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

Selenium Species in Diabetes Mellitus Type 2

Selenium is an important trace element for humans and animals as it plays a key role in several major metabolic pathways. Several studies were conducted to better understand the role of selenium against diabetes mellitus (DM), particularly type 2 (T2DM), but the obtained conclusions are contradictory. A simple linear relationship does not exist between the risk of T2DM and selenium levels but is best represented in a dose-dependent manner, getting often the U-graph. This relation also depends on selenium chemical forms that are present in a diet or supplements. Both too low and too high selenium intakes could increase the risk of diabetes. Moreover, the baseline status of Se should be taken into consideration to avoid over-supplementation. The focus of this brief overview is to report the recent updates concerning selenium participation in diabetes mellitus.

Characterizations of biogenic selenium nanoparticles and their anti-biofilm potential against Streptococcus mutans ATCC 25175

INTRODUCTION

S. mutans has been identified as the primary pathogenic bacterium in biofilm-mediated dental caries. The biogenic selenium nanoparticles (SeNPs) produced by L. plantarum KNF-5 were used in this study against S. mutans ATCC 25175.

OBJECTIVES

The aims of this study were: (1) the biosynthesis of SeNPs by L. plantarum KNF-5, (2) the characterization of SeNPs, (3) the investigation of the inhibitory effect of biogenic SeNPs against S. mutans ATCC 25175, and (4) the determination of the anti-biofilm potential of SeNPS against S. mutans ATCC 25175.

METHODOLOGY

3 mL of the culture was added to 100 mL of MRS medium and incubated. After 4 h, Na2SeO3 solution (concentration 100 μg/mL) was added and incubated at 37 °C for 36 h. The color of the culture solution changed from brownish-yellow to reddish, indicating the formation of SeNPs. The characterization of SeNPs was confirmed by UV-Vis spectrophotometry, FTIR, SEM-EDS and a particle size analyzer. The antibacterial activity was determined by the disk diffusion method, the MIC by the micro-double dilution method, and the biofilm inhibitory potential by the crystal violet method and the MTT assay. The effect of SeNPs on S. mutans ATCC 25175 was determined using SEM and CLSM spectrometry techniques. The sulfate-anthrone method was used to analyze the effect of SeNPs on insoluble extracellular polysaccharides. The expression of genes in S. mutans ATCC 25175 was analyzed by real-time quantitative polymerase chain reaction (RT-qPCR).

PREPARATION OF NANOPARTICLES

SeNPs produced by probiotic bacteria are considered a safe method. In this study, L. plantarum KNF-5 (probiotic strain) was used for the production of SeNPs.

RESULTS

The biogenic SeNPs were spherical and coated with proteins and polysaccharides and had a diameter of about 270 nm. The MIC of the SeNPs against S. mutans ATCC 25175 was 3.125 mg/mL. Biofilm growth was also significantly suppressed at this concentration. The expression of genes responsible for biofilm formation (GtfB, GtfC, BrpA and GbpB,) was reduced when S. mutans ATCC 25175 was treated with SeNPs.

CONCLUSION

It was concluded that the biogenic SeNPs produced by L. plantarum KNF-5 was highly effective to inhibit the growth of S. mutans ATCC 25175.

NOVELTY STATEMENT

The application of biogenic SeNPs, a natural anti-biofilm agent against S. mutans ATCC 25175. In the future, this study will provide a new option for the prevention and treatment of dental caries.

