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

Combined impact of biosynthesized selenium nanoparticles and imipenem against carbapenem-resistant Pseudomonas aeruginosa and their associated virulence factors

BACKGROUND

Carbapenem-resistant P. aeruginosa (CRPA) is a significant nosocomial pathogen characterized by extensive antibiotic resistance, representing a serious public health concern. It is regarded as a high-priority target for antibacterial research. This study aimed to isolate and identify CRPA isolates and the biosynthesis of selenium nanoparticles (Se-NPs) as a novel therapeutic approach for combating CRPA strains and their capacity to form biofilms, alone or in combination with imipenem.

METHODS

CRPA isolates were isolated from different clinical samples, identified, and subjected to antibiotic profiling using Vitek-2 method. The detection of biofilm was performed using Congo red agar (CRA), Microdilution broth assay (MBA), and qRT-PCR detection of Bap and ompA genes. Biosynthesis of Se-NPs with a cell-free filter (CFF) of Streptomyces sp. was done and characterized with various techniques, including UV-Vis, XRD, TEM, FTIR, and Zeta potential measurement. The antibacterial efficacy and minimum inhibitory concentrations (MICs) were determined using disc diffusion and microdilution techniques. The checkerboard assay was used to formulate various combinations of imipenem and Se-NPs, alongside time-kill assays to assess their antimicrobial efficacy. Furthermore, the cytotoxic effects and hemolytic activity of Se-NPs, imipenem and their combination were assessed.

RESULTS

The identification process and antibiotic susceptibility testing confirmed that the bacterial isolates were found to be CRPA. Phenotypic analysis revealed that the CRPA produced biofilm, and qRT-PCR demonstrated that all CRPA strains under study have the Bap and ompA genes. The CFF of Streptomyces sp. was able to biosynthesize Se-NPs which presented UV-Visible spectrometric profile with sharp peak at 290 nm. Se-NPs appeared to be a spherical shape, with particle sizes ranging from 20 to 100 nm under TEM and have zeta potential value of -40 mV. The MICs of Se-NPs and imipenem ranged from 6 to 14 and 12 to 14 µg/ml, respectively. The fractional inhibitory concentration index (FICI) values ranged from 0.37 to 0.50 against tested CRPA strain with a significant reduction in the concentrations of Se-NPs and imipenem. QRT-PCR showed that Se-NPs alone or combination of Se-NPs and imipenem led to a reduction of Bap and ompA gene expression compared to control (p ≤ 0.0001). The study showed a significant difference in cell viability was observed across normal or cancer cell lines at high concentrations. However, the combination of Se-NPs and imipenem demonstrated enhanced selectivity toward cancer cells, with HepG-2 cells showing significantly lower viability compared to normal HFP-4 cells across all tested concentrations. Se-NPs alone showed moderate hemolysis percentages of 1.9% at 12 h and 2.3% at 24 h while the hemolytic activity Se-NPs and imipenem combination was reduced to 1.4% and 1.7% at 12 and 24 h, representing approximately 26% and 26% reductions in haemolysis compared to Se-NPs alone at the respective time points.

CONCLUSION

This study confirms that the biosynthesized Se-NPs exhibit potent synergistic effects with imipenem against CRPA, significantly reducing biofilm formation and the expression of virulence genes Bap and ompA.

Antibacterial potential of silver-selenium nanocomposites in mitigating fire blight disease in Pyrus communis L

Pyrus communis L. is a vital fruit tree known for its nutritional and economic importance. Thus, for humans, it is an essential element for their balanced nutritional diet, as it contains the major dietary fibers, vitamins, and minerals. All of these nutritionally important aspects decrease with the impact of disease fire blight. Erwinia amylovora is a causative agent of fire blight. This infection causes a considerable loss in the production of Pyrus communis L. Annually, approximately 50% of pear fruit in Pakistan is misplaced because of these illnesses. Therefore, we propose nanotechnology remediation to treat pear plants and obtain the desired yield. In this regard, an experiment was designed to treat infected plants with different concentrations of silver-selenium nanocomposites, which was based on a literature review that indicated the antimicrobial activities of silver and selenium nanoparticles. Silver-selenium nanocomposites were prepared using a green synthesis method, and their synthesis was confirmed using characterization techniques. The experiment was performed at a farmhouse in Chakwal district, Punjab, Pakistan. The experimental results showed increased morphological, physiological, and biochemical parameters. In this regard, the best treatment remained at 50 ppm for the Ag-Se nanocomposite, which improved the plant in different aspects. At the same time, they have improved fruit metrics, such as vitamin C, pH, and juice content. Thus, these results show a possible improvement in enhancing the resistance against fire blight by using green-synthesized Ag-Se NCs. Further studies are needed to understand fully the molecular mechanisms and actions of Pyrus communis L. in treating fire blight disease and to establish the optimal treatment plan.

Nanotechnology for controlling mango malformation: a promising approach

Mango (Mangifera indica L.) is one of the most important fruit crops in the world with yields of approximately 40 million tons annually and its production continues to decrease every year as a result of the attack of certain pathogens i.e. Colletotrichum gloeosporioides, Erythricium salmonicolor, Amritodus atkinsoni, Idioscopus clypealis, Idioscopus nitidulus, Bactrocera obliqua, Bactrocera frauenfeldi, Xanthomonas campestris, and Fusarium mangiferae. So F. mangiferae is the most harmful pathogen that causes mango malformation disease in mango which decreases its 90% yield. Nanotechnology is an eco-friendly and has a promising effect over traditional methods to cure fungal diseases. Different nanoparticles possess antifungal potential in terms of controlling the fungal diseases in plants but applications of nanotechnology in plant disease managements is minimal. The main focus of this review is to highlight the previous and current strategies to control mango malformation and highlights the promising applications of nanomaterials in combating mango malformation. Hence, the present review aims to provide brief information on the disease and effective management strategies.

