Nano-Se as a novel candidate in the management of oxidative stress related disorders and cancer

A new selenium nanomaterial: structural insights, nonlinear optical properties (DFT study), and biological potential

CONTEXT

This study investigates the synthesis, structural characteristics, thermal properties, and biological activity of the double selenate salt Na2Cd(SeO4)2·2H2O. The synthesis of this compound was driven by the need for novel materials with potential applications in medicinal chemistry and materials science. The structural integrity and physicochemical properties of Na2Cd(SeO4)2·2H2O were confirmed through a series of characterization techniques, including FT-IR spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic light scattering (DLS), and zeta potential measurements. The thermal behavior of the compound, exhibiting a multi-stage decomposition pattern, provides important insights into its stability and transformation mechanisms, essential for its potential use in various applications. Biological testing, conducted on the HepG2 liver cancer cell line, revealed a dose-dependent cytotoxic effect, with morphological changes and cytoskeletal disruption at higher concentrations, highlighting the compound's anticancer potential. The compound also demonstrated a high zeta potential, indicating good colloidal stability and suggesting favorable bioavailability. These findings underscore the relevance of Na2Cd(SeO4)2·2H2O for biomedical applications, particularly in anticancer therapies, where its unique combination of properties may offer therapeutic advantages.

METHODS

Quantum chemical calculations were performed using density functional theory (DFT) to gain insights into the electronic structure, molecular geometry, and nonlinear optical (NLO) properties of Na2Cd(SeO4)2·2H2O. Molecular electrostatic potential (MEP) mapping revealed nucleophilic and electrophilic activity regions, pointing to possible reactive sites. Frontier molecular orbital (FMO) analysis indicated a moderate HOMO-LUMO energy gap, suggesting a balance between stability and reactivity. Thermal decomposition stages were characterized using TGA and DSC, with identifiable mass loss steps corresponding to water release and selenium dioxide formation. In vitro biological evaluation was conducted on HepG2 cells using MTT assays, immunofluorescence staining, and morphological analysis. The IC₅₀ value was established at approximately 0.05 µg/ml. Zeta potential and DLS analyses were employed to assess colloidal behavior and particle distribution. Together, these methodologies support the promising physicochemical and biological profile of Na2Cd(SeO4)2·2H2O, justifying its further investigation for nanomedicine and drug delivery applications.

Selenium nanoparticles in aquaculture: Unique advantages in the production of Se-enriched grass carp (Ctenopharyngodon idella)

The production of selenium-enriched fish can contribute to alleviating selenium deficiency in human diets. However, it is still unclear which selenium source, as an additive, can efficiently and cost-effectively produce high-quality selenium-enriched fish. This study evaluated the effects of selenium nanoparticles (SeNP), selenite, and selenomethionine (SeMet) on the growth, antioxidant capacity, selenium content, selenium speciation, and meat quality of grass carp. Ten diets were prepared, including a basal diet (BD) and three concentrations (0.1, 0.3, and 0.9 mg/kg) of SeNP, selenite, and SeMet. A total of 600 fish (250.79 ± 1.57 g) were randomly assigned to 30 tanks (3 tanks/group). Fish were fed the experimental diet three times daily for 60 d. In this study, SeNP most significantly promoted the growth and antioxidant capacity of grass carp, with 0.3 mg/kg SeNP identified as the optimal additive concentration. Additionally, SeNP demonstrated equally excellent bioavailability as SeMet and significantly increased the content of SeMet in grass carp (Ctenopharyngodon idella) muscle. Furthermore, compared to SeMet and selenite, dietary SeNP could more significantly enhance the content of selenocysteine (SeCys2) and methylselenocysteine (MeSeCys) in grass carp muscle tissue. In addition, we have demonstrated that SeCys2 and MeSeCys promote apoptosis of cancer cells (HeLa) through the mitochondrial apoptotic pathway (involving Bax and Bcl-2). Furthermore, as an additive, 0.3 mg/kg SeNP significantly improved the flesh quality of grass carp by reducing crude fat and heavy metal content, as well as increasing the levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and the ratio of n-3/n-6 polyunsaturated fatty acid (PUFA). In summary, SeNP is the most suitable additive for producing selenium-enriched fish.

