Se Nanoparticles Research Articles

Selenium Hydride-Induced Oxidase-like Activity Inhibition of Amorphous/Crystalline Manganese Dioxide: Colorimetric Assay for Selenium Detection.

Hydride generation-based optical sensors have achieved on-site visual selenium (Se) determination with high anti-interference capability, yet they rely on the change of single-color intensity with a narrow linear dynamic range. Herein, we combined selenium hydride (H2Se)-induced activity inhibition of a manganese dioxide (MnO2) nanozyme with different degrees of 3,3',5,5'-tetramethylbenzidine (TMB) oxidation to realize sensitive multicolor visual detection of Se(IV). Due to its high oxidase-like (OXD-like) activity and sensitive response to H2Se, amorphous/crystalline manganese dioxide (ac-MnO2) was selected to form the headspace single droplet for microextraction and recognition. Via headspace redox reaction with H2Se, ac-MnO2 was reduced into low valence accompanied by in situ generation of Se nanoparticles, leading to the formation of a Se-MnOx aggregate. The experimental results and theoretical calculation indicated that, compared with MnO2, Se-MnOx had decreased active sites for adsorbing O2 to generate •O2-, resulting in the nanozyme activity inhibition that was totally dependent on Se(IV) concentration. The implementation of this strategy enabled accurate Se(IV) detection with a linear range from 10 to 600 μg L-1 and a limit of detection of 1.8 μg L-1. The portable smartphone-based detection for real sample analysis further demonstrated that this assay can be an easy, convenient, and intelligent tool for on-site selenium determination.

Selective and complementary antimicrobial and antiviral activity of silver, copper, and selenium nanoparticle suspensions in deep eutectic solvent

Metallic and nonmetallic nanoparticles are bioactive compounds that exhibit broad resistance to bacteria, fungi, and even viruses. In this paper, a deep eutectic solvent (DES) based on betaine, glucose, and ethylene glycol was used to obtain suspensions of silver, copper, and selenium nanoparticles. Depending on the nanoparticle precursor used, Ag, Cu, and Se nanoparticles (NPs) with an average particle size of 50−100 nm were prepared, and the properties of the products were confirmed by the STEM, XPS, DLS, and UV-VIS methods. The use of a DES, without the need for additional reactants, allowed the production of stable nanoparticles with increased bioactivity against microorganisms. The obtained systems showed high bioactivity against strains of S. aureus, E. coli, and C. albicans. Nanosuspensions, by generating reactive oxygen species (ROSs), caused enzyme inactivation and the inhibition of the metabolic processes of microorganisms. Particle-generated cell degradation processes were investigated through ROS generation assays, API assays, the determination of the MIC/MBC, and cell decomposition rate assays in the early logarithmic growth phase. Copper nanoparticles derived from copper(II) acetate were also highly active against the human influenza A/H1N1 viruses, human coronavirus (HCoV-OC43, Betacoronavirus 1), and vesicular stomatitis virus (VSV, Rhabdoviridae), showing a virus titer reduction of more than 93.7−99.96%.

Effect of vildagliptin conjugated monometallic nanoparticles and bimetallic nanocomposites on diabetes-induced cognitive deficit

