Silver nanoparticles (AgNPs) as a metal nano-therapy: possible mechanisms of antiviral action against COVID-19

Environmental factors modify silver nanoparticles ecotoxicity in Chydorus eurynotus (Cladocera)

Silver nanoparticles (AgNPs) are among the most produced nanomaterials in the world and are incorporated into several products due to their biocide and physicochemical properties. Since freshwater bodies are AgNPs main final sink, several consequences for biota are expected to occur. With the hypothesis that AgNPs can interact with environmental factors, we analyzed their ecotoxicity in combination with humic acids and algae. In addition to the specific AgNPs behavior in the media, we analyzed the mortality, growth, and phototactic behavior of Chydorus eurynotus (Cladocera) as response variables. While algae promoted Ag+ release, humic acids reduced it by adsorption, and their combination resulted in an intermediated Ag+ release. AgNPs affected C. eurynotus survival and growth, but algae and humic acids reduced AgNPs lethality, especially when combined. The humic acids mitigated AgNP effects in C. eurynotus growth, and both factors improved its phototactic behavior. It is essential to deepen the study of the isolated and combined influences of environmental factors on the ecotoxicity of nanoparticles to achieve accurate predictions under realistic exposure scenarios.

Medical Applications of Silver and Gold Nanoparticles and Core-Shell Nanostructures Based on Silver or Gold Core: Recent Progress and Innovations

Nanoparticles (NPs) of noble metals such as silver (Ag NPs) or gold (Au NPs) draw the attention of scientists looking for new compounds to use in medical applications. Scientists have used metal NPs because of their easy preparation, biocompatibility, ability to influence the shape and size or modification, and surface functionalization. However, to fully use their capabilities, both the benefits and their potential threats should be considered. One possibility to reduce the potential threat and thus prevent the extinction of their properties resulting from the agglomeration, they are covered with a neutral material, thus obtaining core-shell nanostructures that can be further modified and functionalized depending on the subsequent application. In this review, we focus on discussing the properties and applications of Ag NPs and Au NPs in the medical field such as the treatment of various diseases, drug carriers, diagnostics, and many others. In addition, the following review also discusses the use and potential applications of Ag@SiO2 and Au@SiO2 core-shell nanostructures, which can be used in cancer therapy and diagnosis, treatment of infections, or tissue engineering.

Plant-mediated green synthesis of gold nanoparticles using an aqueous extract of Passiflora ligularis, optimization, characterizations, and their neuroprotective effect on propionic acid-induced autism in Wistar rats

The current study was conducted to examine an innovative method for synthesizing gold nanoparticles (AuNPs) from an aqueous sweet granadilla (Passiflora ligularis Juss) P. ligularis. Furthermore, the synthesized AuNPs were used to explore their potential neuroprotective impact against propionic acid (PPA)-induced autism. A sweet granadilla extract was used to achieve the synthesis of AuNPs. The structural and dimensional dispersion of AuNPs were confirmed by different techniques, including UV-Vis spectrophotometer (UV-Vis), X-ray Diffraction (XRD) Pattern, Energy Dispersive X-ray (EDX), Zeta potential, and High-Resolution Transmission Electron Microscopy (HRTEM) analysis. The AuNPs mediated by P. ligularis adopt a spherical shape morphology and the particle size was distributed in the range of 8.43-13 nm without aggregation. Moreover, in vivo, the anti-autistic effects of AuNPs administration were higher than those of P. ligularis extract per second. In addition, the reduced anxiety and neurobehavioral deficits of AuNPs were observed in autistic rats which halted the brain oxidative stress, reduced inflammatory cytokines, ameliorated neurotransmitters, and neurochemical release, and suppressed apoptotic genes (p < 0.05). The alleviated antiapoptotic gene expression and histopathological analysis confirmed that the treatment of AuNPs showed significant neural pathways that aid in reducing tissue damage and necrosis. The results emphasize that the biomedical activity was increased by using the green source synthesis P. ligularis -AuNPs. Additionally, the formulation of AuNPs demonstrates strong neuroprotective effects against PPA-induced autism that were arbitrated by a range of different mechanisms, such as anti-inflammatory, antioxidant, neuromodulator, and antiapoptotic effects.