Preclinical Evaluation of Selene-Ethylenelacticamides in Tuberculosis: Effects Against Active, Dormant, and Resistant Mycobacterium Tuberculosis and In Vitro Toxicity Investigation

Selene-ethylenelacticamide derivatives have been suggested as promising scaffolds with leishmanicidal activity. In this work, we demonstrated, for the first time, the effectiveness of selene-ethylenelacticamide derivatives against mycobacteria. Firstly, selene-ethylenelacticamides inhibited the growth of laboratory strains of Mycobacterium tuberculosis with MIC values ranging from 10 to 20 µM. Importantly, three derivatives were active against two multi-drug-resistant clinical isolates of M. tuberculosis with MIC values similar to pan-sensitive strains. In addition, NC31 and NC34 displayed an improved activity compared to the group treated with isoniazid in the six-week nutrient-starved M. tuberculosis cultures. Moreover, in toxicity studies, NC34 did not significantly affect the viability of both Vero E6 and HepG2 cell lines. NC34 did not affect Artemia salina nauplii survival at concentrations lower than 100 µM. Importantly, NC34 displayed a synergistic effect when combined with rifampicin. Molecular docking simulations were used to evaluate Mycobacterium tuberculosis DprE1 and dihydrofolate reductase enzymes as putative targets of selene-ethylenelacticamides, mechanisms that could contribute to the antitubercular activity. Our findings reveal that NC34 may represent a hit for further drug optimization and for future preclinical development as a new anti-mycobacterial agent, especially in cases of resistant and/or dormant forms of tuberculosis.

Targeting Spore-Forming Bacteria: A Review on the Antimicrobial Potential of Selenium Nanoparticles

Spore-forming bacterial species pose a serious threat to food plants and healthcare facilities that use high-temperature processing and sterilizing techniques to sanitize medical equipment and food items. These severe processing conditions trigger sporulation, which is the process by which spore-forming bacteria, such as those of the Bacillus and Clostridium species, begin to produce spores, which are extremely resilient entities capable of withstanding adverse environmental circumstances. Additionally, these spores are resistant to a wide range of disinfectants and antibacterial therapies, such as hydrolytic enzymes, radiation, chemicals, and antibiotics. Because of their ability to combat bacteria through several biological pathways, selenium nanoparticles (SeNPs) have emerged as an effective method for either eliminating or preventing the formation of spore-forming bacteria. This review aims to investigate every potential pathway of entry and mechanism by which SeNPs impact bacterial species that produce spores. Additionally, SeNPs' antibacterial efficacy against several infections is reviewed. To precisely explain the antibacterial mechanism of SeNPs and the various factors that can affect their effectiveness, more research is necessary.

Antibacterial Capabilities of Metallic Nanoparticles and Influencing Factors

The increase of antibiotic resistance in bacteria has become a major concern for successful diagnosis and treatment of infectious diseases. Over the past few decades, significant progress has been achieved on the development of nanotechnology‐based medicines for combating multidrug resistance in microorganisms. Among these, metallic nanoparticles (MNPs) hold great promise in addressing this challenge due to their broad‐spectrum and robust antimicrobial properties. This review illustrates the antibacterial activities of MNPs and further elucidates how different factors including synthesis method, size, shape, surface charge, pH, dose, type of capping or stabilizing agents of MNPs, and Gram‐type of the bacteria, impact their antibacterial activities, which are expected to promote the future development of more potent MNP‐based antibacterial agents.

Synthesis and characterization of selenium nanoparticles stabilized with oxyethylated alkylphenol (neonol) for potential modification of fabric materials

This work demonstrates the first time synthesis of selenium nanoparticles (Se NPs) stabilized with neonol. The synthesis method was optimized using a multifactorial experiment with three input parameters. The most stable sample had a radius of 15 nm and a ζ-potential of -36.76 mV. It was found that the optimal parameters for the synthesis of Se NPs stabilized with neonol are the following concentration values: 0.12 mol/L selenic acid, 0.095 mol/L neonol and 0.95 mol/L ascorbic acid. Quantum chemical modeling of Se-neonol molecular complex formation showed that interaction of Se with neonol occurs through a hydroxyl group. Difference in the total energy of the neonol molecule and Se-neonol molecular complex is more than 2399 kcal/mol, which indicates that formation of chemical bond between Se and neonol is energetically advantageous. It was found that all samples exhibit stability over the entire pH range from 1.81 to 11.98, and the particle size is in the range of 25-30 nm. The analysis of the study of the influence of the ionic force showed that cations do not significantly affect the Se NPs radius, but anions have a significant effect, increasing the average hydrodynamic radius up to 2750 nm. For modification with Se NPs, silk, gauze, wool, cotton and cardboard samples were used. Elemental mapping of the samples showed an ambiguous distribution of Se NPs over the surface of fabric material. Assessment of potential antibacterial activity of modified fabric materials revealed inhibition zones of Micrococcus luteus growth from 12 to 16 mm for silk, gauze, wool and cotton. Notably, the most intense inhibition of Micrococcus luteus was observed in wool treated be Se NPs stabilized with neonol. Cardboard did not express Micrococcus luteus growth inhibition action because of weak interaction of cellulose filaments with Se NPs and neonol and possible microbial digestion of cellulose and xylan.

Application of nano-ZnO in the food preservation industry: antibacterial mechanisms, influencing factors, intelligent packaging, preservation film and safety

In recent years, how to improve the functional performance of food packaging materials has received increasing attention. One common inorganic material, nanometer zinc oxide (ZnO-NPs), has garnered significant attention due to its excellent antibacterial properties and sensitivity. Consequently, ZnO-NP-based functional packaging materials are rapidly developing in the food industry. However, there is currently a lack of comprehensive and systematic reviews on the use of ZnO-NPs as functional fillers in food packaging. In this review, we introduced the characteristics and antibacterial mechanism of ZnO-NPs, and paid attention to the factors affecting the antibacterial activity of ZnO-NPs. Furthermore, we systematically analyzed the application of intelligent packaging and antibacterial packaging containing ZnO-NPs in the food industry. At the same time, this paper also thoroughly investigated the impact of ZnO-NPs on various properties including thickness, moisture resistance, water vapor barrier, mechanical properties, optical properties, thermal properties and microstructure of food packaging materials. Finally, we discussed the migration and safety of ZnO-NPs in packaging materials. ZnO-NPs are safe and have negligible migration rates, simultaneously their sensitivity and antibacterial properties can be used to detect the quality changes of food during storage and extend its shelf life.