Oxidative stress is one of the major causes of different metabolic disorders, including diabetes, cardiovascular diseases, neurodegenerative diseases and cancers. Some metabolic disorders like diabetes mellitus leads to secondary complications after micro and macrovascular complications. Some of the most prevalent neurodegenerative diseases, like cognitive impairment and Alzheimer's disease, are found in chronic diabetic patients. The present study is designed to understand the mechanism of interconnection between diabetes mellitus and cognitive deficit using the alloxan model of diabetes-induced cognitive deficit in the rat model. The alloxan monohydrate produces reactive oxygen species, producing superoxide free radicals, hydrogen peroxide and hydroxyl radicals. The hydroxyl radicals ultimately cause the death of beta cells, causing diabetes. Hence, the correlation of oxidative stress and neurodegeneration in cognitive impairment is the trigger for this study. In the present study, we investigate the ameliorative effect of vildagliptin (VLD) and its conjugated nanoparticles against alloxan-associated brain damage due to oxidative stress. The gold (Au), selenium (Se) nanoparticles, and bimetallic (Se@Au) nanocomposites of VLD are synthesized and assessed for improvement in their brain availability. The in-vitro antioxidant evaluation of the VLD and nanoparticles is done using DPPH, ABTS, and FRAP assay. The memory-related neurobehavioral studies, in-vivo antioxidant studies, in-vivo biochemical studies, and histopathological examinations are evaluated in rat brains. The VLD and its nanoformulations exhibited in-vitro and in-vivo antioxidant properties significantly (p < 0.01). They reduced the activity of AChE and nitrite in the alloxan diabetic rats. The bimetallic Se@Au VLDNCs displayed a more protective effect than VLD, VLD–AuNPs, and VLD–SeNPs.

C3N4/Se-CNTs as Advanced Metal-Free Catalysts for the Photoassisted Electrocatalytic Oxygen Evolution Reaction.

Photoassisted electrocatalysis is a frontier direction of electrocatalysis for promoting energy conversion. In this work, a metal-free C3N4/Se-CNTs is reported as a novel catalyst for photoassisted electrocatalytic oxygen evolution reaction (OER). C3N4 has an appropriate bandgap, high specific surface area, and long-term stability. CNTs can modulate the electronic environment of C3N4 by strong π-π interaction and greatly enhance the separation efficiency of photogenerated carriers. The distributed Se nanoparticles in CNTs can further increase the charge transfer ability. As a metal-free catalyst, the C3N4/Se-CNTs exhibits an overpotential of 231 mV at a current density of 10 mA cm-2 and a small Tafel slope of 52 mV dec-1 under illumination, which ranks among the best catalysts for photoassisted OER performance, surpassing most noble and transition metal-based catalysts. The result demonstrates the great potential of C3N4-based catalysts in the photoassisted OER process and provides a new perspective to explore the excellent metal-free OER catalysts.

Study of Cytotoxicity of Selenium Nanoparticles Synthesized Using Artificial Metal-Binding Tumor-Specific Protein W8-3C

For the first time, the pW8-3C construct encoding the artificial tumor-specific protein W8-3C with the addition of 3 residues of free Cys at the C end was created and described. Using purified W8-3C protein, dispersions of nanoparticles 75.24 nm in diameter at polydispersity index (Pdi) of 0.064 and Se content of 1566 µg/mL were obtained and characterized for the first time. The dispersions remained stable upon storage for 6 months at +4°C. For comparison, the maximum Se content in the nanoparticle dispersion obtained in the presence of W8-3C protein and Pluronic F-127 was 399 µg/ml. The cytotoxic activity of the obtained nanoparticles was studied on transplanted cells of human tumor lines: HeLa (cervical carcinoma), U-87 MG (glioblastoma), MCF-7 (breast carcinoma) and HCT-116 (colon carcinoma) and compared with that on the diploid human fibroblast line WI-38 in vitro. It was shown that the IC50 of Se nanoparticles obtained using the W8-3C protein for tumor lines ranged from 5.25 to 8.37 µg/ml, while the IC50 for normal fibroblasts was 14.3 µg/ml (difference in values by a factor of 1.7–2.7 times).

Mannose coated selenium nanoparticles normalize intestinal homeostasis in mice and mitigate colitis by inhibiting NF-κB activation and enhancing glutathione peroxidase expression