Adverse Effect of Metallic Gold and Silver Nanoparticles on Xenopus laevis Embryogenesis

Exposure to metal nanoparticles is potentially harmful, particularly when occurring during embryogenesis. In this study, we tested the effects of commercial AuNPs and AgNPs, widely used in many fields for their features, on the early development of Xenopus laevis, an anuran amphibian key model species in toxicity testing. Through the Frog Embryo Teratogenesis Assay-Xenopus test (FETAX), we ascertained that both nanoparticles did not influence the survival rate but induced morphological anomalies like modifications of head and branchial arch cartilages, depigmentation of the dorsal area, damage to the intestinal brush border, and heart rate alteration. The expression of genes involved in the early pathways of embryo development was also modified. This study suggests that both types of nanoparticles are toxic though nonlethal, thus indicating that their use requires attention and further study to better clarify their activity in animals and, more importantly, in humans.

A perception into binary and ternary copper (II) complexes: synthesis, characterization, DFT modeling, antimicrobial activity, protein binding screen, and amino acid interaction

Ensuring healthy lives and promoting well-being for all at all ages is the third goal of the sustainable development plan, so it was necessary to identify the most important problems that threaten health in our world. The World Health Organization declared that antibiotic resistance is one of the uppermost global public health threats facing humanity and searching for new antibiotics is slow. This problem can be approached by improving available drugs to combat various bacterial threats. To circumvent bacterial resistance, three copper(II) complexes based on the pefloxacin drug were prepared and characterized using analytical, spectroscopic, and thermal techniques. The resulting data suggested the formation of one octahedral binary and two distorted square pyramidal ternary complexes. Fluorescence spectra results revealed the formation of a turn-on fluorophore for amino acid detection. Computational calculations investigated quantum and reactivity parameters. Molecular electrostatic potential profiles and noncovalent bond interaction-reduced density gradient analysis indicated the active sites on the complex surface. The complexes were subjected to six microbial species, where the octahedral binary complex provoked its antimicrobial potency in comparison with ternary complexes. The enhanced antimicrobial activity against gram-negative bacterium E-coli compared to gentamicin was exhibited by the three complexes. Docking simulation was performed based on the crystal structure of E. coli and S. pneumoniae receptors using 5I2D and 6O15 codes. The binary complex exhibited a potent fitness score with 5I2D (TBE = - 107 kcal/mol) while ternary complexes displayed the highest docked score of fitness with 6O15.

Advancements of Nanotechnology and Nanomaterials in Environmental and Human Protection for Combatting the COVID-19 During and Post-pandemic Era: A Comprehensive Scientific Review

In December 2019, an outbreak of unknown pneumonia emerged in Wuhan City, Hubei Province, China. It was later identified as the SARS-CoV-2 virus and has since infected over 9 million people in more than 213 countries worldwide. Massive papers on the topic of SARS-CoV-2 that have already been published are necessary to be analyzed and discussed. This paper used the combination of systematic literature network analysis and content analysis to develop a comprehensive discussion related to the use of nanotechnology and materials in environmental and human protection. Its is shown that various efforts have been made to control the transmission of this pandemic. Nanotechnology plays a crucial role in modern vaccine design, as nanomaterials are essential tools for antigen delivery, adjuvants, and mimics of viral structures. In addition, nanomaterials and nanotechnology also reported a crucial role in environmental protection for defence and treating the pandemic. To eradicate pandemics now and in the future, successful treatments must enable rapid discovery, scalable manufacturing, and global distribution. In this review, we discuss the current approaches to COVID-19 development and highlight the critical role of nanotechnology and nanomaterials in combating the virus in the human body and the environment.

Nanofabrication synthesis and its role in antibacterial, anti-inflammatory, and anticoagulant activities of AgNPs synthesized by Mangifera indica bark extract