Selenite bioreduction with concomitant green synthesis of selenium nanoparticles by a selenite resistant EPS and siderophore producing terrestrial bacterium

Environmental bacterial isolates play a very important role in bioremediation of metals and toxic metalloids. A bacterial strain with high selenite (SeO32-) tolerance and reducing capability was isolated from electronic waste dump site in Banaras Hindu University, Varanasi, India. Based on 16 S rRNA sequencing and BLAST search, this bacterial isolate was identified as Bacillus paramycoides and designated as strain MF-14. It tolerated Sodium selenite up to 110 mM when grown aerobically in LB broth and reduced selenite into elemental selenium (Se0) significantly within 24 h with concomitant biosynthesis of selenium nanoparticles as clearly revealed by brick red precipitate and specific surface plasmon resonance peak at 210 nm using UV-Visible spectrophotometer. Scanning electron microscopy (SEM) analysis of this bacterial strain exposed to 1mM and 5 mM selenite also demonstrated morphological alterations as cell enlargement due to accumulation and bioprecipitation of elemental selenium (Se0). The FTIR analysis clearly demonstrated that functional groups present on the surface of biogenic selenium nanoparticles (SeNPs) play a significant role in the stabilization and capping of SeNPs. Furthermore, these SeNPs were characterized using spectroscopic analysis involving Dynamic light scattering, zeta potential, XPS, FTIR, XRD and Raman spectroscopy which clearly revealed particle size 10-700 nm, amorphous nature, stability as well as it's oxidation state. The biochemical studies have demonstrated that membrane bound reductase enzyme may be responsible for significant reduction of selenite into elemental selenium. Therefore, we may employ Bacillus paramycoides strain MF-14 successfully for bioremediation of selenite contaminated environmental sites with concomitant green synthesis of SeNPs.

Folate-Targeted Transgenic Activity of Dendrimer Functionalized Selenium Nanoparticles In Vitro

Current chemotherapeutic drugs, although effective, lack cell-specific targeting, instigate adverse side effects in healthy tissue, exhibit unfavourable bio-circulation and can generate drug-resistant cancers. The synergistic use of nanotechnology and gene therapy, using nanoparticles (NPs) for therapeutic gene delivery to cancer cells is hereby proposed. This includes the benefit of cell-specific targeting and exploitation of receptors overexpressed in specific cancer types. The aim of this study was to formulate dendrimer-functionalized selenium nanoparticles (PAMAM-SeNPs) containing the targeting moiety, folic acid (FA), for delivery of pCMV-Luc-DNA (pDNA) in vitro. These NPs and their gene-loaded nanocomplexes were physicochemically and morphologically characterized. Nucleic acid-binding, compaction and pDNA protection were assessed, followed by cell-based in vitro cytotoxicity, transgene expression and apoptotic assays. Nanocomplexes possessed favourable sizes (<150 nm) and ζ-potentials (>25 mV), crucial for cellular interaction, and protected the pDNA from degradation in an in vivo simulation. PAMAM-SeNP nanocomplexes exhibited higher cell viability (>85%) compared to selenium-free nanocomplexes (approximately 75%), confirming the important role of selenium in these nanocomplexes. FA-conjugated PAMAM-SeNPs displayed higher overall transgene expression (HeLa cells) compared to their non-targeting counterparts, suggesting enhanced receptor-mediated cellular uptake. Overall, our results bode well for the use of these nano-delivery vehicles in future in vivo studies.

Prevention of Hepatic Ischemia-Reperfusion Injury by Carbohydrate-Derived Nanoantioxidants

Hepatic ischemia-reperfusion injury (IRI), which mainly results from excessive reactive oxygen species (ROS) generated by a reperfusion burst of oxygen, has long been a major cause of liver dysfunction and failure after surgical procedures. Here, a monodispersed hydrophilic carbohydrate-derived nanoparticle (C-NP) was synthesized as a nanoantioxidant that could effectively prevent hepatic IRI. The spherical C-NPs had a size of ∼78 ± 11.3 nm covered with polar surface groups. They were well dispersible in water with good colloidal stability, nontoxicity, and good ROS scavenging capability. The C-NPs also exhibited good circulation lifetime, effective delivery to liver, and gradual degradability with an ability to assist the IRI group maintaining a normal and healthy liver status. The pathology mechanism of C-NPs in hepatic IRI was confirmed to be scavenging of excessive ROS by C-NPs. The effective therapeutic treatment of C-NPs in living animals revealed a great potential in clinical prevention for hepatic IRI.