Recent advances in the therapeutic applications of selenium nanoparticles

Selenium nanoparticles (SeNPs) are an appealing carrier for the targeted delivery. The selenium nanoparticles are gaining global attention because of the potential therapeutic applications in several diseases e.g., rheumatoid arthritis (RA), inflammatory bowel disease (IBD), asthma, liver, and various autoimmune disorders like psoriasis, cancer, diabetes, and a variety of infectious diseases. Despite the fact still there is no recent literature that summarises the therapeutic applications of SeNPs. There are some challenges that need to be addressed like finding targets for SeNPs in various diseases, and the various functionalization techniques utilized to increase SeNP's stability while facilitating wide drug-loaded SeNP distribution to tumor areas and preventing off-target impacts need to focus on understanding more about the therapeutic aspects for better understanding the science behind it. Keeping that in mind we have focused on this gap and try to summarize all recent key targeted therapies for SeNPs in cancer treatment and the numerous functionalization strategies. We have also focused on recent advancements in SeNP functionalization methodologies and mechanisms for biomedical applications, particularly in anticancer, anti-inflammatory, and anti-infection therapeutics. Based on our observation we found that SeNPs could potentially be useful in suppressing viral epidemics, like the ongoing COVID-19 pandemic, in complement to their antibacterial and antiparasitic uses. SeNPs are significant nanoplatforms with numerous desirable properties for clinical translation.

Determination of selenium-containing species, including nanoparticles, in selenium-enriched Lingzhi mushrooms

Mushrooms are considered a valuable food source due to their high protein and fibre and low fat content, among the other health benefits of their consumption. Selenium is an essential nutrient and is renowned for its chemo-preventative properties. In this study, batches of selenium-enriched Lingzhi mushrooms were prepared by growing mycelium and fruit in substrates containing various concentrations of sodium selenite. The mushroom fruit accumulated low levels of selenium with selenomethionine being the most abundant form in all enriched samples. Conversely, the mycelium showed significant selenium accumulation but relatively low proportions of selenomethionine. The red colour of the selenium-enriched mycelia indicated the probable presence of selenium nanoparticles, which was confirmed by single-particle inductively coupled plasma-mass spectrometry. Mean particle diameters of 90-120 nm were observed, with size distributions of 60-250 nm. Additional analysis with transmission electron microscopy confirmed this size distribution and showed that the biogenic selenium nanoparticles were roughly spherical in shape and contained elemental selenium.

Reduction of selenite to selenium nanoparticles by highly selenite-tolerant bacteria isolated from seleniferous soil

The microbial reduction of selenite to elemental selenium nanoparticles (SeNPs) is thought to be an effective detoxification process of selenite for many bacteria. In this study, Metasolibacillus sp. ES129 and Oceanobacillus sp. ES111 with high selenite reduction efficiency or tolerance were selected for systematic and comparative studies on their performance in selenite removal and valuable SeNPs recovery. The kinetic monitoring of selenite reduction showed that the highest transformation efficiency of selenite to SeNPs was achieved at a concentration of 4.24 mM for ES129 and 4.88 mM for ES111. Ultramicroscopic analysis suggested that the SeNPs produced by ES111 and ES129 had been formed in cytoplasm and subsequently released to extracellular space through cell lysis process. Furthermore, the transcriptome analysis indicated that the expression of genes involved in bacillithiol biosynthesis, selenocompound metabolism and proline metabolism were significantly up-regulated during selenite reduction, suggesting that the transformation of selenite to Se0 may involve multiple pathways. Besides, the up-regulation of genes associated with nucleotide excision repair and antioxidation-related enzymes may enhance the tolerance of bacteria to selenite. Generally, the exploration of selenite reduction and tolerance mechanisms of the highly selenite-tolerant bacteria is of great significance for the effective utilization of microorganisms for environmental remediation.

Molecular mechanisms of selenite reduction by Lactiplantibacillus plantarum BSe: An integrated genomic and transcriptomic analysis

The reduction of selenite [Se(Ⅳ)] by microorganisms is a green and efficient detoxification strategy. We found that Se(Ⅳ) inhibited exopolysaccharide and protein secretion by Lactiplantibacillus plantarum BSe and compromised cell integrity. In this study, L. plantarum BSe reduced Se(Ⅳ) by increasing related enzyme activity and electron transfer. Genomic analysis demonstrated that L. plantarum BSe should be able to reduce Se(Ⅳ). Further transcriptome analysis showed that L. plantarum BSe enhanced its tolerance to Se(Ⅳ) by upregulating the expression of surface proteins and transporters, thus reducing the extracellular Se(Ⅳ) concentration through related enzymatic reactions and siderophore-mediated pathways. Lactiplantibacillus plantarum BSe was able to regulate the expression of related genes involved in quorum sensing and a two-component system and then select appropriate strategies for Se(Ⅳ) transformation in response to varying environmental Se(Ⅳ) concentrations. In addition, azo reductase was linked to the reduction of Se(Ⅳ) for the first time. The present study established a multipath model for the reduction of Se(Ⅳ) by L. plantarum, providing new insights into the biological reduction of Se(Ⅳ) and the biogeochemical cycle of selenium.