The bio-based nanoparticles synthesis and assessment of their potential biomedical applications related research is rapidly emerging. The ability of an aqueous ethanolic bark extract of Mangifera indica to synthesize silver nanoparticles (AgNPs) as well as its antibacterial, anti-inflammatory, and anticancer activities were investigated in this study. Interestingly, the bark extract effectively synthesized the AgNPs, including an absorbance peak at 412 nm and sizes ranging from 56 to 89 nm. The Fourier Transform Infrared spectroscopy (FTIR) analysis confirmed that the presence of most essential functional groups belongs to the most bioactive compounds. Synthesized AgNPs showed fine antibacterial activity against the Urinary Tract Infection (UTI) causing bacterial pathogens such as Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, Proteus mirabilis, and Staphylococcus saprophyticus at 50 μg mL^-1 concentrations. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of AgNPs against these pathogens were found as 12.5 ± 0.8 & 13 ± 0.6, 13.6 ± 0.5 & 14 ± 0.7, 11.5 ± 0.3 & 11.5 ± 0.4, 13 ± 0.8 & 13 ± 0.7, and 11.8 ± 0.4 & 12 ± 0.8 μg mL^-1 respectively. Interestingly, this AgNPs also possesses outstanding anti-inflammatory and anticancer activities as studied against the egg albumin denaturation (85%) inhibition and MCF 7 (Michigan Cancer Foundation-7: breast cancer cells) cell line (cytotoxicity: 80.1%) at 50 μg mL^-1 concentration. Similarly at 50 μg mL^-1 concentration showed 75% of DPPH radical scavenging potential. These activities were dose dependent, and the findings suggest that the M. indica bark aqueous ethanolic extract synthesized AgNPs can be used as antibacterial, anti-inflammatory, and anticancer agents after in-vivo testing.

The Effect of Silver Nanoparticle Addition on Micropropagation of Apricot Cultivars (Prunus armeniaca L.) in Semisolid and Liquid Media

Silver nanoparticles (AgNPs) are novel compounds used as antimicrobial and antiviral agents. In addition, AgNPs have been used to improve the growth of different plants, as well as the in vitro multiplication of plant material. In this work the effect of AgNPs on in vitro growth of 'Canino' and 'Mirlo Rojo' cultivars, as well as the leaf ion composition, are studied. Different concentrations of AgNPs (0, 25, 50, 75 and 100 mg L^-1) were added to two culture systems: semisolid medium with agar (SSM) in jars and liquid medium in temporary immersion system (TIS). Proliferation (number of shoots), shoot length, productivity (number of shoot × average length), leaf surface, fresh and dry weight were measured. Additionally, the silver and other ion accumulation in the leaves were evaluated by inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis. The productivity of 'Canino' and 'Mirlo Rojo' decreased when increasing the concentration of AgNPs in the semisolid medium. However, the use of AgNPs in the TIS improved the proliferation and productivity of 'Canino' and Mirlo Rojo', increasing biomass production, and the concentration of nutrients in the plants, although these effects are genotype-dependent. TISs are the best system for introducing silver into shoots, the optimum concentration being 50 mg L^-1 for 'Canino' and 75 mg L^-1 for 'Mirlo Rojo'. Principal component analysis, considering all the analyzed ions along the treatments, separates samples in two clear groups related to the culture system used. The use of bioreactors with a liquid medium has improved the productivity of 'Canino' and 'Mirlo Rojo' in the proliferation stage, avoiding hyperhydration and other disorders. The amount of metallic silver that penetrates apricot plant tissues depends on the culture system, cultivar and concentration of AgNPs added to the culture medium. Silver ion accumulation measured in the shoots grown in the TIS was higher than in shoots micropropagated in a semisolid medium, where it is barely detectable. Furthermore, AgNPs had a beneficial effect on plants grown in TIS. However, AgNPs had a detrimental effect when added to a semisolid medium.

Therapeutic and diagnostic applications of nanoparticles in the management of COVID-19: a comprehensive overview

In December 2019, Coronavirus Disease 2019 (COVID-19) was reported in Wuhan, China. Comprehensive strategies for quick identification, prevention, control, and remedy of COVID-19 have been implemented until today. Advances in various nanoparticle-based technologies, including organic and inorganic nanoparticles, have created new perspectives in this field. These materials were extensively used to control COVID-19 because of their specific attribution to preparing antiviral face masks, various safety sensors, etc. In this review, the most current nanoparticle-based technologies, applications, and achievements against the coronavirus were summarized and highlighted. This paper also offers nanoparticle preventive, diagnostic, and treatment options to combat this pandemic.

