Biogenic synthesis of selenium nanoparticles and their effect on As(III)-induced toxicity on human lymphocytes

Chemopreventive mechanism of action by oxidative stress and toxicity induced surface decorated selenium nanoparticles

BACKGROUND

Scientists are working on creating novel materials that can help in the treatment of diverse cancer-related diseases having trademark highlights like the target siting, specificity, improved therapeutic index of radiotherapy and chemotherapeutic treatments. The utilization of novel nanomaterials which are surface adorned with drugs or natural compounds can be used in diverse medical applications and helps in setting up a new platform for its improvement in the chemotherapeutic potentiality. One such nanomaterial is the trace element selenium in its nanoparticulate form that has been proved to be a potential chemotherapeutic agent recently.

METHODS

The English language papers were gathered from electronic databases like Sciencedirect, Pub Med, Google Scholar and Scopus, the papers are published from 2001 to 2019.

RESULTS

In the initial phase, approximately 200 papers were searched upon, out of which 118 articles were included after screening and critical reviewing. The information included was also tabulated for better knowledge and easy read. These articles contain information on the nanotechnology, inflammation, cancer and selenium as nanoparticles.

CONCLUSION

The overview of the paper explains the enhancement of potentiality of anticancer drugs or phytochemicals which restricts its utilization in chemotherapeutic applications by the encapsulation or adsorption of them on selenium nanoparticles proven to accelerate the anticancerous properties with better results when compared with individual components. SeNPs (selenium nanoparticles) have demonstrated chemotherapeutic activity due to pro-oxidant property, where the anti-oxidant enzymes are stimulated to produce reactive active species, which induces oxidative stress, followed by activation of the apoptotic signalling pathway, cell cycle arrest, mitochondrial dysfunction and other pathways that ultimately lead to cell death. Selenium in nanoparticulate form can be used as a micronutrient to human health, thereby having low toxicity, can easily be degraded and also has good biocompatibility.

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.

Genoprotective activities of plant natural substances in cancer and chemopreventive strategies in the context of 3P medicine

Severe durable changes may occur to the DNA structure caused by exogenous and endogenous risk factors initiating the process of carcinogenesis. By evidence, a large portion of malignancies have been demonstrated as being preventable. Moreover, the targeted prevention of cancer onset is possible, due to unique properties of plant bioactive compounds. Although genoprotective effects of phytochemicals have been well documented, there is an evident lack of articles which would systematically present the spectrum of anticancer effects by phytochemicals, plant extracts, and plant-derived diet applicable to stratified patient groups at the level of targeted primary (cancer development) and secondary (cancer progression and metastatic disease) prevention. Consequently, clinical implementation of knowledge accumulated in the area is still highly restricted. To stimulate coherent co-development of the dedicated plant bioactive compound investigation on one hand and comprehensive cancer preventive strategies on the other hand, the current paper highlights and deeply analyses relevant evidence available in the area. Key molecular mechanisms are presented to detail genoprotective and anticancer activities of plants and phytochemicals. Clinical implementation is discussed. Based on the presented evidence, advanced chemopreventive strategies in the context of 3P medicine are considered.

Gentamicin-Assisted Mycogenic Selenium Nanoparticles Synthesized Under Gamma Irradiation for Robust Reluctance of Resistant Urinary Tract Infection-Causing Pathogens

The purpose of this research is to compare and enhance the antimicrobial and antibiofilm potentials of the biogenic selenium nanoparticles (Se NPs) produced by cost-effective and eco-friendly green methods. The synthesis of Se NPs is described in this manuscript by two different methods: a biogenic process using Penicillium chrysogenum filtrate and by utilizing gentamicin drug (CN) following the application of gamma irradiation. Se NPs were characterized by UV-Vis., HRTM, FTIR, XRD, DLS, SEM, and EDX mapping technique. Antimicrobial and antibiofilm activities of the synthesized Se NPs were investigated against multidrug-resistant (MDR) bacteria and yeast causing severe diseases such as urinary tract infection (UTI). The biogenic Se NPs exhibited an absorption peak at 435.0 nm while Se NPs-CN showed an absorption peak at 350.0 nm which is related to the surface plasmon resonance (SPR). Data obtained from HRTEM, SEM/mapping, and XRD analysis confirmed the mono-dispersion and crystalline nature of the prepared samples with an average diameter of 33.84 nm and 22.37 nm for the mycogenic Se NPs and Se NPs-CN, respectively. The synthesized Se NPs-CN possesses an encouraging antimicrobial potential with respect to the biogenic Se NPs against all examined UTI-causing microbes. Remarkably, Se NPs-CN showed antimicrobial potential toward Candida albicans with a zone of Inhibition (ZOI) recorded at 26.0 mm, 23.0 mm ZOI for Escherichia coli and 20.0 mm ZOI against Staphylococcus aureus. In addition, the incorporated Se NPs-CN displayed an enhanced percentage of biofilm inhibition of 88.67%, 87.93%, and 85.20% against S. aureus, P. aeruginosa, and E. coli, respectively. Accordingly, the novelty of the present research involves the green synthesis of mono-dispersed Se NPs and combining the synergistic potential of CN with Se NPs for potential biomedical, pharmaceutical, and therapeutic applications especially in the treatment of UTI. Graphical Abstract.