Antibiofilm and antivirulence activity of selenium nanoparticles synthesized from cell-free extract of moderately halophilic bacteria

Biofilm-forming microbes can pose a major health risk that is difficult to combat. Nanotechnology, on the other hand, represents a novel technique for combating and eliminating biofilm-forming microbes. In this study, the selenium nanoparticles (SeNPs) were biosynthesized from moderate halophilic bacteria isolated from Pichavaram mangrove sediments. The bacterial strain S8 was found to be efficient for SeNPs synthesis and hence identified by 16s r RNA sequencing as Shewanella sp. In UV- spectral analysis the SeNPs displayed a peak at 320 nm due to surface plasmon resonance (SPR). The cell-free extract of Shewanella sp. and SeNPs indicates that the various functional groups in the cell-free extract were mainly involved in the synthesis and stabilization of SeNPs. The SeNPs had a spherical form with average diameter of 49 ± 0.01 nm, according to the FESEM analysis. The EDX shows the distinctive peaks of selenium at 1.37, 11.22.12.49 Kev. In the agar well diffusion method, the SeNPs show inhibitory activity against all the test pathogens with the highest activity noted against P.aeruginosa with a zone of inhibition of 22.7 ± 0.3 mm. The minimal inhibitory concentration (MIC) value of 80 μg/ml, minimal bactericidal concentration (MBC) of 160 μg/ml, and susceptibility constant of 0.043 μg/ml show that SeNPs highly effective against P.aeruginosa. The Sub-MIC value of SeNPs of 20 μg/ml was found to inhibit P.aeruginosa biofilm by 85% as compared to the control. Further, the anti-virulence properties viz., pyocyanin, pyoverdine, hemolytic, and protease inhibition revealed the synthesized SeNPs from halophilic bacteria control the pathogenicity of P.aeruginosa.

Application of edible nanocomposites from chitosan/fenugreek seed mucilage/selenium nanoparticles for protecting lemon from green mold

Green (Penicillium digitatum) mold can severely endanger the citrus fruits production and quality. Targeting the protection of lemon fruits from green mold infestations with nanobiotechnology approach, the fenugreek seed mucilage (FM) was extracted and exploited for biosynthesis of selenium (SeNPs) nanoparticles; their nanocomposites (NCs) with chitosan (CT) was constructed and employed as antifungal materials and edible coating (ECs) to protect lemon fruits against green mold. The nanoparticles formation and conjugations were verified by infrared (FTIR) analysis and electron microscopy. The FM-synthesized SeNPs had particles average of 8.35 nm, were the NCs of them with CT had size mean of 49.33 nm and charged with +22.8 mV. The CT/FM/SeNPs composite exhibited superior antifungal actions toward P. digitatum isolates, up to 32.2 mm inhibition diameter and 12.5 mg/mL inhibitory concentration, which exceeded the actions of imazilil. The microscopic screening of exposed P. digitatum to NCs clarified their mycelial destructive action within 30 h. The coating of infected lemons with fabricated NCs led to complete elimination of green mold development after 10 days of coating, without any infestation remarks. The innovative fabrication of NCs from CT/FM/SeNPs is strongly suggested to protect citrus crops from green mold and preserve fruits quality.

Nanoselenium attenuates renal ischemia-reperfusion injury in rats

Using selenium (Se) nanoparticles has received attention in recent years because of their therapeutic benefits due to their anticancer, antioxidant, anti-inflammatory, and anti-diabetic effects. This research was conducted to evaluate the possible protective impact of nano-Se on renal unilateral ischemia/reperfusion injury (uIRI) in adult male Wistar rats. Using clamping of the left renal pedicle within 45 min uIRI was induced. The animals were randomly divided into nine groups of control, nano-Se (0.25, 0.5, and 1 mg/kg bw/day) alone, uIRI control, and uIRI rats administrated with nano-Se. At 30 days after treatment, the animals were sacrificed to be assessed biochemically and histopathologically. Nano-Se in uIRI groups have significantly decreased serum creatinine, urea levels, renal histological damage, and increased antioxidant status. Also, our findings demonstrated that the administration of nano-Se caused a significant decrease in the immunoreactivity level of the epidermal growth factor (EGF) and EGFR expression (EGF receptor) in the renal tissue of the uIRI rats. Therefore, nano-Se possesses renoprotective effects, and this effect might be attributable to its antioxidant and free radical scavenger effects. These renoprotective effects may depend on the decreased EGF immunoreactivity level and EGFR expression in the kidney tissue and improve the structure of the kidney tissue. Thus, our research provided biochemical and histological data supporting the potential clinical use of nano-Se for the treatment of certain kidney disorders.

Antimicrobial activity of probiotic bacteria-mediated cadmium oxide nanoparticles against fish pathogens

The current research was designed to investigate the antibacterial activity of probiotic bacteria mediated cadmium oxide nanoparticles (CdO NPs) on common fish pathogenic bacteria like Serratia marcescens, Aeromonas hydrophila, Vibrio harveyi, and V. parahaemolyticus. CdO NPs were synthesized using probiotic bacteria as follows: Lactobacillus species with different precursor of cadmium sulfate concentrations (5, 10, and 20 mM). The average crystalline sizes of the CdO NPs were determined based on the XRD patterns using the Debye-Scherrer equation for different precursor concentrations. Specifically, sizes of 40, 48, and 67 nm were found at concentrations of 5, 10, and 20 mM, respectively. The antibacterial efficacy of CdO NPs was estimated using a well diffusion assay, which demonstrated the best efficacy of 20 mM CdO NPs against all pathogens. AFM analysis of nanoparticle-treated and untreated biofilms was performed to further validate the antibacterial effect. Antibacterial activity of CdO nanoparticles synthesized at varying concentrations (5, 10, and 20 mM) against fish pathogens (S. marcescens, A. hydrophila, V. harveyi, and V. parahaemolyticus). The results indicated the highest inhibitory effect of 20 mM CdO NPs across all concentrations (30, 60, and 90 μg/mL), demonstrating significant inhibition against S. marcescens. These findings will contribute to the development of novel strategies for combating aquatic diseases and advancing aquaculture health management practices.