Impaired intestinal homeostasis is a major pathological feature of inflammatory bowel diseases (IBD). Mannose and selenium (Se) both demonstrate potential anti-inflammatory and anti-oxidative properties. However, most lectin receptors bind free monosaccharide ligands with relatively low affinity and most Se species induce side effects beyond a very narrow range of dosage. This has contributed to a poorly explored therapies for IBD that combine mannose and Se to target intestinal epithelial cells (IECs) for normalization gut homeostasis. Herein, a facile and safe strategy for ulcerative colitis (UC) treatment was developed using optimized, mannose-functionalized Se nanoparticles (M-SeNPs) encapsulated within a colon-targeted hydrogel delivery system containing alginate (SA) and chitosan (CS). This biocompatible nanosystem was efficiently taken up by IECs and led to increased expression of Se-dependent glutathione peroxidases (GPXs), thereby modulating IECs’ immune response. Using a mouse model of DSS-induced colitis, (CS/SA)-embedding M-SeNPs (C/S-MSe) were found to mitigate oxidative stress and inflammation through the inhibition of the NF-kB pathway in the colon. This stabilized mucosal homeostasis of IECs and ameliorated colitis-related symptoms, thereby providing a potential new approach for treatment of IBD.

Coupling (NixCo1-x)0.85Se with N-doped MoSe2 for hybrid supercapacitors with remarkable cyclic durability

Despite being a novel supercapacitive material, the widespread application of layered molybdenum diselenide has been hindered by its low specific capacity, significant volume changes during electrochemical reactions, and slow kinetics. In this study, we successfully combined (NixCo1-x)0.85Se nanoparticles with N-MoSe2 to create (NixCo1-x)0.85Se/N-MoSe2 hybrids (labeled as AxB1-xC). The electrochemical performance of AxB1-xC was dramatically improved due to the synergistic effects between nickel and cobalt, as well as between (NixCo1-x)0.85Se and N-MoSe2. Among the various AxB1-xC electrodes, the A0.8B0.2C electrode exhibited the best electrochemical performance when the Ni/Co ratio was 0.8/0.2. It provided a specific capacity of 397.9 C g−1 at 0.5 A/g and retained 220.0 C g−1 after 2,000 cycles at 10 A/g. Furthermore, we constructed an A0.8B0.2C//AC hybrid supercapacitor to assess its energy storage capability. The A0.8B0.2C//AC device achieved a specific capacitance of 72.6 F g−1 at 0.5 A/g with an energy density of 25.8 Wh kg−1 at 400 W kg−1. The capacitive retention of the A0.8B0.2C//AC device was 92.9 % after 40,000 cycles at 3 A/g. Impressively, a self-constructed A0.8B0.2C//AC device could power a timer for about 24 min, demonstrating its potential for practical applications.

Silicon dioxide and selenium nanoparticles enhance vase life and physiological quality in black magic roses

In contemporary floriculture, particularly within the cut flower industry, there is a burgeoning interest in innovative methodologies aimed at enhancing the aesthetic appeal and prolonging the postharvest longevity of floral specimens. Within this context, the application of nanotechnology, specifically the utilization of silicon and selenium nanoparticles, has emerged as a promising approach for augmenting the qualitative attributes and extending the vase life of cut roses. This study evaluated the impact of silicon dioxide (SiO2-NPs) and selenium nanoparticles (Se-NPs) in preservative solutions on the physio-chemical properties of ‘Black Magic’ roses. Preservative solutions were formulated with varying concentrations of SiO2-NPs (25 and 50 mg L−1) and Se-NPs (10 and 20 mg L−1), supplemented with a continuous treatment of 3% sucrose. Roses treated with 20 mg L−1 Se-NPs exhibited the lowest relative water loss, highest solution uptake, maximum photochemical performance of PSII (Fv/Fm), and elevated antioxidative enzyme activities. The upward trajectory of hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels in petals was mitigated by different levels of SiO2 and Se-NPs, with the lowest H2O2 and MDA observed in preservatives containing 50 mg L−1 SiO2- and 20 mg L−1 Se-NPs at the 15th day, surpassing controls and other treatments. Extended vase life and a substantial enhancement in antioxidative capacity were noted under Se and Si nanoparticles in preservatives. The levels of total phenols, flavonoids, and anthocyanin increased during the vase period, particularly in the 50 and 20 mg L−1 Se-NPs and SiO2-NPs. Petal carbohydrate exhibited a declining trend throughout the longevity, with reductions of 8% and 66% observed in 20 mg L−1 Se-NPs and controls, respectively. The longest vase life was achieved with Se-NPs (20 mg L−1), followed by SiO2-NPs (50 mg L−1) up to 16.6 and 15th days, respectively. These findings highlight the significant potential of SiO2- and Se-NPs in enhancing the vase life and physiological qualities of ‘Black Magic’ roses, with SiO2-NPs showing broad-spectrum efficacy.