Polymerized Selenium Nanoparticles for Folate-Receptor-Targeted Delivery of Anti-Luc-siRNA: Potential for Gene Silencing

The development of a biocompatible and nontoxic gene delivery vehicle remains a challenging task. Selenium nanoparticles (SeNPs) have the potential to increase delivery efficiency, to reduce side effects, and to improve therapeutic outcomes. In this study, chitosan (Ch) functionalized folate (FA)-targeted SeNPs were synthesized, characterized, and evaluated for their potential to bind, protect, and safely deliver Fluc-siRNA in vitro. SeNPs of less than 100 nm were successfully synthesised and further confirmed using UV-vis and Fourier transform infrared spectroscopy, transmission electron microscopy, and nanoparticle tracking analysis. Cell viability studies were conducted in vitro in selected cancer and non-cancer cell lines. Folate receptor (FOLR1) targeted and nontargeted luciferase gene silencing studies were assessed in the transformed Hela-tat-Luc cell line expressing the luciferase gene. Targeted and nontargeted SeNP nanocomplexes showed minimal toxicity in all cell lines at selected w/w ratios. Maximum gene silencing was achieved at optimum w/w ratios for both nanocomplexes, with Selenium-chitosan-folic acid (SeChFA) nanocomplexes showing slightly better transgene silencing, as supported by results from docking studies showing that SeChFA nanocomplexes interacted strongly with the folate receptor (FOLR1) with high binding energy of -4.4 kcal mol-1.

Sustainable approach to almond skin mediated synthesis of tunable selenium microstructures for coating cotton fabric to impart specific antibacterial activity

Currently, the synthesis of nanostructured inorganic materials with tunable morphology is still a great challenge. In this study, almond skin extract was employed for the biogenic synthesis of selenium nanoparticles with tunable morphologies such as rods and brooms. The effects of various synthesis parameters on morphologies were investigated using UV-Visible spectroscopy and scanning electron microscopy (SEM) which indicated that selenium brooms (SeBrs) were best synthesized using almond skin extract and optimized conditions of SeO₂, ascorbic acid, pH, incubation temperature and time. Based on these results, the mechanism of SeBrs synthesis is proposed as having involved four stages such as nucleation, self-assembly, Ostwald ripening, and decomposition. Further, the test of antibacterial activity together with minimum inhibitory concentrations and minimum bactericidal concentrations indicated the selective, specific and good activity against B. subtilis. In addition, in situ coating of SeBrs on cotton fabric and its investigation by SEM demonstrated successful coating. Evident from plate-based assay and study of growth kinetics, coated fabric exhibited excellent anti-B. subtilis activity which demonstrated that biogenic SeBrs can be employed to coat cotton fabrics that can be used in operation theatres to reduce the episodes of Bacillus related Bacteraemia.

Enhanced Antimicrobial and Cytotoxicity on Cancer Cell using Bio-Originated Selenium Nanoparticles

Present work describes the bio-originated synthesis of selenium nanoparticles using seed extract of Cassia angustifolia. The biological macromolecules in seed extract react with metal ions to generate selenium nanoparticles. The seed extract acts as reducing, capping and stabilizing agents. The selenium nanoparticles produced by the plant extract are amorphous, nearly spherical in shape and held together by protein coating in a range of about 80-100 nm in size, under ambient conditions. The structural properties of selenium nanoparticles were characterized by UV-visible spectroscopy, FTIR, XRD, FESEM with EDAX, HRTEM and AFM. Antibacterial and antifungal activity of selenium nanoparticles were tested against four bacterial and two fungal strains using standard agar-well diffusion method. The zone of inhibition was observed in the selenium nanoparticles against different microbes and suggested that the bio-originated selenium nanoparticles act as an effective antibacterial and antifungal agent, so it has a great latent in the preparation of drugs used against pathogenic diseases. The cytotoxicity of bio-originated selenium nanoparticles was tested under in vitro conditions on Vero cell line and had compared with MDA-MB231 cancer cell line at different concentrations and the results had proved that bio-originated synthesis selenium nanoparticles can inhibit the growth of human breast-cancer cells by concentration-dependent manner.

