Rapid biosynthesis of irregular shaped gold nanoparticles from macerated aqueous extracellular dried clove buds (Syzygium aromaticum) solution

Harnessing nature's potential: Alpinia galanga methanolic extract mediated green synthesis of silver nanoparticle, characterization and evaluation of anti-neoplastic activity

With the advent of nanotechnology, the treatment of cancer is changing from a conventional to a nanoparticle-based approach. Thus, developing nanoparticles to treat cancer is an area of immense importance. We prepared silver nanoparticles (AgNPs) from methanolic extract of Alpinia galanga rhizome and characterized them by UV-Vis spectrophotometry, Fourier transform Infrared (FTIR) spectroscopy, Zetasizer, and Transmission electron Microscopy (TEM). UV-Vis spectrophotometry absorption spectrum showed surface plasmon between 400 and 480 nm. FTIR spectrum analysis implies that various phytochemicals/secondary metabolites are involved in the reduction, caping, and stabilization of AgNPs. The Zetasier result suggests that the particles formed are small in size with a low polydispersity index (PDI), suggesting a narrow range of particle distribution. The TEM image suggests that the particles formed are mostly of spherical morphology with nearly 20-25 nm. Further, the selected area electron diffraction (SAED) image showed five electron diffraction rings, suggesting the polycrystalline nature of the particles. The nanoparticles showed high anticancer efficacy against cervical cancer (SiHa) cell lines. The nanostructures showed dose-dependent inhibition with 40% killing observed at 6.25 µg/mL dose. The study showed an eco-friendly and cost-effective approach to the synthesis of AgNPs and provided insight into the development of antioxidant and anticancer agents.

Padina boergesenii mediated synthesis of Se-ZnO bimetallic nanoparticles for effective anticancer activity

Introduction

Evaluating the anticancer property of Padina boergesenii mediated bimetallic nanoparticles.

Methods

The present study focuses on synthesizing Se-ZnO bimetallic nanoparticles from an aqueous algal extract of brown algae Padina boergesenii.Synthesized Se-ZnO NPs were characterized by UV, FTIR, SEM-EDS and HRTEM for confirmation along with the anticancer activity by MTT assay.

Results

The UV gave an absorbance peak at 342 and 370 nm, and the FTIR showed functional groups involved in synthesizing Se-ZnO NPs. The TEM micrographs indicated the crystalline nature and confirmed the size of the Se-ZnO NPs to be at an average size of 26.14 nm. Anticancer efficacy against the MCF-7 breast and HepG2 (hepatoblastoma) cell lines were also demonstrated, attaining an IC50 value of 67.9 µg and 74.9 µg/ml respectively, which caused 50% cell death.

Discussion

This work aims to highlight an effective method for delivering bioactive compounds extracted from brown algae and emphasize its future therapeutic prospects. The potential of Selenium-Zinc oxide nanoparticles is of great interest due to the biocompatibility and low toxicity aspects of selenium combined with the cost-effectiveness and sustainability of zinc metal. The presence of bioactive compounds contributed to the stability of the nanoparticles and acted as capping properties.

Natural compounds as lactate dehydrogenase inhibitors: potential therapeutics for lactate dehydrogenase inhibitors-related diseases

Lactate dehydrogenase (LDH) is a crucial enzyme involved in energy metabolism and present in various cells throughout the body. Its diverse physiological functions encompass glycolysis, and its abnormal activity is associated with numerous diseases. Targeting LDH has emerged as a vital approach in drug discovery, leading to the identification of LDH inhibitors among natural compounds, such as polyphenols, alkaloids, and terpenoids. These compounds demonstrate therapeutic potential against LDH-related diseases, including anti-cancer effects. However, challenges concerning limited bioavailability, poor solubility, and potential toxicity must be addressed. Combining natural compounds with LDH inhibitors has led to promising outcomes in preclinical studies. This review highlights the promise of natural compounds as LDH inhibitors for treating cancer, cardiovascular, and neurodegenerative diseases.