Nelumbo nucifera synthesized selenium nanoparticles modulate the immune-antioxidants, biochemical indices, and pro/anti-inflammatory cytokines pathways in Oreochromis niloticus infected with Aeromonas veronii

Bacterial infection is considered one of the major issues in fish culturing that results in economic losses. Metal nanoparticles are a cutting-edge and effective disease management and preventive strategy because of their antibacterial ability. In this investigation, the selenium nanoparticles were prepared by a biological method using Nelumbo nucifera leaves extract. The in-vitro antibacterial activity of N. nucifera synthesized selenium nanoparticles (NN-SeNPs) was tested against Aeromonas veronii. A treatment assay was conducted on 210 Oreochromis niloticus (average body weight: 27 ± 2.00 g). A preliminary approach was conducted on 90 fish for determination of the therapeutic concentration of NN-SeNPs which was found to be 4 mg/L. Fish (n = 120) were categorized into four groups for 10 days; G1 (control) and G2 (NN-SeNPs) were non-challenged and treated with 0 and 4 mg/L NN-SeNPs, respectively. While, G3 and G4 were infected with 2 × 106 CFU/mL of A. veronii and treated with 0 and 4 mg/L NN-SeNPs, respectively. NN-SeNPs exhibited an inhibition zone against A. veronii with a diameter of 16 ± 1.25 mm. The A. veronii infection increased the hepato-renal biomarkers (alanine and aspartate aminotransferases and creatinine) than the control group. An oxidative stress was the consequence of A. veronii infection (higher malondialdehyde and hydrogen peroxide levels with lower glutathione peroxidase superoxide, dismutase, and catalase activity). A. veronii infection resulted in lower immunological biomarker values (immunoglobulin M, lysozyme, and complement 3) with higher expression of the inflammatory cytokines (interleukin-1β and tumor necrosis factor-ɑ) as well as lower expression of the anti-inflammatory cytokines (interleukin-10 and transforming growth factor-β). Therapeutic application with 4 mg/L NN-SeNPs prevented the disease progression; and modulated the hepato-renal function disruptions, oxidant-immune dysfunction, as well as the pro/anti-inflammatory cytokines pathway in the A. veronii-infected fish. These findings suggest that NN-SeNPs, employed as a water therapy, can safeguard fish from the harmful effects of A. veronii and serve as a promising antibacterial agent for sustainable aquaculture.

In vitro analysis of novel trimetallic (Ag-Cu-Ni TNC) to handle benzene and benzopyrene pollutants in an aqueous environment

In this study, a trimetallic nanocomposite comprising Silver Copper-Nickel (Ag-Cu-Ni TNC) was synthesized and analysed for its efficiency in degrading benzene and benzopyrene, which has five fused benzene rings. Fabrication of trimetallic nanocomposites were characterized using UV spectroscopy, FTIR studies, SEM EDAX, and DLS results. XRD confirmed the cubic crystalline Fcc structure of Ag-Cu-Ni TNC. Photocatalytic degradation analysis revealed that Ag-Cu-Ni TNC has the efficient photocatalytic ability, and the optimum condition required for efficient degradation of benzene and benzopyrene was identified as 2 μg/mL of PAH molecule, 10 μg/mL of Ag-Cu-Ni TNC at pH 5, stirring time of 2 h placed under UV light. Based on these optimum conditions, kinetic and isotherm studies were performed, revealing that the adsorption of benzene and benzopyrene by Ag-Cu-Ni TNC fits well with the Pseudo-second order kinetic model and Freundlich isotherm model. Thus, our study's adsorption of PAH molecule from aqueous solution takes place through chemisorption and involves heterogeneous adsorption phenomena.

Nano-Selenium inhibited antibiotic resistance genes and virulence factors by suppressing bacterial selenocompound metabolism and chemotaxis pathways in animal manure

Numerous antibiotic resistance genes (ARGs) and virulence factors (VFs) found in animal manure pose significant risks to human health. However, the effects of graphene sodium selenite (GSSe), a novel chemical nano-Selenium, and biological nano-Selenium (BNSSe), a new bioaugmentation nano-Se, on bacterial Se metabolism, chemotaxis, ARGs, and VFs in animal manure remain unknown. In this study, we investigated the effects of GSSe and BNSSe on ARGs and VFs expression in broiler manure using high-throughput sequencing. Results showed that BNSSe reduced Se pressure during anaerobic fermentation by inhibiting bacterial selenocompound metabolism pathways, thereby lowering manure Selenium pollution. Additionally, the expression levels of ARGs and VFs were lower in the BNSSe group compared to the Sodium Selenite and GSSe groups, as BNSSe inhibited bacterial chemotaxis pathways. Co-occurrence network analysis identified ARGs and VFs within the following phyla Bacteroidetes (genera Butyricimonas, Odoribacter, Paraprevotella, and Rikenella), Firmicutes (genera Lactobacillus, Candidatus_Borkfalkia, Merdimonas, Oscillibacter, Intestinimonas, and Megamonas), and Proteobacteria (genera Desulfovibrio). The expression and abundance of ARGs and VFs genes were found to be associated with ARGs-VFs coexistence. Moreover, BNSSe disruption of bacterial selenocompound metabolism and chemotaxis pathways resulted in less frequent transfer of ARGs and VFs. These findings indicate that BNSSe can reduce ARGs and VFs expression in animal manure by suppressing bacterial selenocompound metabolism and chemotaxis pathways.

Oxidative stress generated due to photocatalytic activity of biosynthesized selenium nanoparticles triggers cytoplasmic leakage leading to bacterial cell death

The present work investigates the role of oxidative stress generated at biosynthesized selenium nanoparticles (SeNPs) interface in defining the antimicrobial and anti-biofilm activity. To this end, SeNPs with average size of 119 nm were synthesized rapidly during the growth of Staphylococcus aureus using the principle of green chemistry. The synthesis of SeNPs was confirmed by using different biophysical techniques like UV-vis spectroscopy, X-ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM), EDX and zeta potential analysis. The obtained data from antimicrobial study revealed strong antimicrobial activity against both Gram-positive bacteria like Bacillus subtilis (MTCC 441) and Gram-negative bacteria like Escherichia coli (MTCC 443) and anti-biofilm activity against biofilm forming bacteria. The mechanism behind antimicrobial activity of biosynthesized SeNPs was explored by evaluating the amount of reactive oxygen species (ROS) generated at SeNPs interface due to photocatalytic activity. The experimental data obtained altogether concluded that, the ROS generated at SeNPs interface put stress on bacterial cell membrane causing leakage of cytoplasmic contents, leading to bacterial cell death.

Selenium nanoparticles: Properties, preparation methods, and therapeutic applications

Selenium nanoparticles (SeNPs) are a unique type of nano-sized elemental selenium that have recently found wide application in biomedicine. It has been shown that the properties of SeNPs can be varied by different fabrication methods. Moreover, SeNPs have various therapeutic effects in medical applications due to their excellent biological and adaptable physical properties. At the same time, SeNPs can be used as a carrier medium for various therapeutic substances, which can bring out the full curative effects of the drugs. In this review, the differences in bioactivity properties of SeNPs prepared from different substances were reviewed; the therapeutic effects and mechanisms of SeNPs in cancer, inflammation, neurodegenerative diseases, diabetes, reproductive diseases, cardiovascular diseases, and other diseases were discussed; and the importance of the development of SeNPs was further emphasized.