Green Synthesis of Trimetallic Nanocomposite (Ru/Ag/Pd)-Np and Its In Vitro Antimicrobial and Anticancer Activities

In this study, we used the aqueous extract of garlic tunicate leaf to reduce a mixture of equal amounts of ruthenium chloride, silver nitrate, and palladium acetate for the biosynthesis of ruthenium/silver/palladium trimetallic nanocomposite (Ru/Ag/Pd)-Np. Some physicochemical tools were used for nanocomposite characterization, including Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), UV-Vis spectroscopy (UV-Vis), scanning electron microscope (SEM), and transmittance electron microscope (TEM). XRD revealed that the crystal size of the nanocomposite is 15.67 nm. The TEM images showed that the particle size ranged 50–90 nm. The antimicrobial efficacy of the nanocomposite was examined against Aspergillus flavus, Aspergillus niger, Candida albicans, Candida glabrata, Escherichia coli, and Bacillus cereus. The results showed a potent antimicrobial activity toward all tested microorganisms. (Ru/Ag/Pd)-Np showed antiproliferative activity against Caco-2, HepG2, and K562 cell lines. The antiproliferative potential of (Ru/Ag/Pd)-Np was significantly improved following UV irradiation.

Single-step green synthesis of gold conjugated polyphenol nanoparticle using extracts of Saudi's myrrh: Their characterization, molecular docking and essential biological applications

The progress in the innovative nanocrystal synthesis process by using environmentally benign and low-priced nontoxic chemicals, solvents, and renewable sources remains a challenging task for researchers worldwide. The majority of the existing synthesis techniques engage in the potentially dangerous, for either human health or the environment. Current investigation has been centered on green synthesis processes to create novel nanomaterials, which are eco-friendly as well as safer for sustainable marketable feasibility. The current work provides the green synthesis method for gold nanoparticle (GNPs) synthesis using Commiphora myrrh (C.myrrh) extract. This simple method includes 6 ml of HAuCl4·3H2O treated with 4 ml C.myrrh extract having pH 4.5 after 80 min at 25 °C temperature. In this novel method, green synthesized GNPs characterized by UV-Vis, X_ray diffraction spectroscopy (XRD), zeta potential, fourier transform infrared (FT_IR), high_resolution transmission electron microscopy (HR_TEM), energy dispersive X_ray spectroscopy (EDXA), and dynamic light scattering (DLS). During the development successful antioxidant assay, the DPPH assay was applied. The cell toxicity of green synthesized GNPs was evaluated following an MTT assay against HCT-116 (colon cancer) and MCF-7 (breast cancer). Besides molecular docking in the δ-elemene for inhibitor to VEGFR-2 domain revealed more negative docking score (-3.976) which is an excellent binding affinity to the C.myrrh@GNP. The synthesized GNPs showed antidiabetic, antibiotic, and antibacterial properties and anti_inflammatory inhibition against inhibiting COX-1, and COX-2 enzymes. In addition, molecular docking by Lindestrene (-3.806) and Furanoeudesma-1,3-dien (-3.912) against COX1 and COX2 respectively showed strong binding affinity. The molecular docking study evidenced the anti-inflammatory and cell toxicity study.

Development of Metal Complexes for Treatment of Coronaviruses

Coronavirus disease (SARS-CoV-2) is a global epidemic. This pandemic, which has been linked to high rates of death, has forced some countries throughout the world to implement complete lockdowns in order to contain the spread of infection. Because of the advent of new coronavirus variants, it is critical to find effective treatments and vaccines to prevent the virus’s rapid spread over the world. In this regard, metal complexes have attained immense interest as antibody modifiers and antiviral therapies, and they have a lot of promise towards SARS-CoV-2 and their suggested mechanisms of action are discussed, i.e., a new series of metal complexes’ medicinal vital role in treatment of specific proteins or SARS-CoV-2 are described. The structures of the obtained metal complexes were fully elucidated by different analytical and spectroscopic techniques also. Molecular docking and pharmacophore studies presented that most of complexes studied influenced good binding affinity to the main protease SARS-CoV-2, which also was attained as from the RCSB pdb (Protein Data Bank) data PDB ID: 6 W41, to expect the action of metal complexes in contradiction of COVID-19. Experimental research is required to determine the pharmacokinetics of most of the complexes analyzed for the treatment of SARS-CoV-2-related disease. Finally, the toxicity of a metal-containing inorganic complex will thus be discussed by its capability to transfer metals which may bind with targeted site.