Comprehensive review on recent trends and perspectives of natural exo-polysaccharides: Pioneering nano-biotechnological tools

Exopolysaccharides (EPSs), originating from various microbes, and mushrooms, excel in their conventional role in bioremediation to showcase diverse applications emphasizing nanobiotechnology including nano-drug carriers, nano-excipients, medication and/or cell encapsulation, gene delivery, tissue engineering, diagnostics, and associated treatments. Acknowledged for contributions to adsorption, nutrition, and biomedicine, EPSs are emerging as appealing alternatives to traditional polymers, for biodegradability and biocompatibility. This article shifts away from the conventional utility to delve deeply into the expansive landscape of EPS applications, particularly highlighting their integration into cutting-edge nanobiotechnological methods. Exploring EPS synthesis, extraction, composition, and properties, the discussion emphasizes their structural diversity with molecular weight and heteropolymer compositions. Their role as raw materials for value-added products takes center stage, with critical insights into recent applications in nanobiotechnology. The multifaceted potential, biological relevance, and commercial applicability of EPSs in contemporary research and industry align with the nanotechnological advancements coupled with biotechnological nano-cleansing agents are highlighted. EPS-based nanostructures for biological applications have a bright future ahead of them. Providing crucial information for present and future practices, this review sheds light on how eco-friendly EPSs derived from microbial biomass of terrestrial and aquatic environments can be used to better understand contemporary nanobiotechnology for the benefit of society.

Stabilization by Chaperone GroEL in Biogenic Selenium Nanoparticles Produced from Bifidobacterium animalis H15 for the Treatment of DSS-Induced Colitis

Inflammatory bowel diseases have a high rate of mortality and pose a serious threat to global public health. Selenium is an essential trace element, which has been shown to play important roles in redox control and antioxidant defense. Microorganisms play important roles in the reduction of toxic inorganic selenium (selenite and selenate) to less-toxic biogenic selenium nanoparticles (Bio-SeNPs), which have higher biocompatibility. In the present study, novel Bio-SeNPs with high stability were synthesized using probiotic Bifidobacterium animalis subsp. lactis H15, which was isolated from breastfed infant feces. The Bio-SeNPs with a size of 122 nm showed stability at various ionic strengths, temperatures, and in simulated gastrointestinal fluid, while chemosynthetic SeNPs underwent aggregation. The main surface protein in the Bio-SeNPs was identified as chaperone GroEL by liquid chromatography-tandem mass spectrometry. The overexpression and purification of GroEL demonstrated that GroEL controlled the assembly of Bio-SeNPs both in vitro and in vivo. In vivo, oral administration of Bio-SeNPs could alleviate dextran sulfate sodium-induced colitis by decreasing cell apoptosis, increasing antioxidant capacity and the number of proliferating cells, and improving the function of the intestinal mucosal barrier. In vitro experiments verified that Bio-SeNPs inhibited lipopolysaccharide-induced toll-like receptor 4/NF-κB signaling pathway activation. These results suggest that the Bio-SeNPs with high stability could have potential as a nutritional supplement for the treatment of colitis in nanomedicine applications.