Anti-leukemia activities of selenium nanoparticles embedded in nanotube consisted of triple-helix β-d-glucan

Acute myeloid leukemia (AML) is a difficult therapeutic hematological tumor. It is urgent to find a non-toxic natural drug to treat AML. Herein, the selenium nanoparticles (SeNPs) embedded in nanotubes consisted of triple helix β-(1, 3)-d-glucan (BFP) from the black fungus that were wrapped to form stable inclusion complex BFP-Se, which was self-assembled and exhibited high stability in water. In vitro, the BFP-Se significantly inhibited the proliferation of AML cells and increased the cytotoxicity on AML cells. On single-cell levels, the U937 cells were gradually swelled and lysed with BFP-Se treatment on optofluidics chips. Further, the blood and bone marrow analysis indicated the anti-leukemia effects of BFP-Se in vivo. Moreover, BFP-Se increased the total antioxidant capacity of AML cells and decreased the expression of c-Jun activation domain-binding protein 1 and thioredoxin 1. Our results suggest that this biocompatible polysaccharide nanotube containing Se nanoparticles would provide a novel strategy for AML therapy.

Selenium involvement in mitochondrial function in thyroid disorders

Selenium (Se), an important oligoelement, is a component of the antioxidant system. Over the last decade, it has been ever more frequently discussed in the context of thyroid disorders. Graves' disease and Hashimoto's thyroiditis, differentiated thyroid cancer, and even endemic goiter may have common triggers that are activated by excess reactive oxygen species (ROS), which are involved in various stages of the pathogenesis of thyroid disorders. Most oxidative events occur in mitochondria, organelles that contain enzymes with Se as a cofactor. Mitochondria are responsible for the production of ATP in the cell and are also a major site of ROS production. Thyroid hormone status (the thyroid being the organ with the highest concentration of Se in the body) has a profound impact on mitochondria biogenesis. In this review, we focus on the role of Se in mitochondrial function in thyroid disorders with impaired oxidative stress, since both thyroid hormone synthesis and thyroid dysfunction involve ROS. The role of Se deficiency or its excess in relation to mitochondrial dysfunction in the context of thyroid disorders is therefore of interest.

Selenite Reduction and the Biogenesis of Selenium Nanoparticles by Alcaligenesfaecalis Se03 Isolated from the Gut of Monochamus alternatus (Coleoptera: Cerambycidae)

In this study, a bacterial strain exhibiting high selenite (Na₂SeO₃) tolerance and reduction capacity was isolated from the gut of Monochamus alternatus larvae and identified as Alcaligenes faecalis Se03. The isolate exhibited extreme tolerance to selenite (up to 120 mM) when grown aerobically. In the liquid culture medium, it was capable of reducing nearly 100% of 1.0 and 5.0 mM Na₂SeO₃ within 24 and 42 h, respectively, leading to the formation of selenium nanoparticles (SeNPs). Electron microscopy and energy dispersive X-ray analysis demonstrated that A. faecalis Se03 produced spherical electron-dense SeNPs with an average hydrodynamic diameter of 273.8 ± 16.9 nm, localized mainly in the extracellular space. In vitro selenite reduction activity and real-time PCR indicated that proteins such as sulfite reductase and thioredoxin reductase present in the cytoplasm were likely to be involved in selenite reduction and the SeNPs synthesis process in the presence of NADPH or NADH as electron donors. Finally, using Fourier-transform infrared spectrometry, protein and lipid residues were detected on the surface of the biogenic SeNPs. Based on these observations, A. faecalis Se03 has the potential to be an eco-friendly candidate for the bioremediation of selenium-contaminated soil/water and a bacterial catalyst for the biogenesis of SeNPs.

Antioxidant nanomaterials in advanced diagnoses and treatments of ischemia reperfusion injuries

Organ ischemia with inadequate oxygen supply followed by reperfusion (which initiates a complex of inflammatory responses and oxidative stress) occurs in different clinical conditions and surgical procedures including stroke, myocardial infarction, limb ischemia, renal failure, organ transplantation, free-tissue-transfer, cardiopulmonary bypass, and vascular surgery. Even though pharmacological treatments protect against experimental ischemia reperfusion (I/R) injury, there has not been enough success in their application for patient benefits. The main hurdles in the treatment of I/R injury are the lack of diagnosis tools for understanding the complicated chains of I/R-induced signaling events, especially in the acute phase after ischemia, determining the affected regions of the tissue over time, and then, targeting and safe delivery of antioxidants, drugs, peptides, genes and cells to the areas requiring treatment. Besides the innate antioxidant and free radical scavenging properties, some nanoparticles also show higher flexibility in drug delivery and imaging. This review highlights three main approaches in nanoparticle-mediated targeting of I/R injury: nanoparticles (1) as antioxidants for reducing tissue oxidative stress, (2) for targeted delivery of therapeutic agents to the ischemic regions or cells, and (3) for imaging I/R injury at the molecular, cellular or tissue level and monitoring its evolution using contrasts induced by nanoparticles. These approaches can also be combined to realize so called theranostics for providing simultaneous diagnosis of ischemic regions and treatments by targeted delivery.