The Role of Selenium in Arsenic and Cadmium Toxicity: an Updated Review of Scientific Literature

Arsenic (As) and cadmium (Cd) are elements arousing major public health concerns associated with environmental pollution, high toxicity potential, and carcinogenic nature. However, selenium (Se) at low doses and incorporated into enzymes and proteins has antioxidant properties and protects animals and humans from the risk of various diseases. It also has an exceptionally narrow range between necessary and toxic concentrations, which is a well-known hindrance in its use as a dietary supplement. The present article aims to update and expand the role of Se in As and Cd toxicity discussed in our earlier paper. In general, recent reports show that Se, regardless of its form (as selenite, selenomethionine, nanoSe, or Se from lentils), can reduce As- or Cd-mediated toxicity in the liver, kidney, spleen, brain, or heart in animal models and in cell culture studies. As was suggested in our earlier review, Se antagonizes the toxicity of As and Cd mainly through sequestration of these elements into biologically inert complexes and/or through the action of Se-dependent antioxidant enzymes. An increase in the As methylation efficiency is proposed as a possible mechanism by which Se can reduce As toxicity. However, new studies indicate that Se may also diminish As or Cd toxicity by activation of the Nrf2 pathway. In addition, this paper discusses possible signs of Se toxic effects, which may be a challenge for its future use in the therapy of As and Cd poisoning and provide future directions to address this issue.

Factorial design-optimized and gamma irradiation-assisted fabrication of selenium nanoparticles by chitosan and Pleurotus ostreatus fermented fenugreek for a vigorous in vitro effect against carcinoma cells

The novelty of the present work looks in the synthesis of aqueous dispersed selenium nanoparticles (Se NPs) using gamma rays with the aid of various natural macromolecules such as citrus pectin (CP), sodium alginate (Alg), chitosan (CS) and aqueous extract of fermented fenugreek powder (AEFFP) using Pleurotus ostreatus for investigating their impact in vitro toward carcinoma cell. The synthesized Se NPs were characterized by XRD, UV-Vis., DLS, HRTEM, SEM, EDX and FTIR. Nucleation and growth mechanisms were also discussed. The factorial design was applied to examine the importance of multiple parameters on Se NPs production with a special focus on temperature and gamma rays influences. FTIR spectrum exhibited the existence of several functional groups in Se NPs-capping macromolecules. Results revealed that Se NPs' size was dramatically-influenced by the type of stabilizer, precursors concentration, pH and the absorbed gamma rays dose. The current research reported the promising antitumor application of Se NPs against Ehrlich Ascites Carcinoma (EAC) and human Colon Adenocarcinoma (CACO) in vitro. The proliferation of EAC was significantly-hindered by Se NPs-CS (38.0 μg/ml) at 60 kGy (IC₅₀ = 23.12%) and Se NPs-AEFFP (19.00 μg/ml) at 15 kGy (IC₅₀ = 7.21%). Also, Se NPs control the generation of CACO cells, IC₅₀ was recorded as 25.32% for Se NPs-CS (38.0 μg/ml) and 8.57% for Se NPs-AEFFP (19.00 μg/ml).

Biosynthesis of Selenium Nanoparticles using yeast Nematospora coryli and examination of their anti-candida and anti-oxidant activities

Selenium (Se) is a rare and essential element for the human body and other living organisms because of its role in the structure of several proteins and having anti-oxidant properties to reduce oxidative stress at cells. Some microorganisms can absorb Se oxyanions and convert them into zero-valent Se (Se0) in the nanoscale dimensions, which can be used for producing Se nanoparticles (SeNPs). In the present study, SeNPs were intracellularly biosynthesised by yeast Nematospora coryli, which is an inexpensive method and does not involve using materials hazardous for human and environment. The produced NPs were refined by a two-phase system and then characterised and identified by ultraviolet-visible, X-ray diffraction, X-ray fluorescence, transmission electron microscope, and Fourier transform infrared spectroscopy analyses. The structural analysis of biosynthesised SeNPs showed spherical-shaped NPs with size ranging from 50 to 250 nm. Also, extracted NPs were applied to explore their anti-candida and anti-oxidant activities. The results of this investigation confirm the biological properties of Se.

A Systematic Review of the Genotoxicity and Antigenotoxicity of Biologically Synthesized Metallic Nanomaterials: Are Green Nanoparticles Safe Enough for Clinical Marketing?