Preferential role of distinct phytochemicals in biosynthesis and antibacterial activity of silver nanoparticles

Biosynthesis of silver nanoparticles (AgNPs) by plant extracts and its antibacterial utilization has attracted great attention due to the spontaneous reducing and capping capacities of phytochemicals. However, the preferential role and mechanisms of the functional phytochemicals from different plants on AgNPs synthesis, and its catalytic and antibacterial performance remain largely unknown. This study used three widespread arbor species, including Eriobotrya japonica (EJ), Cupressus funebris (CF) and Populus (PL), as the precursors and their leaf extracts as reducing and stabilizing agents for the biosynthesis of AgNPs. A total of 18 phytochemicals in leaf extracts were identified by ultra-high liquid-phase mass spectrometer. For EJ extracts, most kinds of flavonoids participated in the generation of AgNPs by a reduced content of 5∼10%, while for CF extracts, about 15∼40% of the polyphenols were consumed to reduce Ag+ to Ag0. Notably, the more stable and homogeneous spherical AgNPs with smaller size (≈38 nm) and high catalytic capacity on Methylene blue were obtained from EJ extracts rather than CF extracts, and no AgNPs were synthesized from PL extracts, indicating that flavonoids are superior than polyphenols to act as reducer and stabilizer in AgNPs biosynthesis. The antibacterial activities against Gram-positive (Staphylococcus aureus and Bacillus mycoides) and Gram-negative bacteria (Pseudomonas putida and Escherichia coli) were higher in EJ-AgNPs than that in CF-AgNPs, which confirmed the synergistic antibacterial effects of flavonoids combined with AgNPs in EJ-AgNPs. This study provides a significant reference on the biosynthesis of AgNPs with efficient antibacterial utilization underlying effect of abundant flavonoids in plant extracts.

A State-of-the-Art Systemic Review on Selenium Nanoparticles: Mechanisms and Factors Influencing Biogenesis and Its Potential Applications

Selenium is a trace element required for the active function of numerous enzymes and various physiological processes. In recent years, selenium nanoparticles draw the attention of scientists and researchers because of its multifaceted uses. The process involved in chemically synthesized SeNPs has been found to be hazardous in nature, which has paved the way for safe and ecofriendly SeNPs to be developed in order to achieve sustainability. In comparison to chemical synthesis, SeNPs can be synthesized more safely and with greater flexibility utilizing bacteria, fungi, and plants. This review focused on the synthesis of SeNPs utilizing bacteria, fungi, and plants; the mechanisms involved in SeNP synthesis; and the effect of various abiotic factors on SeNP synthesis and morphological characteristics. This article discusses the synergies of SeNP synthesis via biological routes, which can help future researchers to synthesize SeNPs with more precision and employ them in desired fields.

Preparation of nanocomposite based on chitosan-PDCOEMA containing biosynthesized ZnO: Biological and thermal characterization

In this study, poly(2-(3,5-dichloroanilino)-2-oxoethyl 2-methylprop-2-enoate) (PDCOEMA), a new synthetic polymer based on methacrylate, was synthesized and characterized. The blend of PDCOEMA with chitosan (CS) was prepared by the hydrothermal method and the DSC technique confirmed its formation. It was observed that PDCOEMA increased the thermal stability and glass transition temperature (Tg) of CS. The Tg value of the PDCOEMA-CS blend was increased at about 7 °C with the highest ZnO NPs contribution rate. PDCOEMA-CS/ZnO nanocomposites were prepared by adding ZnO NPs produced by biosynthesis at different weight ratios to the PDCOEMA-CS blend by hydrothermal method. When the thermal stability of nanocomposites determined by TGA was examined, it was observed that it increased significantly compared to CS. While the initial decomposition temperature of CS was 270 °C, this value increased to 293 °C after blending with DCOEMA, and to 317 °C with the addition of 7 % ZnO NPs. Antimicrobial, anticancer, cytotoxic, antioxidant, and wound healing properties of PDCOEMA, CS, PDCOEMA-CS blend, and nanocomposites were determined. According to the obtained results, it was observed that nanocomposites containing 5 % and 7 % ZnO NPs showed good anticancer activity against A549 cells at a dose of 10 μg/mL. The results show that the produced nanocomposites can contribute to developing CS-based materials.

Antimicrobial evaluation of silver nanoparticles using extracts of Crescentia cujete L

New natural reducing agents with a lower negative impact on the environment and with a high antimicrobial potential are required for the process of obtaining silver nanoparticles through the chemical reduction method. The use of plant extracts can be a fast track in the formation of nanoparticles. In this case, organic compounds such as terpenes, flavonoids, enzymes, proteins, and cofactors present in plants act as reducing agents for nanomaterials. This research evaluated the antimicrobial property of silver nanoparticles from extracts of Crescentia cujete L. The presence of quercetin (flavonoid) was determined by high-performance liquid chromatography (HPLC); the production of silver nanoparticles (AgNPs) was established by green synthesis; the size and morphology of the nanomaterials were evaluated by scanning electron microscope (SEM). The antimicrobial capacity was studied by two analysis methods: modified culture medium and surface seeding. The presence of quercetin (26.55 mg L-1) in the crude extract of Crescentia cujete L., identified by HPLC, was evidenced. Nanoparticle formation was spherical, with an average size of 250 ± 3 and 460 ± 6 nm. Microbiological cultures with treatment showed 94% microbial inhibition. It was concluded that the Crescentia cujete L., leaves shoed an acceptable concentration of quercetin to be used as a useful adjuvant to enhance the reduction of NPs synthesis. The nanoparticles produced by green synthesis proved to have a positive effect to combat pathogenic microorganisms.