Amorphous structure and crystal stability determine the bioavailability of selenium nanoparticles

Microorganisms play a critical role in the biogeochemical cycling of selenium, often reducing selenite/selenate to elemental selenium nanoparticles (SeNPs). These SeNPs typically exist in an amorphous structure but can transform into a trigonal allotrope. However, the crystal structural transition process and its impact on selenium bioavailability have not been well studied. To shed light on this, we prepared chemosynthetic and biogenic SeNPs and investigated the stability of their crystal structure. We found that biogenic SeNPs exhibited a highly stable amorphous structure in various conditions, such as lyophilization, washing, and laser irradiation, whereas chemosynthetic SeNPs transformed into a trigonal structure in the same conditions. Additionally, a core-shell structure was observed in biogenic SeNPs after electron beam irradiation. Further analysis revealed that biogenic SeNPs showed a coordination reaction between Se atoms and surface binding biomacromolecules, indicating that the outer layer of Se-biomacromolecules complex prevented the SeNPs from crystallizing. We also investigated the effects of SeNPs crystal structures on the bioavailability in bacteria, yeast, and plants, finding that the amorphous structure of SeNPs determined Se bioavailability.

Unravelling the in vitro and in vivo potential of selenium nanoparticles in Alzheimer's disease: A bioanalytical review

Alzheimer's disease (AD) is a devastating neurodegenerative disorder characterized by progressive cognitive decline and the accumulation of beta-amyloid plaques and tau tangles in the brain. Current therapies have limited efficacy, prompting the search for novel treatments. Selenium nanoparticles (SeNPs) have emerged as promising candidates for AD therapy due to their unique physicochemical properties and potential therapeutic effects. This review provides an overview of SeNPs and their potential application in AD treatment, as well as the main bioanalytical techniques applied in this field. SeNPs possess antioxidant and anti-inflammatory properties, making them potential candidates to combat the oxidative stress and neuroinflammation associated with AD. Moreover, SeNPs have shown the ability to cross the blood-brain barrier (BBB), allowing them to target brain regions affected by AD pathology. Various methods for synthesizing SeNPs are explored, including chemical, physical and biological synthesis approaches. Based on the employment of algae, yeast, fungi, and plants, green methods offer a promising and biocompatible alternative for SeNPs production. In vitro studies have demonstrated the potential of SeNPs in reducing beta-amyloid aggregation and inhibiting tau hyperphosphorylation, providing evidence of their neuroprotective effects on neuronal cells. In vivo studies using transgenic mouse models and AD-induced symptoms have shown promising results, with SeNPs treatment leading to cognitive improvements and reduced amyloid plaque burden in the hippocampus. Looking ahead, future trends in SeNPs research involve developing innovative brain delivery strategies to enhance their therapeutic potential, exploring alternative animal models to complement traditional mouse studies, and investigating multi-targeted SeNPs formulations to address multiple aspects of AD pathology. Overall, SeNPs represent a promising avenue for AD treatment, and further research in this field may pave the way for effective and much-needed therapeutic interventions for individuals affected by this debilitating disease.

Antioxidant Metabolism Pathways in Vitamins, Polyphenols, and Selenium: Parallels and Divergences

Free radicals (FRs) are unstable molecules that cause reactive stress (RS), an imbalance between reactive oxygen and nitrogen species in the body and its ability to neutralize them. These species are generated by both internal and external factors and can damage cellular lipids, proteins, and DNA. Antioxidants prevent or slow down the oxidation process by interrupting the transfer of electrons between substances and reactive agents. This is particularly important at the cellular level because oxidation reactions lead to the formation of FR and contribute to various diseases. As we age, RS accumulates and leads to organ dysfunction and age-related disorders. Polyphenols; vitamins A, C, and E; and selenoproteins possess antioxidant properties and may have a role in preventing and treating certain human diseases associated with RS. In this review, we explore the current evidence on the potential benefits of dietary supplementation and investigate the intricate connection between SIRT1, a crucial regulator of aging and longevity; the transcription factor NRF2; and polyphenols, vitamins, and selenium. Finally, we discuss the positive effects of antioxidant molecules, such as reducing RS, and their potential in slowing down several diseases.