Background and objectives: Although studies have elucidated the significant biomedical potential of biogenic metallic nanoparticles (MNPs), it is very important to explore the hazards associated with the use of biogenic MNPs. Evidence indicates that genetic toxicity causes mutation, carcinogenesis, and cell death. Materials and Methods: Therefore, we systematically review original studies that investigated the genotoxic effect of biologically synthesized MNPs via in vitro and in vivo models. Articles were systematically collected by screening the literature published online in the following databases; Cochrane, Web of Science, PubMed, Scopus, Science Direct, ProQuest, and EBSCO. Results: Most of the studies were carried out on the MCF-7 cancer cell line and phytosynthesis was the general approach to MNP preparation in all studies. Fungi were the second most predominant resource applied for MNP synthesis. A total of 80.57% of the studies synthesized biogenic MNPs with sizes below 50 nm. The genotoxicity of Ag, Au, ZnO, TiO₂, Se, Cu, Pt, Zn, Ag-Au, CdS, Fe₃O₄, Tb₂O₃, and Si-Ag NPs was evaluated. AgNPs, prepared in 68.79% of studies, and AuNPs, prepared in 12.76%, were the two most predominant biogenic MNPs synthesized and evaluated in the included articles. Conclusions: Although several studies reported the antigenotoxic influence of biogenic MNPs, most of them reported biogenic MNP genotoxicity at specific concentrations and with a dose or time dependence. To the best of our knowledge, this is the first study to systematically evaluate the genotoxicity of biologically synthesized MNPs and provide a valuable summary of genotoxicity data. In conclusion, our study implied that the genotoxicity of biologically synthesized MNPs varies case-by-case and highly dependent on the synthesis parameters, biological source, applied assay, etc. The gathered data are required for the translation of these nanoproducts from research laboratories to the clinical market.

Nano-selenium attenuates nickel-induced testosterone synthesis disturbance through inhibition of MAPK pathways in Sprague-Dawley rats

The aim of this study was to investigate the protective effects of Nano-Se against Ni-induced testosterone synthesis disorder in rats and determine the underlying protective mechanism. Sprague-Dawley rats were co-treated with Ni (5.0 mg/kg, i.p.) and Nano-Se (0.5, 1.0, and 2.0 mg/kg, oral gavage) for 14 days after which various endpoints were evaluated. The Ni-induced abnormal pathological changes and elevated 8-OHdG levels in the testes were attenuated by Nano-Se administration. Importantly, decreased serum testosterone levels in the Ni-treated rats were significantly restored by Nano-Se treatment, particularly at 1.0 and 2.0 mg/kg. Furthermore, the mRNA and protein levels of testosterone synthetase were increased by Nano-Se compared to the Ni group, whereas phosphorylated protein expression levels of mitogen-activated protein kinase (MAPK) pathways were suppressed by Nano-Se administration in the Ni-treated rats. Overall, the results suggest that Nano-Se may ameliorate the Ni-induced testosterone synthesis disturbance via the inhibition of ERK1/2, p38, and JNK MAPK pathways.

In vitro and in vivo toxicity assessment of selenium nanoparticles with significant larvicidal and bacteriostatic properties

In the present study, we investigated the larvicidal and bacteriostatic activity of biosynthesized selenium nanoparticles using aqueous berry extract of Murraya koenigii (Mk-Se NPs). The synthesized Mk-Se NPs were characterized using UV-visible spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis. XRD analysis revealed the crystalline nature of Mk-Se NPs as hexagonal. The FTIR spectra of Mk-Se NPs exhibited a strong peak at 3441 cm^-1 corresponding to the OH group. SEM and TEM analysis showed that the Mk-Se NPs were spherical in shape with a size between 50 and 150 nm. EDX peaks confirm the presence of 73.38% of selenium and 26.62% of oxide in Mk-Se NPs. Mk-Se NPs showed significant larvicidal property against the 4th instar larvae of a dengue fever-causing vector Aedes aegypti with LC_50- - 3.54 μg mL^-1 and LC_90- - 8.128 μg mL^-1 values. Mk-Se NPs displayed anti-bacterial activity against Gram-positive (Enterococcus faecalis &Streptococcus mutans) and Gram-negative (Shigella sonnei &Pseudomonas aeruginosa) bacteria at 40 and 50 μg mL^-1. In addition, Mk-Se NPs reduced bacterial biofilm thickness extensively at 25 μg mL^-1. The high antioxidant property at 50 μg mL^-1 and low hemolysis activity till 100 μg mL^-1 proved the biocompatible nature of Mk-Se NPs. In vitro and in vivo toxicity assessment of Mk-Se NPs showed low cytotoxicity against RAW 264.7 macrophages and Artemia nauplii. Together, our results suggest the potential application of Mk-Se NPs as a nano-biomedicine.

Phytofabrication of Selenium Nanoparticles From Emblica officinalis Fruit Extract and Exploring Its Biopotential Applications: Antioxidant, Antimicrobial, and Biocompatibility