Mechanistic and recent updates in nano-bioremediation for developing green technology to alleviate agricultural contaminants

The rise in environmental pollutant levels in recent years is mostly attributable to anthropogenic activities such as industrial, agricultural and other activities. Additionally, these activities may produce excessive levels of dangerous toxicants such as heavy metals, organic pollutants including pesticide and herbicide chemicals, and sewage discharges from residential and commercial sources. With a focus on environmentally friendly, sustainable technology, new technologies such as combined process of nanotechnology and bioremediation are urgently needed to accelerate the cost-effective remediation process to alleviate toxic contaminants than the conventional remediation methods. Numerous studies have shown that nanoparticles possess special qualities including improved catalysis and adsorption as well as increased reactivity. Currently, microorganisms and their extracts are being used as promising, environmentally friendly catalysts for engineered nanomaterial. In the long term, this combination of both technologies called nano-bioremediation may significantly alter the field of environmental remediation since it is more intelligent, safe, environmentally friendly, economical and green. This review provides an overview of soil and water remediation techniques as well as the use of nano-bioremediation, which is made from various living organisms. Additionally, current developments related to the mechanism, model and kinetic studies for remediation of agricultural contaminants have been discussed.

Ultrasound-assisted rapid biological synthesis and characterization of silver nanoparticles using pomelo peel waste

Synthesis of silver nanoparticles by green route is an emerging technique drawing more attention recently because of several advantages over the conventional chemical ways. The overall objective of the research was focused on the green synthesis of silver nanoparticles using pomelo peel waste via a rapid and eco-friendly ultrasonic-assisted technique and their characterization. Different factors affecting the synthesis, like methodology for the preparation of extract and various treatment conditions for the synthesis, were also studied. The developed nanoparticles were characterized for their optical, molecular, microstructural, and physical properties by UV-visible spectroscopy, dynamic light scattering (DLS), zeta-potential measurements, scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR). The green synthesized nanoparticles were found almost spherical when treated at room and high temperatures and cubical when treated with ultrasonication. As obtained from the XRD studies, the size of crystallitenanoparticles was 35 to 40 nm in diameter. The EDX, FT-IR, and zeta potential analysis corroborated the role of phenolic compounds in capping and reduction of the metal ion. The capping ability of the polyphenolic component in the extract was used to achieve size stability. The nanoparticles also showed antibacterial activity against gram-negative and gram-positive bacteria, owing to the inherent antibacterial capability of silver nanoparticles.

Antimicrobial Activity of Biogenic Silver Nanoparticles from Syzygium aromaticum against the Five Most Common Microorganisms in the Oral Cavity

Syzygium aromaticum (clove) has been used as a dental analgesic, an anesthetic, and a bioreducing and capping agent in the formation of metallic nanoparticles. The main objective of this study was to evaluate the antimicrobial effect in oral microorganisms of biogenic silver nanoparticles (AgNPs) formed with aqueous extract of clove through an ecofriendly method “green synthesis”. The obtained AgNPs were characterized by UV-Vis (ultraviolet-visible spectroscopy), SEM-EDS (scanning electron microscopy–energy dispersive X-ray spectroscopy), TEM (transmission electron microscopy), and ζ potential, while its antimicrobial effect was corroborated against oral Gram-positive and Gram-negative microorganisms, as well as yeast that is commonly present in the oral cavity. The AgNPs showed absorption at 400–500 nm in the UV-Vis spectrum, had an average size of 4–16 nm as observed by the high-resolution transmission electron microscopy (HR-TEM), and were of a crystalline nature and quasi-spherical form. The antimicrobial susceptibility test showed inhibition zones of 2–4 mm in diameter. Our results suggest that AgNPs synthesized with clove can be used as effective growth inhibitors in several oral microorganisms.