Evaluation of Selenium Nanoparticles in Inducing Disease Resistance against Spot Blotch Disease and Promoting Growth in Wheat under Biotic Stress

In the present study, SeNPs were synthesized using Melia azedarach leaf extracts and investigated for growth promotion in wheat under the biotic stress of spot blotch disease. The phytosynthesized SeNPs were characterized using UV-visible spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and Fourier-transformed infrared spectroscopy (FTIR). The in vitro efficacy of different concentrations of phytosynthesized SeNPs (i.e., 100 μg/mL, 150 μg/mL, 200 μg/mL, 250 μg/mL, and 300 μg/mL) was evaluated using the well diffusion method, which reported that 300 μg/mL showed maximum fungus growth inhibition. For in vivo study, different concentrations (10, 20, 30, and 40 mg/L) of SeNPs were applied exogenously to evaluate the morphological, physiological, and biochemical parameters under control conditions and determine when infection was induced. Among all treatments, 30 mg/L of SeNPs performed well and increased the plant height by 2.34% compared to the control and 30.7% more than fungus-inoculated wheat. Similarly, fresh plant weight and dry weight increased by 17.35% and 13.43% over the control and 20.34% and 52.48% over the fungus-treated wheat, respectively. In leaf surface area and root length, our findings were 50.11% and 10.37% higher than the control and 40% and 71% higher than diseased wheat, respectively. Plant physiological parameters i.e., chlorophyll a, chlorophyll b, and total chlorophyll content, were increased 14, 133, and 16.1 times over the control and 157, 253, and 42 times over the pathogen-inoculated wheat, respectively. Our findings regarding carotenoid content, relative water content, and the membrane stability index were 29-, 49-, and 81-fold higher than the control and 187-, 63-, and 48-fold higher than the negative control, respectively. In the case of plant biochemical parameters, proline, sugar, flavonoids, and phenolic contents were recorded at 6, 287, 11, and 34 times higher than the control and 32, 107, 33, and 4 times more than fungus-inoculated wheat, respectively. This study is considered the first biocompatible approach to evaluate the potential of green-synthesized SeNPs as growth-promoting substances in wheat under the spot blotch stress and effective management strategy to inhibit fungal growth.

Antifungal activity of green synthesized selenium nanoparticles and their effect on physiological, biochemical, and antioxidant defense system of mango under mango malformation disease

Plant extract-based green synthesis of nanoparticles is an emerging class of nanotechnology that has revolutionized the entire field of biological sciences. Green synthesized nanoparticles are used as super-growth promoters and antifungal agents. In this study, selenium nanoparticles (SeNPs) were synthesized using Melia azedarach leaves extract as the main reducing and stabilizing agent and characterized by UV-visible spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray (EDX), and fourier transform infrared spectrometer (FTIR). The green synthesized SeNPs were exogenously applied on Mangifera indica infected with mango malformation disease. The SeNPs at a concentration of 30 μg/mL were found to be the best concentration which enhanced the physiological (chlorophyll and membrane stability index), and biochemical (proline and soluble sugar) parameters. The antioxidant defense system was also explored, and it was reported that green synthesized SeNPs significantly reduced the biotic stress by enhancing enzymatic and non-enzymatic activities. In vitro antifungal activity of SeNPs reported that 300 μg/mL concentration inhibited the Fusarium mangiferae the most. This study is considered the first biocompatible approach to evaluate the potential of green synthesized SeNPs to improve the health of mango malformation-infected plants and effective management strategy to inhibit the growth of F. mangifera.

Amelioration Strategies for Silver Diamine Fluoride: Moving from Black to White

Topical cariostatic agents have become a reasonable alternative for managing dental caries in young children. Silver diamine fluoride (SDF) is a practical topical approach to arrest caries and avoid extensive and risky dental treatment. However, the literature demonstrates a parental hesitation towards accepting SDF because of black unaesthetic tooth discolouration following application. The rapid oxidation of ionic silver darkens demineralised tooth structure permanently. In this regard, nano-metallic antimicrobials could augment or substitute for silver, and thereby enhance SDF aesthetic performance. Recently, biomedical research has drawn attention to selenium nanoparticles (SeNPs) due to their antimicrobial, antioxidant, and antiviral potencies. Various in vitro studies have examined the effect of SeNPs on the virulence of bacteria. This narrative review explores practical issues when using SDF and suggests future directions to develop it, focusing on antimicrobial metals. Several methods are described that could be followed to reduce the discolouration concern, including the use of nanoparticles of silver, of silver fluoride, or of selenium or other metals with antimicrobial actions. There could also be value in using remineralising agents other than fluoride, such as NPs of hydroxyapatite. There could be variations made to formulations in order to lower the levels of silver and fluoride in the SDF or even to replace one or both of the silver and fluoride components completely. Moreover, since oxidation processes appear central to the chemistry of the staining, adding SeNPs which have antioxidant actions could have an anti-staining benefit; SeNPs could be used for their antimicrobial actions as well. Future research should address the topic of selenium chemistry to optimise how SeNPs would be used with or in place of ionic silver. Incorporating other antimicrobial metals as nanoparticles should also be explored, taking into account the optimal physicochemical parameters for each of these.

Metallic Nanosystems in the Development of Antimicrobial Strategies with High Antimicrobial Activity and High Biocompatibility

Antimicrobial resistance is a major and growing global problem and new approaches to combat infections caused by antibiotic resistant bacterial strains are needed. In recent years, increasing attention has been paid to nanomedicine, which has great potential in the development of controlled systems for delivering drugs to specific sites and targeting specific cells, such as pathogenic microbes. There is continued interest in metallic nanoparticles and nanosystems based on metallic nanoparticles containing antimicrobial agents attached to their surface (core shell nanosystems), which offer unique properties, such as the ability to overcome microbial resistance, enhancing antimicrobial activity against both planktonic and biofilm embedded microorganisms, reducing cell toxicity and the possibility of reducing the dosage of antimicrobials. The current review presents the synergistic interactions within metallic nanoparticles by functionalizing their surface with appropriate agents, defining the core structure of metallic nanoparticles and their use in combination therapy to fight infections. Various approaches to modulate the biocompatibility of metallic nanoparticles to control their toxicity in future medical applications are also discussed, as well as their ability to induce resistance and their effects on the host microbiome.