In the present study, phytofabricated selenium nanoparticles (PF-SeNPs) were prepared from aqueous fruit extract of Emblica officinalis in a facile, green, economic, tactic and eco-friendly way. The aqueous fruit extract of E. officinalis was found to be rich with various secondary metabolites including phenolics (59.18 ± 2.91 mg gallic acid equivalents/g), flavonoids (38.50 ± 2.84 mg catechin equivalents/g), and tannins (44.28 ± 3.09 mg tannic acid equivalents/g) and determined that highly appropriate for the biosynthesis of nanoparticles. The facile phytofabrication of PF-SeNPs was confirmed by UV-visible and FTIR spectroscopic analysis. The XRD pattern and Raman spectroscopy showed that synthesized PF-SeNPs were amorphous in nature. The Zeta potential analysis confirmed that PF-SeNPs were negatively charged (-24.4 mV). The DLS analysis revealed that PF-SeNPs were in nano size and less aggregated with poly-dispersity index of less than 0.2. The SEM images depicted that PF-SeNPs were spherical in shape. The EDX analysis revealed that PF-SeNPs were constituted with Se (61.60%), C (29.96%), and O (4.41%). The HR-TEM analysis determined that PF-SeNPs were in nano size with an average diameter of 15–40 nm. The PF-SeNPs have offered fascinating bio-potential applications, such as antioxidant, antimicrobial and biocompatibility. They have also exhibited dose-dependent free radical scavenging activity, and EC50 was determined as 15.67 ± 1.41 and 18.84 ± 1.02 μg/mL for DPPH and ABTS assays, respectively. The PF-SeNPs has also shown the wide range of antimicrobial activity on foodborne pathogens, and it was found to be highly efficient on fungi followed by Gram-positive and Gram-negative bacteria. The biocompatibility of PF-SeNPs was assessed in N2a cells with much higher IC50 value (dose required to inhibit 50% of cell viability) compared to sodium selenite. Also, mitochondrial membrane potential (MMP) and caspase-3 were much less altered on treatment of PF-SeNPs related to sodium selenite. The cytotoxic studies clearly determined that PF-SeNPs was much less toxic and safer related to sodium selenite. Thus, PF-SeNPs could find suitable application as antioxidant and antimicrobial agent in food, biomedical, and pharmaceutical industry.

Selenium as a pleiotropic agent for medical discovery and drug delivery

Selenium as a biologically active element lends much support to health maintenance and disease prevention. It is now presenting pleiotropic effects on therapy and drug delivery. In this study, a profiling on the physiological functions, therapeutic significances, clinical/preclinical performances, and biomedical and drug delivery applications of selenium in different modalities was carried out. Major interests focused on selenium-based nanomedicines in confronting various diseases pertaining to selenium or not, especially in antitumor and antidiabetes. Furthermore, the article exclusively discusses selenium nanoparticles featured by ameliorative functions with emphasis on their applications in medical practice and drug delivery. The state-of-the-art in medical discovery as well as research and development on selenium and nano-selenium is discussed in this review.

Nano-selenium and its nanomedicine applications: a critical review

Traditional supplements of selenium generally have a low degree of absorption and increased toxicity. Therefore, it is imperative to develop innovative systems as transporters of selenium compounds, which would raise the bioavailability of this element and allow its controlled release in the organism. Nanoscale selenium has attracted a great interest as a food additive especially in individuals with selenium deficiency, but also as a therapeutic agent without significant side effects in medicine. This review is focused on the incorporation of nanotechnological applications, in particular exploring the possibilities of a more effective way of administration, especially in selenium-deficient organisms. In addition, this review summarizes the survey of knowledge on selenium nanoparticles, their biological effects in the organism, advantages, absorption mechanisms, and nanotechnological applications for peroral administration.

Combinatorial drug delivery strategy employing nano-curcumin and nano-MiADMSA for the treatment of arsenic intoxication in mouse

Chelation therapy is the mainstream treatment for heavy metal poisoning. Apart from this, therapy using antioxidant/herbal extracts are the other strategies now commonly being tried for the treatment. We have previously reported individual beneficial efficacy of nanoparticle mediated administration of an antioxidant like 'curcumin' and an arsenic chelator 'monoisoamyl 2,3-dimercaptosuccinic acid (MiADMSA)' for the treatment of arsenic toxicity compared to bulk drugs. The present paper investigates our hypothesis that a combination drug delivery therapy employing two nanosystems, a chelator and a strong antioxidant, may produce more pronounced therapeutic effects compared to individual effects in the treatment of arsenic toxicity. An in-vivo study was conducted wherein arsenic as sodium arsenite (100 ppm) was administered in drinking water for 5 months to Swiss albino mice. This was followed by a treatment protocol comprising of curcumin encapsulated chitosan nanoparticles (nano-curcumin, 15 mg/kg, orally for 1 month) either alone or in combination with MiADMSA encapsulated polymeric nanoparticles (nano-MiADMSA, 50 mg/kg for last 5 days) to evaluate the therapeutic potential of the combination treatment. Our results demonstrated that co-treatment with nano-curcumin and nano-MiADMSA provided beneficial effects in a synergistic way on the adverse changes in oxidative stress parameters and metal status induced by arsenic.