Bio-Synthesized Nanoparticles in Developing Plant Abiotic Stress Resilience: A New Boon for Sustainable Approach

Agriculture crop development and production may be hampered in the modern era because of the increasing prevalence of ecological problems around the world. In the last few centuries, plant and agrarian scientific experts have shown significant progress in promoting efficient and eco-friendly approaches for the green synthesis of nanoparticles (NPs), which are noteworthy due to their unique physio-biochemical features as well as their possible role and applications. They are thought to be powerful sensing molecules that regulate a wide range of significant physiological and biochemical processes in plants, from germination to senescence, as well as unique strategies for coping with changing environmental circumstances. This review highlights current knowledge on the plant extract-mediated synthesis of NPs, as well as their significance in reprogramming plant traits and ameliorating abiotic stresses. Nano particles-mediated modulation of phytohormone content in response to abiotic stress is also displayed. Additionally, the applications and limitations of green synthesized NPs in various scientific regimes have also been highlighted.

Dyeing of cotton fabric materials with biogenic gold nanoparticles

The present work aimed at synthesizing gold nanoparticles in a biological method employing fruit peel waste dumped in the environment. The peels of Garcinia mangostana (Mangostan), were collected from the nearby tourist spot during the season. The collected fruit peels were washed, dried, powder and extracted by using boiling water and acetone. The precipitated extract was dried and powdered for further use. The dried and powdered peel extract was added to the gold solution and boiled to 80 °C and the color change is observed. The color change indicates the completion of the synthesis of gold nanoparticles. The effect of pH, gold ion concentration, peel extract powder concentration, and the temperature was tested by varying the parameters. The biosynthesized nanoparticles were characterized using the UV–Vis spectrophotometer to identify the surface plasmon resonance peaks corresponding to gold nanoparticles. The bio-moieties responsible for the synthesis of gold nanoparticles were identified using the Fourier Transform Infra-Red Spectroscopy. The crystalline nature was detected by using an X-Ray Diffractometer. Atomic Force Microscope viewed the 3D surface image of the gold nanoparticle. The shape and morphology of the nanoparticle were identified by using a Field Emission Scanning Electron Microscope. The active compounds for gold nanoparticle synthesis were identified using Gas Chromatography-Mass Spectrometry. The gold nanoparticle was synthesized in various colors and used for dyeing cotton fabrics. The dyed cotton materials were exposed to various stress conditions to determine the color fastening.

Understanding and advancement in gold nanoparticle targeted photothermal therapy of cancer

The present communication summarizes the importance, understanding and advancement in the photothermal therapy of cancer using gold nanoparticles. Photothermal therapy was used earlier as a single line therapy, but using a combination of photothermal therapy with other therapies like immunotherapy, chemotherapy, photodynamic therapy; efficient therapy management can be achieved. As it was discussed in many studies that gold nanoparticles are treated as idyllic photothermal transducers due to their structural dimensions, which enables them to strongly absorb near infrared light. Gold nanoparticles which are mediated for photothermal therapy can warn cancer cells to chemotherapy, regulate genes and immunotherapy by enhancing the cell permeability and intracellular delivery. The necrosis process and apoptosis depend on the power of laser and temperature within the cancerous tissues which are reached during irradiation. Cells death mechanism is also important because the cells which died through the process of necrosis can endorse secondary tumor growth while the cells which died through apoptosis may provoke the immune response to inhibit the development of secondary tumor growth. To decrease the in vivo barriers, gold nanostructures are again modified with targeting ligand and bio-responsive linker. The manuscript summarizes that the use of gold nanoparticles is capable of inhibiting the growth of cancerous cells by using photothermal therapy which has lesser adverse effects compared to other line therapies.

Phytotoxicity of green synthesized silver nanoparticles on Camelina sativa L

Due to the increased production and release of silver nanoparticles (AgNPs) in the environment, the concerns about the possibility of toxicity and oxidative damage to plant ecosystems should be considered. In the present study, the effects of different concentrations of AgNPs (0, 0.5, 1, 2, 3 and 4 g/L) synthesized using the extract of camelina (Camelina sativa) leaves on the growth and the biochemical traits of camelina seedlings were investigated. The results showed that AgNPs significantly increased Ag accumulation in the roots and shoots which decreased the growth and photosynthetic pigments of camelina seedlings. The highest decrease in the height and total dry weight was observed by 53.1 and 61.8% under 4 g/L AgNPs, respectively over control plants. AgNPs application over 2 g/L enhanced the accumulation of proline, malondialdehyde, hydrogen peroxide and methylglyoxal, and up-regulated the activity of antioxidant enzymes (superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase) and glyoxalase (glyoxalase I and II) system which indicates oxidative stress induction in camelina seedlings. Moreover, AgNPs reduced ASA and GSH contents and increased DHA and GSSG contents, hence disrupting the redox balance. These results showed that AgNPs at 4 g/L had the most toxic effects on the camelina growth. Therefore, increasing oxidative stress markers and the activity of antioxidant enzymes and enzymes involved in glyoxalase system indicated the oxidative stress induced by AgNPs treatments over 2 g/L as well as the induction of antioxidant defense systems to combat AgNPs-induced oxidative stress.