Green synthesis of biogenic selenium nanoparticles functionalized with ginger dietary extract targeting virulence factor and biofilm formation in Candida albicans

To treat the systemic infections caused by Candida albicans (C. albicans), various drugs have been used, however, infections still persisted due to virulence factors and increasing antifungal resistance. As a solution to this problem, we synthesized selenium nanoparticles (SeNPs) by using Bacillus cereus bacteria. This is the first study to report a higher (70 %) reduction of selenite ions into SeNPs in under 6 h. The as-synthesized, biogenic SeNPs were used to deliver bioactive constituents of aqueous extract of ginger for inhibiting the growth and biofilm (virulence factors) in C. albicans. UV-visible spectroscopy revealed a characteristic absorption at 280 nm, and Raman spectroscopy showed a characteristic peak shift at 253 cm-1 for the biogenic SeNPs. The synthesized SeNPs are spherical with 240-250 nm in size as determined by electron microscopy. Fourier transform infrared spectroscopy confirmed the functionalization of antifungal constituents of ginger over the SeNPs (formation of Ginger@SeNPs nanoconjugates). In contrast to biogenic SeNPs, nanoconjugates were active against C. albicans for inhibiting growth and biofilm formation. In order to reveal antifungal mechanism of nanoconjugates', real-time polymerase chain reaction (RT-PCR) analysis was performed, according to RT-PCR analysis, the nanoconjugates target virulence genes involved in C. albicans hyphae and biofilm formation. Nanoconjugates inhibited 25 % growth of human embryonic kidney (HEK) 293 cell line, indicating moderate cytotoxicity of active nanoconjugates in an in-vitro cytotoxicity study. Therefore, biogenic SeNPs conjugated with ginger dietary extract may be a potential antifungal agent and drug carrier for inhibiting C. albicans growth and biofilm formation.

Applications of peptide-functionalized or unfunctionalized selenium nanoparticles for the passivation of SARS-CoV-2 variants and the respiratory syncytial virus (RSV)

The SARS-CoV-2 Omicron subvariants BA.4, BA. 5 and XBB are currently causing a COVID resurgence due to their increased spreading and infectivity. These latest subvariants have been shown to be somewhat resistant to the most common vaccines even with the third dose. Moreover, it has been well documented that when patients stop taking some commercial therapies (such as Paxlovid), COVID from these variants may return and may even be more contagious. Herein, we tested unfunctionalized and functionalized selenium (Se) nanoparticles with three novel peptides (NapFFTLUFLTUTEKKKK, NapFFMLUFLMUMEKKKK, and NapFFSAVLQSGFKKKK) previously shown by themselves to passivate the Omicron SARS-CoV-2 BA.4, BA.5 and XBB variants. Se is a natural element in our diet and is well known to boost the immune system, thus, providing a complementary approach to viral infections. NapFFMLUFLMUMEKKKK showed a stronger inhibition ability at 98 % for Omicron BA.4 % and 96 % for Omicron BA.5 after just 15 min in vitro. Two types of Se nanoparticles (those made chemically or biogenically by cells) were tested to passivate the new SARS-CoV-2 XBB variant. Results showed that the combination of any peptide and using either type of Se NP, the Omicron subvariant XBB was inhibited by 100 % after just 15 min in vitro. Interestingly, the use of Se NPs alone outperformed the peptides in terms of XBB passivation. Also, in order to determine a mechanism of action, functionalizing Se nanoparticles with the NapFFSAVLQSGFKKKK peptide showed a high binding ability toward the chemotrypsin-like cysteine protease (SARS CoV-2 3CLpro). Further, as a demonstration of their versatility, these functionalized peptides also passivated the Respiratory Syncytial Virus (RSV). NapFFTLUFLTUTEKKKK and NapFFMLUFLMUMEKKKK showed in silico interactions with the fusion glycoprotein of RSV prompting in vitro RSV pseudo virus testing. Compared to the conventionally precipitated synthetic Se nanoparticles, in vitro results showed that biogenic Se functionalized with the peptides enhanced the inhibition RSV to 100 % after just 15 min of incubation. NapFFTLUFLTUTEKKKK and NapFFMLUFLMUMEKKKK also showed no potential genotoxicity or carcinogenic effects. The peptides showed good gastro-intestinal (GI) tract absorption and bioavailability as predicted using the partition coefficient (QP logPo/w), and high-water solubility as detected by QPlogS. According to these promising results, functionalizing biogenic Se nanoparticles with these novel peptides should be further studied in vivo for the improved diagnosis, prevention, and treatment of SARS-CoV-2, RSV, and other respiratory virus infections.

