of stirring 10 min and 10 mL of 0.05 M NH(4)Cl/NH(4)OH at pH 8.5 as eluent.

Synthesis and characterisation of morin-functionalised silica gel for the enrichment of some precious metal ions.

Silica gel was firstly functionalised with aminopropyltrimethoxysilane obtaining the aminopropylsilica gel (APSG). The APSG was reacted subsequently with morin yielding morin-bonded silica gel (morin-APSG). The structure was investigated and confirmed by elemental and thermogravimetric analyses, IR and (13)C NMR spectral studies. Morin-APSG was found to be highly stable in common organic solvents, acidic medium (<2molL(-1) HCl, HNO(3)) or alkaline medium up to pH 8. The separation and preconcentration of Ag(I), Au(III), Pd(II), Pt(II) and Rh(III) from aqueous medium using morin-APSG was studied. The optimum pH values for the separation of Ag(I), Au(III), Pd(II), Pt(II) and Rh(III) on the sorbent are 5.7, 2.2, 3.7, 3.7 and 6.8, giving rise to separation efficiencies of 43.9, 85.9, 97.7, 60.9 and 91.0%, respectively, where the activity was found to be >90% in the presence of acetate ion. The ion sorption capacity of morin-APSG towards Cu(II) at pH 5.5 was found to be 0.249mmolg(-1) where the sorption capacities of Ag(I) and Pd(II) were 0.087 and 0.121mmolg(-1) and 0.222 and 0.241mmolg(-1) at pH 2.2 and 5.7, respectively. This indicates a 1:1 and 1:2 morin/metal ratios at pH 2.2 and 5.7, respectively. Complete elution of the sorbed metal ions was carried out using 10mL (0.5molL(-1) HCl+0.01molL(-1) thiourea) in case of Au(III), Pd(II), Pt(II) and Rh(III) and 10mL 0.5molL(-1) HNO(3) in case of Ag(I). Morin-APSG was successfully employed in the separation and preconcentration of the investigated precious metal ions from some spiking water samples yielding 100-folds concentration factor. The relative standard deviation (R.S.D.) and the T-test (|t|(1)) were calculated.

A new selective chromogenic reagent for the spectrophotometric determination of thallium(I) and (III) and its separation using flotation and the solid-phase extraction on polyurethane foam.

A new sensitive chromogenic reagent, 9,10-phenanthaquinone monoethylthiosemicarbazone (PET), has been synthesized and used in the spectrophotometric determination of Tl(III). In HNO3, H2SO4 or H3PO4 acids, PET can react immediately at room temperature with Tl(III) to form a red 2:1 complex with a maximum absorption at 516 nm. The different analytical parameters affecting the extraction and determination processes have been examined. The calibration curve was found to be linear over the range 0.2-10 microg cm(-3) with a molar absorptivity of 2.2 x 10(4) dm3 mol(-1) cm(-1). Sandell's sensitivity was found to be 0.0093 microg cm(-2). No interference from macroamounts of foreign ions was detected, except for Pd(II). However, Pd(II) does not affect the determination process, because its complex with PET has its lambda(max) at 625 nm. The proposed method has been applied to the determination of Tl(I and III) in synthetic and natural samples after separation by flotation (in oleic acid/kerosene) and solid-phase extraction (on polyurethane foam) techniques. The two methods were found to be accurate and not subject to random error, but solid-phase extraction was preferred because it is cheap, simpler and there is no contamination risk coming from flotation reagents.

Controlled-pore silica glass modified with N-propylsalicylaldimine for the separation and preconcentration of trace Al(III), Ag(I) and Hg(II) in water samples.

Controlled-pore silica glass modified with N-propylsalicylaldimine (SCPSG) has been investigated as a surface-active matrix for the separation of some metal ions. The porous silica glass base was confirmed to have better stability towards hydrolysis in aqueous solution buffered at pH=9 in comparison to silica gel, which showed twice the surface area of controlled-pore silica glass. The different analytical parameters affecting the batch mode separation and preconcentration of trace Al(II), Ag(I) and Hg(II) in environmental samples using SCPSG, prior to their determination using inductively coupled plasma mass spectrometry (ICP-MS), were studied. The optimum conditions are pH 9.0 +/- 0.1, time of stirring 30 min and the eluent concentration 0.5 mol dm(-3) HNO3. The ion-exchange capacity of SCPSG with respect to Al(III), Ag(I) and Hg(II) was 0.27, 0.18 and 0.23 mmol g(-1), respectively. The recovery values for the metal ions were 96.8 +/- 0.86, 98.1 +/- 0.60 and 96.2 +/- 1.06%, and the analytical detection limits were 26.1, 1.49 and 0.44 pg cm(-3), respectively, for a preconcentration factor of 100. The method has been applied to the determination of the investigated metal ions in natural water samples as well as certified and reported samples and the results were found to be accurate.

Separation and preconcentration in a batch mode of Cd(II), Cr(III, VI), Cu(II), Mn(II, VII) and Pb(II) by solid-phase extraction by using of silica modified with N-propylsalicylaldimine.

The complexes formed between IE11 and Cd(II), Cr(III), Cu(II), Mn(II) and Pb(II) were identified and confirmed by IR, UV and pH-metric titration. The uptake behavior of porous silica modified with N-propylsalicylaldimine (IE11) and these metal ions were studied. Log k(d) was found to be within the range 2.19-5.16 depending on pH and time of stirring. IE11 was used in the separation and preconcentration of Cd(II), Cr(III, VI), Cu(II), Mn(II, VII) and Pb(II) from some natural water samples. Data were compared with those obtained by the solvent extraction method APDC/MIBK. The proposed methodology allows to verify an improvement in the water quality of Nile River probably attributed to high to moderate floods in the last few years. The method was found to be accurate and not subject to random error, i.e. precise.