Green Synthesis of Magnetic Nanoparticles Using Satureja hortensis Essential Oil toward Superior Antibacterial/Fungal and Anticancer Performance

The biological synthesis of nanoparticles, due to their environmental and biomedical properties, has been of particular interest to scientists and physicians. Here, iron nanoparticles (FeNPs) were synthesized using Satureja hortensis essential oil. Then, the chemical, functional, and morphological properties of these nanoparticles were characterized by typical experiments such as Uv-Vis, FTIR, XRD, FE-SEM, PSA, zeta potential, EDX, and EDX mapping. The results indicated Fe nanoparticles' formation with a cubic morphological structure and a particle size in the range of 9.3-27 nm. The antimicrobial effects of these nanoparticles were further evaluated using disc diffusion, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum fungal concentration (MFC) against two gram-positive bacterial strains (Staphylococcus aureus and Corynebacterium glutamicum), two gram-negative bacterial strains (Pseudomonas aeruginosa and Escherichia coli), and one fungus species Candida albicans. The results showed that green-synthesized Fe nanoparticles possessed higher antimicrobial properties than Satureja hortensis essential oil against selected pathogenic microorganisms, especially Gram-negative bacteria. Finally, the anticancer effect of these Fe nanoparticles was investigated on human cancer cells, K-562, and MCF-7, by the MTT assay. The results showed the anticancer effect of these nanoparticles against selected cell lines.

Green silver nano-particles: synthesis using rice leaf extract, characterization, efficacy, and non-target effects

Green synthesis of silver nano-particles (AgNPs) from silver nitrate was carried out using purple-colored rice leaves' extracts containing higher phenols, anthocyanins, and flavonoids. The efficacy of synthesized AgNPs was tested against rice diseases and investigation was carried out to check negative effect of AgNPs on soil microbes. Substantial reduction of total anthocyanins, total phenols, and total flavonoids was observed in reaction mixture during AgNP formation indicating the role of secondary metabolites on AgNP formation and stabilization. Scanning electron microscopy coupled with energy-dispersive spectroscopic images and FTIR spectral analysis of AgNPs confirmed the presence of elemental silver encapped by biomolecules. The optimized reaction parameters for synthesis of AgNPs from silver nitrate were (a) 48 h of incubation, (b) 9:1 (v/v) 1 mM AgNO3:plant extract, and (c) room temperature at 20-30 °C. Zeta potential and hydrodynamic particle sizes of synthesized AgNPs were ranged between - 16.61 to - 29.45 mV and 36-107 nm, respectively, at different time of incubation. AgNPs could control effectively Rhizoctonia solani and Xanthomonas oryzae pv. Oryzae and Helminthosporium oryzae. AgNPs at higher concentration could cause negative effect on microbial biomass carbon and soil enzymes for distant future. But the negative effects of AgNP solution (10% of 1 mM AgNPs) were comparable to commercial fungicide, carbendazim. The synthesized AgNPs with desirable characters were effective against a number of disease-causing pathogens in rice, and it can be recommended as broad-spectrum pesticide.

Characterization and Pharmacological Efficacy of Silver Nanoparticles Biosynthesized Using the Bark Extract of Garcinia Kola