Stability of biogenic metal(loid) nanomaterials related to the colloidal stabilization theory of chemical nanostructures

In the last 15 years, the exploitation of biological systems (i.e. plants, bacteria, mycelial fungi, yeasts, and algae) to produce metal(loid) (Me)-based nanomaterials has been evaluated as eco-friendly and a cost-effective alternative to the chemical synthesis processes. Although the biological mechanisms of biogenic Me-nanomaterial (Bio-Me-nanomaterials) production are not yet completely elucidated, a key advantage of such bio-nanostructures over those chemically synthesized is related to their natural thermodynamic stability, with several studies ascribed to the presence of an organic layer surrounding these Bio-Me-nanostructures. Different macromolecules (e.g. proteins, peptides, lipids, DNA, and polysaccharides) or secondary metabolites (e.g. flavonoids, terpenoids, glycosides, organic acids, and alkaloids) naturally produced by organisms have been indicated as main contributors to the stabilization of Bio-Me-nanostructures. Nevertheless, the chemical-physical mechanisms behind the ability of these molecules in providing stability to Bio-Me-nanomaterials are unknown. In this context, transposing the stabilization theory of chemically synthesized Me-nanomaterials (Ch-Me-nanomaterials) to biogenic materials can be used towards a better comprehension of macromolecules and secondary metabolites role as stabilizing agents of Bio-Me-nanomaterials. According to this theory, nanomaterials are generally featured by high thermodynamic instability in suspension, due to their high surface area and surface energy. This feature leads to the necessity to stabilize chemical nanostructures, even during or directly after their synthesis, through the development of (i) electrostatic, (ii) steric, or (iii) electrosteric interactions occurring between molecules and nanomaterials in suspension. Based on these three mechanisms, this review is focused on parallels between the stabilization of biogenic or chemical nanomaterials, suggesting which chemical-physical mechanisms may be involved in the natural stability of Bio-Me-nanomaterials. As a result, macromolecules such as DNA, polyphosphates and proteins may electrostatically interact with Bio-Me-nanomaterials in suspension through their charged moieties, showing the same properties of counterions in Ch-Me-nanostructure suspensions. Since several biomolecules (e.g. neutral lipids, nonionic biosurfactants, polysaccharides, and secondary metabolites) produced by metal(loid)-grown organisms can develop similar steric hindrance as compared to nonionic amphiphilic surfactants and block co-polymers generally used to sterically stabilize Ch-Me-nanomaterials. These biomolecules, most likely, are involved in the development of steric stabilization, because of their bulky structures. Finally, charged lipids and polysaccharides, ionic biosurfactants or proteins with amphiphilic properties can exert a dual effect (i.e. electrostatic and steric repulsion interactions) in the contest of Bio-Me-nanomaterials, leading to the high degree of stability observed.

Nutritional management can assist a significant role in alleviation of arsenicosis

Consumption of arsenic contaminated water causes serious skin disease and cancer in a significant number of exposed people. Chelating agents, consider an expensive therapy, are employed in the treatment of arsenic intoxication. There are reports which suggest that the poorest suffer the most from arsenicosis. This may be due to improper diet intake, consist of low protein and micronutrients which increase the vulnerability to arsenic-related disorders. Several human studies demonstrated the associations between malnourishment and the development of arsenic-caused skin lesions, skin cancer and cardiovascular effects. Thus, there is an urgent need of implementation of mitigation strategies for improving the health of exposed populations. Nutrition enhances the detoxification process so food rich in vitamins, protein, antioxidants help in its detoxification process. Methylation is the detoxification process which takes place via S-adenosylmethionine (SAM). It is a methyl group donor and it derived its methyl group from diet. Nutritional intervention thus may appear as a practical and inexpensive approach. Nutrition provides protection from toxic effect of arsenic by two ways (i) methylation of As (ii) antioxidants which provides protection against free radical species. The governments and NGOs may run awareness programmes in arsenic affected area regarding prevention and alternate therapy which can decrease the susceptibility of the exposed population. They could also help in distributing cheaper, high protein diets particularly to the masses who cannot afford such foods. Thus, to prevent arsenicosis alternate therapy and proper nutrition could be the important strategy for alleviating its toxic effects. This mini review provides an insight on the importance of nutrition in preventing adverse effect cause by arsenic to suffer population.

Supplementation of Micronutrient Selenium in Metabolic Diseases: Its Role as an Antioxidant

Selenium is an essential mineral naturally found in soil, water, and some of the food. As an antioxidant, it is one of the necessary trace elements in human body and has been suggested as a dietary supplement for health benefit. Although the human body only needs a trace amount of selenium every day, plenty of recent studies have revealed that selenium is indispensable for maintaining normal functions of metabolism. In this study, we reviewed the antioxidant role of nutritional supplementation of selenium in the management of major chronic metabolic disorders, including hyperlipidaemia, hyperglycaemia, and hyperphenylalaninemia. Clinical significance of selenium deficiency in chronic metabolic diseases was elaborated, while clinical and experimental observations of dietary supplementation of selenium in treating chronic metabolic diseases, such as diabetes, arteriosclerosis, and phenylketonuria, were summarized. Toxicity and recommended dose of selenium were discussed. The mechanism of action was also proposed via inspecting the interaction of molecular networks and predicting target protein such as xanthine dehydrogenase in various diseases. Future direction in studying the role of selenium in metabolic disorders was also highlighted. In conclusion, highlighting the beneficial role of selenium in this review would advance our knowledge of the dietary management of chronic metabolic diseases.