Biosynthesis of selenium nanoparticles as a potential therapeutic agent in breast cancer: G2/M arrest and apoptosis induction

The drawbacks and adverse reactions of conventional breast cancer (BC) medications have prompted researchers to seek novel therapeutic approaches. This study aimed to study the impact of biosynthesized selenium nanoparticles by yeast on breast cancer (MCF-7) cells and to find potential underlying mechanisms. Therefore, marine yeast isolates were screened for their ability to biosynthesis selenium nanoparticles (SeNPs). The most potent isolate was identified as Candida pseudojiufengensis based on 18 S rRNA gene sequencing. Incubation of cell-free extract with 0.8mM of SeO2 for 48h at 40°C in pH of 7.0 were optimal conditions for the biosynthesis of SeNPs. The biosynthesized SeNPs were characterized by UV–Vis spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and dynamic light scattering (DLS) measurements including average particle size distribution and average zeta potential. The results showed that the biosynthesized SeNPs displayed a maximum absorbance peak in the UV-Vis spectrum at 560nm due to surface plasmon resonance. TEM image elevated spherical shape particles with an average size of 12nm. SRB assay, flow cytometry, and other biochemical methods were employed to assess SeNPs anti-proliferative effects on MCF-7 cells. SeNPs showed superior anticancer efficacy against MCF-7 cells compared to colon (HCT-116) and liver (HepG2) cancer cells, as evidenced by lower IC50 values (19.59µg/ml) against 36.36µg/ml and 27.81 ±1.4µg/ml, respectively. However, SeNPs demonstrated no cytotoxic effects against HSF cells. Moreover, treatment with SeNPs induces G2/M arrest along with triggering apoptosis in MCF-7 cells. Furthermore, MCF-7 cells treated with SeNPs showed increased oxidative stress, as indicated by observable rises in LPO and 8-OHDG, accompanied by considerable exhaustion in antioxidant enzyme activity. These findings demonstrated that Se nanoparticles synthesized from yeast have therapeutic promise in BC treatment.

Foliar application of microbial nano-selenium enhances selenium uptake and alleviates oxidative stress

Selenium (Se) is an essential micronutrient to humans and animals in diet primarily from edible crops. However, limited studies have been conducted on applying microbially synthesized Se nanoparticles (BioSeNPs) to affect plant Se uptake and toxicity. The bacterium Bacillus wiedmannii ES2–45 was able to efficiently produce BioSeNPs by completely reducing 5 mM selenite [Se(IV)] within 24 h. Then, fermented BioSeNPs were sprayed on the leaf surface of Brassica rapa L to investigate their effects on growth and Se accumulation. Total Se and leaf biomass increased significantly by 124 % and 14.3 % respectively in the BioSeNP treatment compared to the Se(IV) treatment. The Se(VI) treatment was found to be toxic to the leaves although Se(VI) had similar effects to BioSeNP treatments. Notably, BioSeNP treatment significantly increased the plant’s ability to alleviate oxidative stress including levels of chlorophyll, malonaldehyde (MDA), and catalase (CAT) (P<0.05). In conclusion, the foliar application of BioSeNPs is a promising strategy to improve the Se content of vegetables and alleviate Se-induced oxidative stress.