The delinquent peril of bacterial infections affecting human kind is becoming unbearable. This study was embarked on to investigate the antimicrobial activity of biosynthesized silver nanoparticles (AgNPs) using Garcinia kola bark extract against some bacteria strains. Fresh barks of Garcinia kola were obtained from the “Gbeleju” farm land in Irele town in Ondo state region of Nigeria. Exactly 0.4 g of previously pulverized bark of Garcinia kola was immersed into 20 mL of distilled water and heated at 60–70°C for 10 minutes yielding the extract. The biosynthesized nanoparticle was characterized with UV spectroscope, Fourier infrared spectroscope (FTIR), transmission electron microscope (TEM), and energy dispersive X-Ray analyzer (EDX). Then, 0.2 g of the silver nanoparticles was dissolved in 2 ml of water to yield 100 mg/ml of the stock solution which was further diluted for the antibacterial analysis via the disc diffusion method. The result obtained from the analytical characterization of the biosynthesized silver nanoparticles revealed a spherical particle shape, particle size in the range of 12.23 to 27.90 nm with an average size of 20.07 nm via TEM analysis. The FTIR analysis confirmed the presence of -OH functional group for the stabilization of the silver nanoparticles formed due to the broad peak at wavelength 3324.52 and 3344.21 cm−1. The EDX analysis revealed carbon, nitrogen, oxygen, aluminum, potassium, copper, and silver as the elements present in the nanoparticles. Results obtained from the antibacterial screening of the biosynthesized AgNPs showed inhibitory potential that are capable of obstructing the growth of the test bacteria. This investigation ascertained the biosynthesized AgNPs as a remedy for curing bacterial infections and also a promising source for novel antibacterial agent.

Synthesis of Various Size Gold Nanoparticles by Chemical Reduction Method with Different Solvent Polarity

Complicated and strict protocols are followed to tune the size of gold nanoparticles (GNPs) in chemical synthesis methods. In this study, we address the polarity of solvents as a tool for tailoring the size of GNPs in the chemical reduction method. The effects of varying polarity index of the reaction medium on synthesizing gold nanoparticles by chemical reduction method have been investigated. Ethanol as a polar solvent, ethanol-water mixture as reaction medium, L-ascorbic acid as reducing agent, and polyvinylpyrrolidone as stabilizer were used to synthesize GNPs. The polarity index of the reaction medium was adjusted by changing the volume ratio of ethanol to water. UV-Vis, dynamic light scattering (DLS), and transmission electron microscopy (TEM) characterizations reveal that the growth of nanoparticles was gradually increased (~ 22 to 219 nm hydrodynamic diameter) with decreasing value of polarity index of the reaction medium (~ 8.2 to 5.2). Furthermore, the high polarity index of the reaction medium produced smaller and spherical nanoparticles, whereas lower polarity index of reaction medium results in bigger size of GNPs with different shapes. These results imply that the mechanistic of the growth, assembly, and aggregation phenomena of ligand or stabilizer-capped GNPs strongly rely on the polarity of solvent molecules. Using the proposed methodology, wide size range of GNPs with different morphology sizes can be synthesized by simply modulating the volume percentage of organic solvent in the reaction medium.

Single-step green route synthesis of Au/Ag bimetallic nanoparticles using clove buds extract: Enhancement in antioxidant bio-efficacy and catalytic activity

In present work, we demonstrate a single step environmentally benign approach to synthesize Au/Ag bimetallic nanoparticles (BMNPs) using aqueous extract of Clove buds for the first time. Clove bud's (CB) extract has proficiency to act as a reducing and stabilizing agent for the formation of Au/Ag BMNPs. In presence of extract, Au^III and Ag^I are reduced competitively within same solution and produce Au/Ag alloy NPs. The kinetics besides the formation of NPs was studied using UV-visible spectroscopy and efficiency of the extract was monitored by varying contact time, temperature, pH and extract concentration. The electron microscopic studies revealed the presence of NPs with peculiar morphology at alkaline pH. Further, the existence of Au and Ag atoms was investigated using energy dispersive X-ray (EDX), X-ray diffraction (XRD) and cyclic voltammetry (CV) techniques. Fourier transform infrared spectroscopy (FTIR) showed that Eugenol in the extract is mainly responsible for the production of NPs which are also surrounded by various phytochemicals. Zeta potential of all the NPs is found to be negative which prevents their agglomeration due to inter-repulsion and the biosynthesized Au/Ag BMNPs revealed greater catalytic efficiency for the degradation of methyl orange (MO), methylene blue (MB) and reduction of p-nitrophenol (p-NP). Significant enhancement induced by BMNPs compared to individual monometallic nanoparticles (MMNPs) was assigned to the synergistic effect of MMNPs and coating of phytochemicals present in the CB extract.