Biogenic Selenium Nanoparticles in Biomedical Sciences: Properties, Current Trends, Novel Opportunities and Emerging Challenges in Theranostic Nanomedicine

Selenium is an important dietary supplement and an essential trace element incorporated into selenoproteins with growth-modulating properties and cytotoxic mechanisms of action. However, different compounds of selenium usually possess a narrow nutritional or therapeutic window with a low degree of absorption and delicate safety margins, depending on the dose and the chemical form in which they are provided to the organism. Hence, selenium nanoparticles (SeNPs) are emerging as a novel therapeutic and diagnostic platform with decreased toxicity and the capacity to enhance the biological properties of Se-based compounds. Consistent with the exciting possibilities offered by nanotechnology in the diagnosis, treatment, and prevention of diseases, SeNPs are useful tools in current biomedical research with exceptional benefits as potential therapeutics, with enhanced bioavailability, improved targeting, and effectiveness against oxidative stress and inflammation-mediated disorders. In view of the need for developing eco-friendly, inexpensive, simple, and high-throughput biomedical agents that can also ally with theranostic purposes and exhibit negligible side effects, biogenic SeNPs are receiving special attention. The present manuscript aims to be a reference in its kind by providing the readership with a thorough and comprehensive review that emphasizes the current, yet expanding, possibilities offered by biogenic SeNPs in the biomedical field and the promise they hold among selenium-derived products to, eventually, elicit future developments. First, the present review recalls the physiological importance of selenium as an oligo-element and introduces the unique biological, physicochemical, optoelectronic, and catalytic properties of Se nanomaterials. Then, it addresses the significance of nanosizing on pharmacological activity (pharmacokinetics and pharmacodynamics) and cellular interactions of SeNPs. Importantly, it discusses in detail the role of biosynthesized SeNPs as innovative theranostic agents for personalized nanomedicine-based therapies. Finally, this review explores the role of biogenic SeNPs in the ongoing context of the SARS-CoV-2 pandemic and presents key prospects in translational nanomedicine.

Embryonic exposure to selenium nanoparticles delays growth and hatching in the freshwater snail Lymnaea stagnalis

Selenium nanoparticles (SeNPs) have been applied in the biomedical and biocidal domain which may have potential environmental risks for aquatic systems. However, the knowledge of its toxicity and the role of functionalization on aquatic invertebrates are scarce. Thus, the present study aimed to analyze the embryotoxicity of two types of SeNPs coated with Sodium carboxymethyl cellulose (CMC-SeNPs) and Chitosan (CS-SeNPs) to the freshwater snail Lymnaea stagnalis in lake water, focusing on embryonic development. The influence of surface coatings and ions release, on the embryonic development of SeNPs to freshwater snail L. stagnalis was investigated. For this end, the snails were exposed to different concentrations of SeNPs and Se ions (0.05-1 mg L^-1) during 7 days and multiple endpoints were analyzed, including developmental stage frequency, morphological alterations, embryos mortality and hatching success. The results showed that both Se forms promoted the developmental delay, mortality, morphological changes, and hatching inhibition in snail embryos in a concentration-dependent manner. CMC-SeNPs are 2.6 times more embryotoxic compared to CS-SeNPs indicating the importance of surface coating on the embryotoxicity. Moreover, the results revealed that although both forms of Se inhibited the embryo development and reduced the hatching of L. stagnalis, the mode of action on the embryogenesis was different. SeNPs had a higher toxicity to snails' embryos compared to their dissolved counterparts. Despite significant dissolution, by comparing the SeNPs with their dissolved fraction, the results suggest SeNPs inhibition effect on the snail development could be caused by both SeNPs and Se⁴⁺, and SeNPs might be the major development retardation driver rather than Se ions. The present study evidenced by the first time the toxicity effects of SeNPs on the snail embryogenesis, and highlighted how SeNPs intrinsic properties influence their transformation and toxicity in environmental relevant scenarios.

Therapeutic potential of selenium nanoparticles

Diseases have always been a disconcerting issue and have changed into being an inevitable member of the world’s population. Medical advancements have brought in improved treatments for particular ailments, but unfortunately those betterments have resulted in either side effects or turned out futile to a certain extent. The emergence of nanotechnology has considerably benefitted medical experts in disease diagnosis and therapeutics. Currently, an expansive range of nanoparticles is being explored for their effectiveness in therapies, and one among them is selenium nanoparticles (SeNPs). Nano-selenium exhibits significant properties which make it best suited for this purpose. The article highlights the key role of SeNPs in treating major diseases like cancer, diabetes, and microbial infections.

Designated functional microcapsules loaded with green synthesis selenium nanorods and probiotics for enhancing stirred yogurt

Green synthesis selenium nanorods (Se-NRs) were produced based on Aloe vera leaf extract. The size, morphology, antimicrobial, and activation of Se-NRs for probiotics were analyzed. The Se-NRS was stable with a diameter of 12 and 40 nm, had an antimicrobial effect, and improved probiotics counts. The microcapsules loaded with Green Se-NRS (0, 0.05 or 0.1 mg/100 ml) and probiotics (Bifidobacterium lactis and Lactobacillus rhamnosus) were designated with efficiency between 95.25 and 97.27% and irregular shapes. Microcapsules were saved probiotics against gastrointestinal juices. The microcapsules were showed a minor inhibition effect against the cell line. Also, microcapsules integrated into stirred yogurt and exanimated for microbiology, chemically, and sensory for 30 days. The probiotics counts, acidity, total solids, and ash values of samples were increased during storage periods without affecting fat and protein contents. The overall acceptability of yogurt with microcapsules containing probiotics and Se-NRs was high without change in body, odor, color, and appearance.

Construction of inulin-based selenium nanoparticles to improve the antitumor activity of an inulin-type fructan from chicory

Cancer has become one of the leading causes of death worldwide. It is urgent to develop new antitumor drugs with high efficiency and low toxicity. In this study, an inulin-type fructan CIP70-1 was purified and characterized from chicory and showed weak antitumor activity. To improve its antitumor effects, inulin-based selenium nanoparticles (CIP-SeNPs) were constructed and characterized. CIP-SeNPs were spherical nanoparticles (60 nm), which remained stable in water for more than 3 months. A cellular antitumor assay revealed that CIP-SeNPs had stronger inhibitory effects on cancer cells (MCF-7, A549, and HepG2) than CIP70-1 alone. Furthermore, the in vivo antitumor effects of CIP-SeNPs were confirmed using zebrafish models. The results showed that CIP-SeNPs significantly inhibited the proliferation and migration of tumors as well as the angiogenesis of transgenic zebrafish in the concentration range of 1-4 μg/mL.