Characterization and subcellular localization of selenium in Limosilactobacillus fermentum Ln-9 obtained by intense pulsed light-ultraviolet combined mutagenesis

Lactic acid bacteria (LAB) can convert inorganic selenium (Se) to organic Se and elemental forms with low toxicity and high bioavailability, but a comprehensive Se analysis of Se-enriched LAB is lacking. In this study, Limosilactobacillus fermentum Ln-9 was obtained by intense pulsed light-ultraviolet combined mutagenesis, and its characteristics and subcellular localization of Se were analyzed. The results displayed that Ln-9 accumulated 3.03 times Se that of the original strain. Under optimal fermentation conditions, the total Se content of Se-enriched Ln-9 (SeLn-9) reached 12.16 mg/g with 96.34% contained in Se nanoparticles (SeNPs), which was much higher than that of organic macromolecules. Furthermore, SeNPs were mainly localized outside the cell, Se-proteins were in the membrane and cytoplasmic fractions, and Se-polysaccharides were in the membrane fraction. Besides, SeLn-9 maintained a good morphology and gastrointestinal tolerance and had an enhanced antioxidant capacity. These findings make Ln-9 promising for applications in the food industry.

Se-functionalized ZIF-8 nanoparticles: synthesis, characterization and disruption of biofilms and quorum sensing in Serratia marcescens

The majority of research on nanomaterials has been concentrated on metal nanoparticles since they are easily made and manipulated. Nanomaterials have shown a wide range of applications in biology. Nevertheless, their bioactivity declines due to their extreme susceptibility to and novel Se@ZIF-8 by chemical method. The sizes and morphologies of Se (0) and Se@ZIFchemical and physical stimuli. The goal of encapsulating these nanomaterials in a matrix is gradually being pursued, which boosts their affordability, stability, and usability. Metal-organic frameworks, often known as MOFs, have the potential to be the best platforms for encapsulating metal nanoparticles due to their well-defined frameworks, persistent porosity, and flexibility in modification. In this investigation, we report the synthesis and optimization of polyvinylpyrrolidone-stabilized Se(0) nanoparticles -8 were affected by the ratios of Se/Zn2+and [hmim]/Zn2+used. The optimized Se@ZIF-8 nanoparticles exhibited a particle size and zeta potential of 319 nm and -34 mv respectively. Transmission electron microscopy displayed spherical morphology for Se(0) nanoparticles, whereas the surface morphology of novel Se@ZIF-8 nanoparticles was drastically changed to hexagonal shaped structures with smooth surface morphologies in scanning electron microscopy (SEM). The DTA, TG/DTG, XRD analysis confirmed the presence of novel Se incorporated ZIF-8 nanoparticulate framework. The synthesized novel Se@ZIF-8 nanoparticles showed efficient antibacterial activity as evidenced by low MIC values. Interestingly, these Se@ZIF-8 NPs not only inhibited biofilm formation inS. marcescens,but also effectively eradicated mature biofilms by degrading the eDNA of the EPS layer. It was validated by confocal laser scanning microscopy and SEM analysis. It was observed that Se@ZIF-8 targeted the Quroum Sensing pathway and reduced its associated virulence factors production. This work opens up a different approach of Se@ZIF-8 nanoparticles as novel antibiotics to treat biofilm-associated infections caused byS. marcescensand offer a solution for antimicrobial resistance.

Promising antagonistic effect of bimetallic silver-selenium nanoparticles against Ralstonia solanacearum-causing wilt disease in eggplant (Solanum melongena L.)