Antibacterial, anticoagulant and cytotoxic evaluation of biocompatible nanocomposite of chitosan loaded green synthesized bioinspired silver nanoparticles

Present work reports the green synthesis of chitosan functionalized silver nanoparticles (CS-AgNPs) using ethanolic buds extract of Sygyzium aromaticum. CS-AgNPs were characterized physically, evaluated for antibacterial, anticoagulant and antiplatelet activities, and toxicity profile. The physical characterization of CS-AgNPs was done by UV/vis, SEM, TEM, FTIR and EDX. The sphericity was found uniform. FTIR and EXD showed noninterfering few impurities. The antibacterial activity against VRSA (ZI, 23.2 ± 0.51 mm) and MRSA (ZI, 25.8 ± 0.32 mm) were determined. The rise in bleeding and thromboplastin was observed highly significant while increased in prothrombin and activated partial prothrombin time in significant manner at both the doses of CS-AgNPs (0.025 mg/kg and 0.05 mg/kg). Reduction in the levels of fibrinogen was also highly significant. Platelet aggregation decreased at high dose of CS-AgNPs i.e. 55.14 ± 8.25% (arachidonic acid) and 13.06 ± 2.17% (collagen). Thrombin antithrombin (TAT) complex activity was found highest for CS-AgNPs. Cytotoxicity was assessed using HeLa cell lines (LC₅₀; 125 μg/ml) and brine shrimp lethality tests (LC_50; 518 μg/ml). The work suggests that green synthesized chitosan functionalized silver nanoparticles may be utilized as an effective antibacterial agent and anticoagulant with low toxicity. The current findings will open a new window for nanomedicine development and future clinical application.

Microwave-Assisted Green Synthesis and Characterization of Silver Nanoparticles Using Melia azedarach for the Management of Fusarium Wilt in Tomato

These days, research in agriculture is focusing on the theme of sustainability along with protection of agriculture produce. Nanotechnology in the agriculture sector aims for the enhancement of agricultural produce and the reduction of pesticides through providing innovative agrochemical agents and their novel delivery mechanisms. The current investigation involved the green synthesis of silver nanoparticles (AgNPs) from the aqueous leaf extract of Melia azedarach by following a microwave-assisted method to control Fusarium oxysporum, the causal agent of tomato wilt. Biosynthesized Melia leaf extract (MLE)-AgNPs were characterized by UV-visible spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray (EDX) spectrometry, dynamic light scattering (DLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and zeta potential analysis. The intensity of the peak at 434 nm in UV-vis spectra, attributed to the surface plasmon resonance of MLE-AgNPs, changes with reaction parameters. TEM exhibits spherical shaped nanoparticles with an average particle size range from 12 to 46 nm. Efficient inhibition of F. oxysporum, the causal agent of tomato wilt, was achieved after exposure to MLE-AgNPs both in vivo and in vitro. In vitro studies exhibited repressed fungal mycelial growth with 79-98% inhibition as compared to the control. Significant increases in growth parameters of tomato seedlings were observed after treatment with biosynthesized nanoparticles as compared to F. oxysporum-infected plants grown without them under greenhouse conditions. Furthermore, SEM imaging was done to reveal the prominent damage on the cell wall of hyphae and spores after MLE-AgNP treatment. Propidium iodide (PI) staining of mycelium indicated the extent of cell death, causing irretrievable damage and disintegration of cellular membranes by altering the membrane permeability. Also, 2',7'-dichlorofluorescin diacetate (DCFH-DA) fluorescence specifies intracellular reactive oxygen species (ROS) production in F. oxysporum after treatment with MLE-AgNPs. The current investigation suggested that biosynthesized nanoparticles can revolutionize the field of plant pathology by introducing an environment-friendly approach for disease management and playing a potential part in agriculture industry. However, to date, little work has been done to integrate nanotechnology into phytopathology so, this area of research is in need of adoption and exploration for the management of plant diseases.

Modulation of secondary metabolite profiles by biologically synthesized MgO/perlite nanocomposites in Melissa officinalis plant organ cultures

In this work, biological synthesis of MgO/perlite nanocomposites (NCs) besides their effects on morphology and secondary metabolite profiles of Melissa officinalis plant organ cultures were evaluated. MgO NPs were immobilized on the surface of nanoperlite using M. officinalis extract as a capping agent. The as-synthesized MgO/perlite NCs were characterized by using FTIR, XRD, SEM, EDS and DLS. The average particle size of nanoperlite and MgO/perlite NCs was about 10 and 30 nm, respectively. Morphological observations showed that nanoperlite and MgO/perlite NCs had no effect on root number, as well as root and shoot length. None of the applied concentrations of perlite and MgO/perlite NCs could significantly increase the growth parameters in comparison to the control, except for 150 mg/L of nanoperlite which caused an increase in the shoot number. Although, the contents of chlorophyll and carotenoids were not affected, the maximum content of volatile compounds obtained at 100 of MgO/perlite NCs. Rosmarinic acid was detected in shoots, which treated with 25-100 mg/L of perlite and 25, 50 and 150 mg/L of MgO/perlite NCs. Our results provided the evidence that nanoperlite and MgO/perlite NCs at specific levels may act as a novel elicitor for in vitro biosynthesis of valuable secondary metabolites.