The Toxicological Assessment of Anoectochilus burmannicus Ethanolic-Extract-Synthesized Selenium Nanoparticles Using Cell Culture, Bacteria, and Drosophila melanogaster as Suitable Models

Selenium nanoparticles (SeNPs) are worthy of attention and development for nutritional supplementation due to their health benefits in both animals and humans with low toxicity, improved bioavailability, and controlled release, being greater than the Se inorganic and organic forms. Our previous study reported that Anoectochilus burmannicus extract (ABE)-synthesized SeNPs (ABE-SeNPs) exerted antioxidant and anti-inflammatory activities. Furthermore, ABE could stabilize and preserve the biological activities of SeNPs. To promote the ABE-SeNPs as supplementary and functional foods, it was necessary to carry out a safety assessment. Cytotoxicity testing showed that SeNPs and ABE-SeNPs were harmless with no killing effect on Caco2 (intestinal epithelial cells), MRC-5 (lung fibroblasts), HEK293 (kidney cells), LX-2 (hepatic stellate cells), and 3T3-L1 (adipocytes), and were not toxic to isolated human PBMCs and RBCs. Genotoxicity assessments found that SeNPs and ABE-SeNPs did not induce mutations in Salmonella typhimurium TA98 and TA100 (Ames test) as well as in Drosophila melanogaster (somatic mutation and recombination test). Noticeably, ABE-SeNPs inhibited mutation in TA98 and TA100 induced by AF-2, and in Drosophila induced by urethane, ethyl methanesulfonate, and mitomycin c, suggesting their anti-mutagenicity ability. This study provides data that support the safety and anti-genotoxicity properties of ABE-SeNPs for the further development of SeNPs-based food supplements.

Role of Nanoparticle-Conjugates and Nanotheranostics in Abrogating Oxidative Stress and Ameliorating Neuroinflammation

Oxidative stress is a deteriorating condition that arises due to an imbalance between the reactive oxygen species and the antioxidant system or defense of the body. The key reasons for the development of such conditions are malfunctioning of various cell organelles, such as mitochondria, endoplasmic reticulum, and Golgi complex, as well as physical and mental disturbances. The nervous system has a relatively high utilization of oxygen, thus making it particularly vulnerable to oxidative stress, which eventually leads to neuronal atrophy and death. This advances the development of neuroinflammation and neurodegeneration-associated disorders such as Alzheimer's disease, Parkinson's disease, epilepsy, dementia, and other memory disorders. It is imperative to treat such conditions as early as possible before they worsen and progress to irreversible damage. Oxidative damage can be negated by two mechanisms: improving the cellular defense system or providing exogenous antioxidants. Natural antioxidants can normally handle such oxidative stress, but they have limited efficacy. The valuable features of nanoparticles and/or nanomaterials, in combination with antioxidant features, offer innovative nanotheranostic tools as potential therapeutic modalities. Hence, this review aims to represent novel therapeutic approaches like utilizing nanoparticles with antioxidant properties and nanotheranostics as delivery systems for potential therapeutic applications in various neuroinflammation- and neurodegeneration-associated disease conditions.

Facile green synthesis and characterization of Terminalia arjuna bark phenolic-selenium nanogel: a biocompatible and green nano-biomaterial for multifaceted biological applications