Ralstonia solanacearum wilt disease causes significant economic losses to a number of crops worldwide, including eggplant (Solanum melongena L.). In this article plant growth promotions such as silver (Ag) nanoparticles (NPs), selenium (Se) NPs, and bimetallic Ag-Se NPs were used to combat the Ralstonia solanacearum wilt (RSW) disease and encourage growth-promoting strategies and resistance mechanisms in Solanum melongena L. Results clarified that the tested nano inducers against R. solanacearum (RS) have beneficial antibacterial. Bimetallic Ag-Se NPs (100 μg/mL) was the best treatment in reducing disease index (DI) by 17.5 and increasing the protection by 78.1 %, then Ag NPs and Se NPs, where the DI was 30 and 32.5 and protection by 62.5 % and 59.4 %, respectively. The potential resistance of developing eggplant plants was assessed using morphological characteristics, photosynthetic pigments, soluble carbohydrates, soluble protein, antioxidant enzyme activity, and isozymes. There was an increase in vegetative growth, photosynthetic pigments, soluble carbohydrates, and proteins in infected plants treated with all tested inducers, especially, bimetallic Ag-Se NPs. The amount of phenol content and the activity of antioxidant enzymes (PPO and POD) across diseased and healthy plants were recorded after applying all investigated inducers. The commercial use of a combination of tailored bimetallic Ag-Se NPs as nutritional therapy against R. solanacearum may be advised.

Genotoxic effect of selenium arabinogalactan nanocomposite on nucleated blood cells

Introduction. Selenium (Se) nanoparticles have attracted the interest of researchers for various applications due to their unusual properties. Despite their advantages, Se nanoparticles also have toxic effects, so for their successful use it is necessary to know the doses that are safe for the use. An important component in the development of pathological processes is the occurrence of DNA damage after exposure to Se nanoparticles, which can lead to severe disorders. Materials and methods. Male white rats were orally administered a solution of Se nanocomposite at a dose of 500 μg/kg for 10 days. The genotoxicity of the nanocomposite under study was assessed by the occurrence of DNA damage in blood cells using the DNA comet method in the alkaline version. The results were obtained during 2 stages: one day after exposure and after 4 months to identify the persistence or absence of a negative effect. Results. With using the DNA comet method, intragastric administration of Se nanocomposite was found to cause the damage to the DNA structure, and this effect persists not only 24 hours after exposure, but also 4 months later. Limitations. The study is limited to the study of DNA fragmentation on the next day after a 10-day exposure to Se nanocomposite in male white rats and during the long-term period after 4 months. Conclusion. The study revealed persistent DNA damage in the nucleated blood cells of male albino rats, which apparently may be associated with the main mechanism of Se toxicity: nonspecific replacement of sulfur in sulfur-containing amino acids. However, the toxic effects of the nanocomposite may also be caused by its pro-oxidant properties, which requires further confirmation.

Biometabolically Derived Selenium Nanoparticles Armed with Protein Protective Suit toward High-Performance Li-Se Batteries.

Selenium (Se) serves as a burgeoning high-energy-density cathode material in lithium-ion batteries. However, the development of Se cathode is strictly limited by low Se utilization and inferior cycling stability arising from intrinsic volume expansion and notorious shuttle effect. Herein, a microbial metabolism strategy is developed to prepare "functional vesicle-like" Se globules via Bacillus subtilis subsp. from selenite in sewage, in which Se nanoparticles are armed with a natural biological protein membrane with rich nitrogen and phosphorus, achieving the eco-efficient conversion of trash into treasure (selenite, SeO3 2- → Selenium, Se). The appealing-design "functional vesicle-like" Se globules are beneficial to accommodate volume changes of Se in electrochemical reactions, confining polyselenides via chemisorption, and enhancing mechanical strength of electrode by associated bacteria debris, realizing comprehensive utilization of microorganism. By conceptualizing "functional vesicle-like" Se globules, rather than artificial Se-host composites, as cathode for lithium-selenium batteries, it exhibits outstanding cycling stability and improved rate performance. This strategy opens the door to design smart electrode materials with unattainable structure that cannot be achieved by traditional approaches, achieving eco-efficient conversion of pollutants into energy-storage nanomaterials, which will be a promising research field for interdisciplinary of energy, biology, and environment.

Identification of a multi-modal mechanism for Se(VI) reduction and Se(0) allotropic transition by Stenotrophomonas bentonitica.