Application of Nanocomposites from Bees Products and Nano-Selenium in Edible Coating for Catfish Fillets Biopreservation

Bee products, e.g., chitosan and propolis (Pro), have extraordinary importance in many disciplines including food biopreservation. Fish meat is highly susceptible to vast spoilage, especially catfish (Clarias gariepinus) products. The current work involved the extraction of bees’ chitosan nanoparticles (BCht), Pro, Pro-mediated SeNPs and their composites, to evaluate them as potential antimicrobial and preservative nano-compounds, for the preservation of catfish fillets and augment their quality. BCht was extracted from bees (Apis mellifera) corpses and had a 151.9 nm mean particle diameter. The Pro was used for biosynthesis of SeNPs, which had 11.2 nm mean diameters. The entire compounds/composites exhibited powerful antibacterial acts against Escherichia coli, Staphylococcus aureus and Salmonella typhimurium, where S aureus had the uppermost resistance. BCht/Pro/SeNPs were the most forceful toward all bacterial strains. The constructed edible coatings (ECs) from produced compounds/composites (BCht, Pro, Pro/SeNPs, Pro/BCht and BCht/Pro/SeNPs) had elevated efficiency for preserving catfish fillets during cold storages for 7 days. The microbiological (total counts, psychrophilic bacteria, yeast and molds), spoilage chemical parameters (TVB-N, TBARS) and sensorial attributes (appearance, odor, color, overall quality) of ECs-treated fillets indicated the nanocomposite’s efficiency for protecting the fish from microbial growth, the progress of chemical spoilage indicators and maintaining the sensorial quality of treated stored fillets. The most effective nanocomposite for maintaining the entire fillet’s quality was the BCht/Pro/SeNP. The based ECs on BNCt, Pro/SeNPs and their nanocomposites could be endorsed for prospective employment in the biopreservation of various seafoods.

Evaluation of collision/reaction gases in single-particle ICP-MS for sizing selenium nanoparticles and assessment of their antibacterial activity

Selenium nanoparticles (SeNPs) have recently attracted attention because they combine the benefits of Se and lower toxicity compared to other chemical forms of this element. In this study, SeNPs were synthesized by a green method using ascorbic acid as the reducing agent and polyvinyl alcohol as stabilizer. The nanoparticles were widely characterized. To determine the total concentration of Se by ICP-MS, several isotopes and the use of He as collision gas were evaluated, which was effective in minimizing interferences. A method for sizing SeNPs by single particle ICP-MS (SP-ICP-MS) was developed. For this purpose, He and H₂were evaluated as collision/reaction gases, and the second one showed promising results, providing an average diameter of 48 nm for the SeNPs. These results agree with those obtained by TEM (50.1 nm). Therefore, the SP-ICP-MS can be implemented for characterizing SeNPs in terms of size and size distribution, being an important analytical tool for Se and other widely studied nanoparticles (e.g. Ag, Au, Ce, Cu, Fe, Zn). Finally, the antibacterial activity of SeNPs was assessed. The SeNPs showed bacteriostatic activity against three strains of Gram-positive bacteria and were particularly efficient in inhibiting the growthE. faecaliseven at very low concentrations (MIC < 1.4 mg l^-1). In addition, a bactericidal activity of SeNPs againstS. aureuswas observed. These nanoparticles may have potential application in pharmaceutical industry, biomedicine and agriculture.

Selenium nanoparticles stimulate osteoblast differentiation via BMP-2/MAPKs/β-catenin pathway in diabetic osteoporosis

Aim: To evaluate whether selenium nanoparticles (SeNPs) can stimulate bone formation and inhibit the bone loss involved in hyperglycemia-induced osteoporosis. Methods: Rat osteoblastic UMR-106 cells were used for in vitro studies and female Sprague–Dawley rats were used for type 2 diabetes-associated osteoporosis in vivo study. Results: In vitro studies show that SeNPs promote osteoblast differentiation via modulating alkaline phosphatase (ALP) activity, and promoting calcium nodule formation and collagen content. The authors also provide evidence regarding the involvement of the BMP-2/MAPKs/β-catenin pathway in preventing diabetic osteoporosis. Further, in vivo and ex vivo studies suggested that SeNPs can preserve mechanical and microstructural properties of bone. Conclusion: To the best of our knowledge, this study provides the first evidence regarding the therapeutic benefits of SeNPs in preventing diabetes-associated bone fragility.

Antifungal application of biosynthesized selenium nanoparticles with pomegranate peels and nanochitosan as edible coatings for citrus green mold protection

Background

Citrus production and trading are seriously affected by fungal decays worldwide; the green mold infection by Penicillium digitatum could be the most disastrous. The substitutions of chemical and synthetic fungicides with effectual natural alternatives are global demands; plant extract from pomegranates peels (PPE), biosynthesized selenium nanoparticles with PPE (PPE/SeNPs) and chitosan nanoparticles (NCT) were suggested as efficacious fungicidal agents/nanocomposites to control P. digitatum strains.

Method

PPE from Punica granatum was extracted and employed directly for synthesizing SeNPs, whereas NCT was produced using ionic gelation method of chitosan extracted from white prawn (Fenneropenaeus indicus) shells. The physiochemical, biochemical and structural characterization of generated molecules were conducted using infra-red spectroscopy, particles’ size (Ps) and charge assessment and electron microscopes imaging. Antifungal potentialities were investigated in vitro and in infected fruits with P. digitatum by applying NCT nanocomposites-based edible coating.

Results

The synthesis of PPE-synthesized SeNPs and NCT was successfully achieved, the molecular bonding in synthesized agents/composites were proved with infrared spectroscopy to have both biochemical and physical interactions. The nanoparticles had 82.72, 9.41 and 85.17 nm mean diameters for NCT, PPE/SeNPs and NCT/PPE/SeNPs nanocomposites, respectively. The nanoparticles had homogenous spherical shapes and good distribution attributes. The entire agents/nanocomposites exhibited potent fungicidal potentialities toward P. digitatum isolates; NCT/PPE/SeNPs nanocomposite was the most forceful and significantly exceeded the fungicidal action of standard fungicide. The direct treatment of fungal mycelia with NCT/PPE/SeNPs nanocomposite led to remarkable lysis and deformations of P. digitatum hyphae within 12 h of treatment. The coating of infected orange with NCT-based edible coatings reduced the green mold infection signs by 91.7, 95.4 and 100%, for NCT, NCT/PPE and NCT/PPE/SeNPs based coating solutions, respectively.