Biogenic nanoparticle production is in demand as it is secure, has great promise, and is environmental friendly. This study aimed at green synthesis, characterization, and evaluation of Terminalia arjuna selenium nanoparticles (TA-SeNPs) for their antioxidant, antibacterial, anticancer activities, and their incorporation in gel for biomedical applications. The bio-reduction attributes of the T. arjuna (TA) bark extract were utilized to fabricate selenium nanoparticles. The TA bark extract is abundant in phenolics (193.63 ± 1.61 mg gallic acid equivalents/g), flavonoids (88.23 ± 0.39 mg quercetin equivalents/g), and tannins (109.46 ± 1.16 mg catechin equivalents/g), which perform as effective capping and stabilizing agents, thus enabling the fabrication of stable SeNPs. The fabrication of TA-SeNPs was corroborated by UV-visible spectra, which exhibited surface plasmon resonance at 291 nm. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) demonstrated nano-sized spherical TA-SeNPs with an average diameter ranging from 100 to 150 nm. Zeta potential analysis revealed that TA-SeNPs were negatively charged (-26.1 mV). X-ray diffraction presented amorphous TA-SeNPs with a quantification of 82.36 ± 10.2 μg/mL resulting from ICP-AES. The IC50 45.18 ± 0.11 μg/mL for the DPPH assay and 66.51% reducing power capacity values indicated that the TA-SeNPs possessed excellent radical scavenging efficacy. Moreover, the TA-SeNPs exhibited a broad spectrum of antimicrobial activity against potential pathogens. Additionally, the TA-SeNPs exhibited a dose-dependent cytotoxic effect on the MCF-7 breast cancer cell line, with an IC50 of 23.41 μg/mL. Furthermore, the TA-SeNP-incorporated gel showed excellent spreadability, extrudability, and consistency with retention of antimicrobial properties and hydrophilic contact angle. As an outcome, TA-SeNPs offer the possibility of the formulation and growth of sustainably designed green SeNPs that can be produced, conserved, and marketed securely across the globe.

Selenium-Fortified Kombucha-Pollen Beverage by In Situ Biosynthesized Selenium Nanoparticles with High Biocompatibility and Antioxidant Activity

Biogenic selenium nanoparticles (SeNPs) have been shown to exhibit increased bioavailability. Fermentation of pollen by a symbiotic culture of bacteria and yeasts (SCOBY/Kombucha) leads to the release of pollen content and enhances the prebiotic and probiotic effects of Kombucha. The aim of this study was to fortify Kombucha beverage with SeNPs formed in situ by Kombucha fermentation with pollen. Response Surface Methodology (RSM) was used to optimize the biosynthesis of SeNPs and the pollen-fermented Kombucha beverage. SeNPs were characterized by Transmission electron microscopy energy-dispersive X-ray spectroscopy (TEM-EDX), Fourier-transform infrared spectroscopy (FTIR), Dynamic light scattering (DLS), and Zeta potential. The pollen-fermented Kombucha beverage enriched with SeNPs was characterized by measuring the total phenolic content, antioxidant activity, soluble silicon, saccharides, lactic acid, and the total content of Se0. The polyphenols were identified by liquid chromatography-mass spectrometry (LC-MS). The pollen and the bacterial (nano)cellulose were characterized by scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX), FTIR, and X-Ray diffraction (XRD). We also assessed the in vitro biocompatibility in terms of gingival fibroblast viability and proliferation, as well as the antioxidant activity of SeNPs and the pollen-fermented Kombucha beverage enriched with SeNPs. The results highlight their increased biological performance in this regard.

Catechins and Selenium Species-How They React with Each Other

The combination of selenium and tea infusion, both with antioxidant properties, has potentially complementary mechanisms of action. Se-enriched tea has been considered as a possible Se supplement and a functional beverage to reduce the health risk of Se deficiency. This work investigated the interactions between plant catechins present in tea infusions and selenium species based on changes in the concentration of both reagents, their stability in aqueous solutions, and the possibilities of selenonanoparticles (SeNPs) formation. Selenium species exhibited instability both alone in their standard solutions and in the presence of studied catechins; selenocystine appeared as the most unstable. The recorded UV-Vis absorption spectra indicated the formation of SeNPs in the binary mixtures of catechins and selenite. SeNPs have also formed with diameters smaller than 100 nm when selenite and selenomethionine were added to tea infusions. This is an advantage from the point of view of potential medical applications.