Microorganisms can play a key role in selenium (Se) bioremediation and the fabrication of Se-based nanomaterials by reducing toxic forms (Se(VI) and Se(IV)) into Se(0). In recent years, omics have become a useful tool in understanding the metabolic pathways involved in the reduction process. This paper aims to elucidate the specific molecular mechanisms involved in Se(VI) reduction by the bacterium Stenotrophomonas bentonitica. Both cytoplasmic and membrane fractions were able to reduce Se(VI) to Se(0) nanoparticles (NPs) with different morphologies (nanospheres and nanorods) and allotropes (amorphous, monoclinic, and trigonal). Proteomic analyses indicated an adaptive response against Se(VI) through the alteration of several metabolic pathways including those related to energy acquisition, synthesis of proteins and nucleic acids, and transport systems. Whilst the thioredoxin system and the Painter reactions were identified to play a crucial role in Se reduction, flagellin may also be involved in the allotropic transformation of Se. These findings suggest a multi-modal reduction mechanism is involved, providing new insights for developing novel strategies in bioremediation and nanoparticle synthesis for the recovery of critical materials within the concept of circular economy.

Anti-hepatoma immunotherapy of Pholiota adiposa polysaccharide-coated selenium nanoparticles by reversing M2-like tumor-associated macrophage polarization

Targeting macrophages to regulate the tumor microenvironment is a promising strategy for treating cancer. This study developed a stable nano drug (PAP-SeNPs) using Se nanoparticles (SeNPs) and the Pholiota adiposa polysaccharide component (PAP-1a) and reported their physical stability, M2-like macrophages targeting efficacy and anti-hepatoma immunotherapy potential, as well as their molecular mechanisms. Furthermore, the zero-valent and well-dispersed spherical PAP-SeNPs were also successfully synthesized with an average size of 55.84 nm and a negative ζ-potential of −51.45 mV. Moreover, it was observed that the prepared PAP-SeNPs were stable for 28 days at 4 °C. Intravital imaging highlighted that PAP-SeNPs had the dual effect of targeting desirable immune organs and tumors. In vitro analyses showed that the PAP-SeNPs polarized M2-like macrophages towards the M1 phenotype to induce hepatoma cell death, triggered by the time-dependent lysosomal endocytosis in macrophages. Mechanistically, PAP-SeNPs significantly activated the Tlr4/Myd88/NF-κB axis to transform tumor-promoting macrophages into tumor-inhibiting macrophages and successfully initiated antitumor immunotherapy. Furthermore, PAP-SeNPs also enhanced CD3+CD4+ T cells and CD3+CD8+ T cells, thereby further stimulating anti-hepatoma immune responses. These results suggest that the developed PAP-SeNPs is a promising immunostimulant that can assist hepatoma therapy.

Synthesis and Superficial Modification "In Situ" of Copper Selenide (Cu2-x Se) Nanoparticles and Their Antibacterial Activity.

Copper selenide nanoparticles (Cu2-x Se NPs) have received a lot of attention in recent decades due to their interesting properties and potential applications in various areas such as electronics, health, solar cells, etc. In this study, details of the synthesis and characterization of copper selenide nanoparticles modified with gum arabic (GA) are reported. Also, through transmission electronic microscopy (TEM) analysis, the transformation of the morphology and particle size of copper selenide nanoparticles in aqueous solution was studied. In addition, we present an antimicrobial study with different microorganisms such as Staphylococcus aureus (S. aureus), Escherichia coli (E. coli) and Candida albiacans (C. albicans). Copper selenide nanoparticles were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry analysis (DSC) and TEM. XRD confirmed the crystal-line structure of the nanoparticles such as cubic berzelanite with a particle size of 6 nm ± 0.5. FTIR and TGA corroborated the surface modification of copper selenide nanoparticles with gum arabic, and DSC suggested a change in the structural phase from cubic to hexagonal. TEM analysis demonstrated that the surface modification of the Cu2-x Se NPs stabilized the nanostructure of the particles, preventing changes in the morphology and particle size. The antimicrobial susceptibility analysis of copper selenide nanoparticles indicated that they have the ability to inhibit the microbial growth of Staphylococcus aureus, Escherichia coli and Candida albicans.