Conclusions

NCT, PPE-synthesized SeNPs, and their innovative nanocomposites NCT/PPE/SeNPs are convincingly recommended for formulating effectual antifungal and edible coatings to eliminate postharvest fungal pathogen, both with protection from their invasion or with destructing their existing infections.

Graphical Abstract

Modifications of Parylene by Microstructures and Selenium Nanoparticles: Evaluation of Bacterial and Mesenchymal Stem Cell Viability

Parylene-based implants or coatings introduce surfaces suffering from bacteria colonization. Here, we synthesized polyvinylpyrrolidone-stabilized selenium nanoparticles (SeNPs) as the antibacterial agent, and various approaches are studied for their reproducible adsorption, and thus the modification of parylene-C-coated glass substrate. The nanoparticle deposition process is optimized in the nanoparticle concentration to obtain evenly distributed NPs on the flat parylene-C surface. Moreover, the array of parylene-C micropillars is fabricated by the plasma etching of parylene-C on a silicon wafer, and the surface is modified with SeNPs. All designed surfaces are tested against two bacterial pathogens, Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive). The results show no antibacterial effect toward S. aureus, while some bacteriostatic effect is observed for E. coli on the flat and microstructured parylene. However, SeNPs did not enhance the antibacterial effect against both bacteria. Additionally, all designed surfaces show cytotoxic effects toward mesenchymal stem cells at high SeNP deposition. These results provide valuable information about the potential antibacterial treatment of widely used parylene-C in biomedicine.

Synthesis of Nanocomposites of V₂O5©Selenium Nanoparticles and Multiwalled Carbon Nanotubes for Antimicrobial Activity

The authors report the preparation of the nanocomposite comprising of vanadium pentoxide (V₂O₅) and selenium (Se) nanoparticles and functionalized multiwalled carbon nanotubes (MWCNTs) (V₂O₅@Se NPs/MWCNTs). Since Se NPs possesses extraordinary physicochemical properties including larger surface area with higher adsorption capacity, V₂O₅ NPs were adsorbed onto Se NPs surface through physisorption process (designated as V₂O₅@Se NPs). The nanocomposite synthesized hydrothermally was evaluated for its antimicrobial activity. The morphology and microstructure of the nanocomposite were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis, respectively. Fourier transform infrared spectroscopy (FTIR) and UV-Visible spectroscopy (UV-Vis) were employed to analyze the spectral properties of nanocomposite. The microbicidal efficacy of nanocomposite was tested against Gram-negative (G-)ZGram-positive (G+) bacteria and fungus. This is the first report on the synthesis of V₂O₅@Se NPs/MWCNTs nanocomposites by chemical method that showed microbicidal effect on micro-organisms. The thiol (-SH) units facilitates the enrichment of V₂O₅@Se NPs onto MWCNTs surface. Ultimately, it reflects on the significant antimicrobial activity of V₂O₅@Se NPs/MWCNTs.

Elemental Selenium Enriched Nanofiber Production

This study aimed to produce electrospun nanofibers from a polyvinyl butyral polymer (PVB) solution enriched with red and grey selenium nanoparticles. Scanning electron microscopic analysis was used to observe the samples, evaluate the fiber diameters, and reveal eventual artifacts in the nanofibrous structure. Average fiber diameter is determined by manually measuring the diameters of randomly selected fibers on scanning electron microscopic (SEM) images. The obtained nanofibers are amorphous with a diameter of approximately 500 nm, a specific surface area of approx. 8 m² g⁻¹, and 5093 km cm⁻³ length. If the red and grey selenium nanoparticles were produced in powder form and suspended to the ethanolic solution of PVB then they were located inside and outside the fiber. When selenium nanoparticles were synthesized in the PVB solution, then they were located only inside the fiber. These nanofiber sheets enriched with selenium nanoparticles could be a good candidate for high-efficiency filter materials and medical applications.

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

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

Multimetallic Nanoparticles as Alternative Antimicrobial Agents: Challenges and Perspectives

Recently, infectious diseases caused by bacterial pathogens have become a major cause of morbidity and mortality globally due to their resistance to multiple antibiotics. This has triggered initiatives to develop novel, alternative antimicrobial materials, which solve the issue of infection with multidrug-resistant bacteria. Nanotechnology using nanoscale materials, especially multimetallic nanoparticles (NPs), has attracted interest because of the favorable physicochemical properties of these materials, including antibacterial properties and excellent biocompatibility. Multimetallic NPs, particularly those formed by more than two metals, exhibit rich electronic, optical, and magnetic properties. Multimetallic NP properties, including size and shape, zeta potential, and large surface area, facilitate their efficient interaction with bacterial cell membranes, thereby inducing disruption, reactive oxygen species production, protein dysfunction, DNA damage, and killing potentiated by the host's immune system. In this review, we summarize research progress on the synergistic effect of multimetallic NPs as alternative antimicrobial agents for treating severe bacterial infections. We highlight recent promising innovations of multimetallic NPs that help overcome antimicrobial resistance. These include insights into their properties, mode of action, the development of synthetic methods, and combinatorial therapies using bi- and trimetallic NPs with other existing antimicrobial agents.

Role of nano-selenium in health and environment

In recent years, researches on selenium nanoparticle have gained more attention due to its important role in many physiological processes. Generally, selenium nanoparticle has a high level of absorption in regular supplementation comparative to selenium. Therefore it is all-important to develop new techniques to elevate the transportation of selenium compounds (selenoproteins, selenoenzymes, etc.) by increasing their bioavailability, bioactivity, and controlled release. SeNPs have special attention regarding their application as food additives and therapeutic agents. Selenium nanoparticle has biomedical and pharmaceutical uses due to its antioxidant, antimicrobial, antidiabetic, and anticancer effects. Selenium nanoparticle is also used to antagonize the toxic effect of chemical and heavy metals. SeNPs are beneficial for the treatment of water and soil contaminated with metals and heavy metals as it has adsorption capability. Selenium nanoparticle is synthesized by the bioreduction of selenium species (sodium selenate, sodium selenite, selenium dioxide, and selenium tetrachloride, etc.) by using bacteria, fungi, plant, and plant extracts, which have given hope for the bioremediation of selenium contaminated water and soils. This article reviews the procedure of selenium nanoparticle synthesis (physical, chemical and biological methods), characterization (UV-vis spectroscopy, transmission electron microscopy, Scanning electron microscopy, electron dispersive X-ray spectroscopy, X-ray diffraction, Fourier transform-infrared spectroscopy, etc.), with the emphasis on its role and application in health and environment.