Assessment of toxicity of selenium and cadmium selenium quantum dots: A review

This paper reviews the current understanding of the toxicity of selenium (Se) to terrestrial mammalian and aquatic organisms. Adverse biological effects occur in the case of Se deficiencies, associated with this element having essential biological functions and a narrow window between essentiality and toxicity. Several inorganic species of Se (-2, 0, +4, and +6) and organic species (monomethylated and dimethylated) have been reported in aquatic systems. The toxicity of Se in any given sample depends not only on its speciation and concentration, but also on the concomitant presence of other compounds that may have synergistic or antagonistic effects, affecting the target organism as well, usually spanning 2 or 3 orders of magnitude for inorganic Se species. In aquatic ecosystems, indirect toxic effects, linked to the trophic transfer of excess Se, are usually of much more concern than direct Se toxicity. Studies on the toxicity of selenium nanoparticles indicate the greater toxicity of chemically generated selenium nanoparticles relative to selenium oxyanions for fish and fish embryos while oxyanions of selenium have been found to be more highly toxic to rats as compared to nano-Se. Studies on polymer coated Cd/Se quantum dots suggest significant differences in toxicity of weathered vs. non-weathered QD's as well as a significant role for cadmium with respect to toxicity.

Selenium nanoparticles with low-level ionizing radiation exposure ameliorate nicotine-induced inflammatory impairment in rat kidney

Occupational exposure to low-level ionizing radiation (<1 Gy) was shown to enhance cell protection via attenuating an established inflammatory process. Nicotine, a major toxic component of cigarette smoke, is responsible for smoking-mediated renal dysfunction. The present study was therefore aimed to investigate the protective impact of ginger Zingiber officinale selenium nanoparticles (SeNPs) with whole-body low-dose gamma radiation (γ-R) against nicotine-induced nephrotoxicity in male albino rats. Nicotine intoxication was induced with 0.5 mg/kg BW. Rats received 0.1 mg SeNPs/kg BW by gastric gavage concomitant with 0.5 Gy γ-R over 4 weeks. Characterization studies showed the formation of spherical SeNPs with a size ranged from 10 to 30 nm in diameter with a thin film encapsulating the nanoballs. Our data revealed that nicotine induced renal dysfunction manifested by significant abnormal levels of kidney function markers (creatinine, urea, sodium and potassium) accompanied by increased levels of malondialdehyde along with a reduction in glutathione level, glutathione peroxidase, and glutathione S-transferase activities. It is worthy to note that nicotine toxicity induced significant increments in serum inflammatory markers: tumor necrosis factor-α and vascular cell adhesion protein 1. Western blotting showed marked significant elevation in caspase-3 activities against nicotine. The mRNA gene expression of inducible cyclooxygenase-2 gene was highly increased with nicotine intoxication while that of cyclooxygenase-1 did not show any changes. Interestingly, our data demonstrated that SeNPs in synergistic interaction with γ-R are efficacious control against nicotine-induced nephrotoxicity via anti-oxidant-mediated anti-inflammatory activities. Thus, it is tempting to recommend dietary approaches with ginger SeNPs for smokers at workplaces exposed occupationally and regularly to low-level ionizing radiation.

Selenium nanoparticles: potential in cancer gene and drug delivery

In recent decades, colloidal selenium nanoparticles have emerged as exceptional selenium species with reported chemopreventative and therapeutic properties. This has sparked widespread interest in their use as a carrier of therapeutic agents with results displaying synergistic effects of selenium with its therapeutic cargo and improved anticancer activity. Functionalization remains a critical step in selenium nanoparticles' development for application in gene or drug delivery. In this review, we highlight recent developments in the synthesis and functionalization strategies of selenium nanoparticles used in cancer drug and gene delivery systems. We also provide an update of recent preclinical studies utilizing selenium nanoparticles in cancer therapeutics.

Nano drug delivery systems: a new paradigm for treating metal toxicity

INTRODUCTION

The standard medical treatment for metal toxicity is chelation therapy. Chelating agents work by forming less toxic complexes with the toxic metal ions which are readily excreted from the body. These compounds, based on their hydrophilic/lipophilic property, can either remove toxic metal ions from extracellular sites or can penetrate the intracellular compartments to facilitate the removal of toxic metal ions. However, there are various disadvantages associated with this kind of therapy, notably, selectivity. Other problems and challenges are that the therapy regime is expensive, time consuming and has poor patient compliance. Two chelating agents, dimercaptosuccinic acid (DMSA) and dimercaptopropionicsulfonate (DMPS) have gained increased acceptance among clinicians, undoubtedly improving the management of metal intoxications.