Ionomic Profile of Rice Seedlings after Foliar Application of Selenium Nanoparticles.

Nanotechnology has been increasingly used in plant sciences, with engineered nanoparticles showing promising results as fertilizers or pesticides. The present study compared the effects in the foliar application of Se nanoparticles (SeNPs) or sodium selenite-Se(IV) on rice seedlings. The degree of plant growth, photosynthetic pigment content, and concentrations of Se, Na, Mg, K, Ca, Mn, Co, Cu, Zn, As, Cd, and Pb were evaluated. The results showed that the application of SeNPs at high concentrations (5 mg L-1), as well as the application of Se(IV), inhibited plant growth and increased the root concentrations of As and Pb. The application of SeNPs at 0.5 mg L-1 significantly increased Se accumulation in the aerial part from 0.161 ± 0.028 mg kg-1 to 0.836 ± 0.097 mg kg-1 without influencing physiological, chemical, or biochemical parameters. When applied to leaves, SeNPs tended to remain in the aerial part, while the application of Se(IV) caused a higher Se translocation from the shoots to the roots. This study provides useful information concerning the uptake, accumulation, and translocation of different Se formulations in rice seedlings and their effect on plant ionomic profiles, thus showing that the foliar application of SeNPs at low concentrations can be an effective and safe alternative for rice biofortification.

Biosynthetic MnSe nanobomb with low Mn content activates the cGAS-STING pathway and induces immunogenic cell death to enhance antitumour immunity

Triple-negative breast cancer (TNBC) is a relatively “cold” tumour with low immunogenicity compared to other tumour types. Especially, the immune checkpoint inhibitors to treat metastatic TNBC only shows the modest immune response rates. Here, we used Chlorella vulgaris as a bioreactor to synthesize an efficient nanobomb (Bio-MnSe) aimed at eliciting systemic anti-tumour immune response. Despite possessing extremely low Mn content, Bio-MnSe effectively produced more ROS and activated stronger cGAS-STING signal pathway compared to pure Se nanoparticles and free Mn2+ ions, promoting the infiltration of natural killer (NK) cells, cytotoxic T lymphocytes (CTLs) in tumour, effectively turning “cold” tumour into “hot” tumour, and achieving strong antitumour immunotherapy. Additionally, the use of αPD-L1 as an immune checkpoint antagonist further increased the anti-tumour immune response of Bio-MnSe, resulting in enhanced anti-tumour effects. Doxorubicin (Dox), an immunogenic cell death (ICD) inducer, was combined with Bio-MnSe to form Bio-MnSe@Dox. This Bio-MnSe@Dox not only directly damaged tumour cells and induced tumour ICD but also promoted dendritic cell maturation, cytotoxic T lymphocyte infiltration, and NK cell recruitment, synergistically intensifying anti-tumour immune responses and suppressing tumour relapse and lung metastasis. Collectively, our findings propose an effective strategy for transforming ‘cold’ tumours to ‘hot’ ones, thereby advancing the development of anti-tumour immune drugs. Statement of significanceA biogenic MnSe (Bio-MnSe) nanocomposite was synthesized using Chlorella vulgaris as a bioreactor for enhanced immunotherapy of TNBC. Bio-MnSe demonstrated a stronger ability to activate the cGAS-STING signalling pathway and generate more ROS compared to pure Se nanoparticles and free Mn2+ ions. Apoptotic cells induced by Bio-MnSe released a significant amount of interferon, leading to the activation of T and natural killer (NK) cells, ultimately transforming immunologically ‘cold’ breast tumours to ‘hot’ tumours and enhancing the tumour's response to immune checkpoint inhibitors. The combination of Bio-MnSe with Dox or αPD-L1 further enhanced the anti-tumour immune response, fostering dendritic cell maturation, infiltration of cytotoxic T lymphocytes, and recruitment of NK cells, thereby enhancing the anti-tumour immunotherapy of TNBC.