A Review of the Antibacterial, Fungicidal and Antiviral Properties of Selenium Nanoparticles

The resistance of microorganisms to antimicrobial drugs is an important problem worldwide. To solve this problem, active searches for antimicrobial components, approaches and therapies are being carried out. Selenium nanoparticles have high potential for antimicrobial activity. The relevance of their application is indisputable, which can be noted due to the significant increase in publications on the topic over the past decade. This review of research publications aims to provide the reader with up-to-date information on the antimicrobial properties of selenium nanoparticles, including susceptible microorganisms, the mechanisms of action of nanoparticles on bacteria and the effect of nanoparticle properties on their antimicrobial activity. This review describes the most complete information on the antiviral, antibacterial and antifungal effects of selenium nanoparticles.

Selenium Nanoparticles as Potential Antioxidants to Improve Semen Quality in Boars

Selenium is an essential compound which can influence the fertility of boars by a greater margin. In past decades, research was mainly focused on a bioavailability of various selenium forms and the effect on semen quality. Recently, nanotechnology has expanded the possibilities of selenium supplementation research. Twenty-one Duroc boars (three groups with seven boars each) were included in this experiment with the first group being a control group with no selenium supplementation, and the second group being supplemented with 0.3 mg Se/kg of selenium in inorganic form of Na2SeO3. The third group was supplemented with selenium nanoparticles (100 nm) at the same dose as that of the second group. The experiment lasted for 126 days (three spermatogenesis cycles of boars) and the antioxidant parameters of boar semen were analysed at 42, 84 and 126 days, respectively. The antioxidant parameters (DPPH, FRAP, DMPD, GSH, GSSG) were not influenced by both Se2NO3 and selenium nanoparticle supplementation during this experiment. At the end of the monitored period, significantly higher (p < 0.004) antioxidant readings were observed by using the ABTS method but not the DPPH, DMPD and FRAP methods on the supplemented groups compared to the control. Moreover, selenium-nanoparticle-supplemented groups showed elevated glutathione peroxidase activity in the seminal fluid (p < 0.008). However, the selenium nanoparticle supplementation has not shown an improving effect on sperm quality. This could be considered as a safe alternative to inorganic selenium as well as having a potential to enhance the antioxidant properties of the semen of boars.

Pilot Study of Cytoprotective Mechanisms of Selenium Nanorods (SeNrs) under Ischemia-like Conditions on Cortical Astrocytes

The cytoprotective properties of the trace element selenium, its nanoparticles, and selenium nanocomplexes with active compounds are shown using a number of models. To date, some molecular mechanisms of the protective effect of spherical selenium nanoparticles under the action of ischemia/reoxygenation on brain cells have been studied. Among other things, the dependence of the effectiveness of the neuroprotective properties of nanoselenium on its diameter, pathways, and efficiency of penetration into astrocytes was established. In general, most research in the field of nanomedicine is focused on the preparation and study of spherical nanoparticles of various origins due to the ease of their preparation; in addition, spherical nanoparticles have a large specific surface area. However, obtaining and studying the mechanisms of action of nanoparticles of a new form are of great interest since nanorods, having all the positive properties of spherical nanoparticles, will also have a number of advantages. Using the laser ablation method, we managed to obtain and characterize selenium nanorods (SeNrs) with a length of 1 μm and a diameter of 100 nm. Using fluorescence microscopy and inhibitory analysis, we were able to show that selenium nanorods cause the generation of Ca2+ signals in cortical astrocytes in an acute experiment through the mobilization of Ca2+ ions from the thapsigargin-sensitive pool of the endoplasmic reticulum. Chronic use of SeNrs leads to a change in the expression pattern of genes encoding proteins that regulate cell fate and protect astrocytes from ischemia-like conditions and reoxygenation through the inhibition of a global increase in the concentration of cytosolic calcium ([Ca2+]i). An important component of the cytoprotective effect of SeNrs during ischemia/reoxygenation is the induction of reactive A2-type astrogliosis in astrocytes, leading to an increase in both baseline and ischemia/reoxygenation-induced phosphoinositide 3-kinase (PI3K) activity and suppression of necrosis and apoptosis. The key components of this cytoprotective action of SeNrs are the actin-dependent process of endocytosis of nanoparticles into cells and activation of the Ca2+ signaling system of astrocytes.