AREAS COVERED

The present review provides an insight into the conventional chelating agents, new chelators under development, and the new opportunities presented by the use of nanotherapy for the treatment of metal poisoning cases.

EXPERT OPINION

Today's research should not only focus towards development of alternate chelators but also targeted therapy such as the nanotherapy.

Anticancer activity of biostabilized selenium nanorods synthesized by Streptomyces bikiniensis strain Ess_amA-1

Selenium is an important component of human diet and a number of studies have declared its chemopreventive and therapeutic properties against cancer. However, very limited studies have been conducted about the properties of selenium nanostructured materials in comparison to other well-studied selenospecies. Here, we have shown that the anticancer property of biostabilized selenium nanorods (SeNrs) synthesized by applying a novel strain Ess_amA-1 of Streptomyces bikiniensis. The strain was grown aerobically with selenium dioxide and produced stable SeNrs with average particle size of 17 nm. The optical, structural, morphological, elemental, and functional characterizations of the SeNrs were carried out using techniques such as UV-vis spectrophotometry, transmission electron microscopy, energy dispersive X-ray spectrometry, and Fourier transform infrared spectrophotometry, respectively. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay revealed that the biosynthesized SeNrs induces cell death of Hep-G2 and MCF-7 human cancer cells. The lethal dose (LD50%) of SeNrs on Hep-G2 and MCF-7 cells was recorded at 75.96 μg/mL and 61.86 μg/mL, respectively. It can be concluded that S. bikiniensis strain Ess_amA-1 could be used as renewable bioresources of biosynthesis of anticancer SeNrs. A hypothetical mechanism for anticancer activity of SeNrs is also proposed.

Carboxylic group-induced synthesis and characterization of selenium nanoparticles and its anti-tumor potential on Dalton's lymphoma cells

Carboxylic group-induced synthesis of selenium nanoparticles (SeNPs) was achieved using sodium selenosulphate as a precursor. The particles were stabilized and capped with 0.01% polyvinyl alcohol under ambient conditions. This is a simple and easy method of producing SeNPs in a size range from 35 to 105 nm. The synthesized SeNPs were purified by centrifugation at 11,500 × g for 20 min and characterized by UV-visible spectroscopy, FTIR spectroscopy, XRD, DSC and TEM. It was observed that the synthesized SeNPs showed differences in their absorption spectra, phase composition and crystal structure, thermodynamic behaviour, size and shape. Further, to confirm anti-tumour potential of the synthesized SeNPs induced by the carboxylic group of acetic acid, pyruvic acid and benzoic acid, cell viability assay, nuclear morphology testing and DNA fragmentation assay were carried out using Dalton's lymphoma (DL) cells. DL cells treated with the SeNPs showed reduced cell viability, altered nuclear morphology, typical apoptotic DNA ladder and apoptosis. Therefore, these SeNPs may have therapeutic relevance to treat this type of cancer.

Plants and microbes assisted selenium nanoparticles: characterization and application

Selenium is an essential trace element and is an essential component of many enzymes without which they become inactive. The Se nanoparticles of varying shape and size may be synthesized from Se salts especially selenite and selenates in presence of reducing agents such as proteins, phenols, alcohols and amines. These biomolecules can be used to reduce Se salts in vitro but the byproducts released in the environment may be hazardous to flora and fauna. In this review, therefore, we analysed in depth, the biogenic synthesis of Se nanoparticles, their characterization and transformation into t- Se, m-Se, Se-nanoballs, Se-nanowires and Se-hollow spheres in an innocuous way preventing the environment from pollution. Their shape, size, FTIR, UV-vis, Raman spectra, SEM, TEM images and XRD pattern have been analysed. The weak forces involved in aggregation and transformation of one nano structure into the other have been carefully resolved.

Plants and microbes assisted selenium nanoparticles: characterization and application

Selenium is an essential trace element and is an essential component of many enzymes without which they become inactive. The Se nanoparticles of varying shape and size may be synthesized from Se salts especially selenite and selenates in presence of reducing agents such as proteins, phenols, alcohols and amines. These biomolecules can be used to reduce Se salts in vitro but the byproducts released in the environment may be hazardous to flora and fauna. In this review, therefore, we analysed in depth, the biogenic synthesis of Se nanoparticles, their characterization and transformation into t- Se, m-Se, Se-nanoballs, Se-nanowires and Se-hollow spheres in an innocuous way preventing the environment from pollution. Their shape, size, FTIR, UV-vis, Raman spectra, SEM, TEM images and XRD pattern have been analysed. The weak forces involved in aggregation and transformation of one nano structure into the other have been carefully resolved.