3D hybrid structures based on biomimetic membranes and Caryophyllus aromaticus - "green" synthesized nano-silver with improved bioperformances

The paper describes an innovative bio-design of some hybrid nanoarchitectures containing bioartificial membranes and silver nanoparticles phytogenerated by using a natural extract Caryophyllus aromaticus (cloves) that contains many bioactive compounds. Two kinds of liposomes with and without chlorophyll a (Chla) obtained through thin film hydration method were used to achieve bio-green-generated hybrids by a simple, cost effective bottom-up approach. The characteristic peaks of CE-nAg monitored by UV-Vis absorption have firstly demonstrated the biohybrids formation. The slightly blue shift and fluorescence quenching observed by fluorescence emission spectra highlighted the formation of hybrid systems by biointeraction between lipid vesicles and silver nanoparticles. The incorporation of silver nanoparticles in lipid vesicles resulted in significant changes of FT-IR spectra of liposomes, indicating a reorganization of biomimetic membranes. All the microscopic methods (SEM, AFM and TEM) confirmed the biosynthesis of "green" AgNPs together with associated biohybrids, their spherical and quasi-spherical shapes with nano-scaled size. By TEM assay it was shown that CE-nAg are surrounded by petal like cloud structures that consist of biopolymers like proteins or polysaccharides and other phytochemicals arising from clove extract. EDS spectra confirmed the formation of phyto-nanoAg and also the presence of silver in the biohybrids. In addition, Selected Area Electron Diffraction showed characteristic polycrystalline ring patterns for a cubic structure of the clove-generated AgNPs. The hybrid materials showed efficient physical stability,i.e. ξ value of -28.0 mV (for biohybrids without Chla, BH) and of -31.7 mV (for biohybrids labelled with Chla, Chla-BH), assured by strong electrostatic repulsive forces between particles. The "green" nano-silver particles (CE-nAg) showed remarkable antioxidant activity (AA = 90.2%). The biohybrids loaded with clove-AgNPs proved to be more effective, scavenging about 98.8% of free radicals (in case of Chla-BH), and of 92.6% (in case of BH). The antibacterial effectiveness showed that green AgNPs combine in a synergistic manner the antibacterial properties of clove extract with those of silver, resulting in an enhancement of inhibition diameter, by 20%. Chla-BH proved to be more potent against Escherichia coli, than BH, exhibiting an inhibition diameter of 42 mm. Regarding the in vitro cytotoxicity against tumour cells, the CE-nAg concentration significantly influenced the cell viability, i.e. IC₅₀ was 3.6% (v/v) for HT-29 cells. Chla-BH was more effective against HT-29 cancer cells at the concentrations ranging from 0 to 18% (v/v), when the normal cells were not affected. Clove-generated AgNPs exhibited haemolytic activity against hRBCs, while the biohybrids were haemocompatible. The action mechanism on the two cell lines (mouse fibroblast L929 cells and human colorectal adenocarcinoma HT-29 cells) investigated by fluorescence microscopy demonstrated that CE-nAg killed almost all the cells (94%) through necrosis at a concentration of 33.4% (v/v). The treatment of HT-29 cells with BH resulted in: 71.5% viable cells, 19.5% apoptotic and only 9% necrotic cells, while in the case of Chla-BH treatment, only 77.5% cells were viable, 16% cells were apoptotic and 6.5% were necrotic. In this way, the developed silver-based nanoparticles can represent viable promoters to develop new biohybrids with improved features, e.g. antioxidant and antibacterial effectiveness, haemolytic activity and greater specificity towards tumour cells.

'Green' synthesis of metals and their oxide nanoparticles: applications for environmental remediation

In materials science, “green” synthesis has gained extensive attention as a reliable, sustainable, and eco-friendly protocol for synthesizing a wide range of materials/nanomaterials including metal/metal oxides nanomaterials, hybrid materials, and bioinspired materials. As such, green synthesis is regarded as an important tool to reduce the destructive effects associated with the traditional methods of synthesis for nanoparticles commonly utilized in laboratory and industry. In this review, we summarized the fundamental processes and mechanisms of “green” synthesis approaches, especially for metal and metal oxide [e.g., gold (Au), silver (Ag), copper oxide (CuO), and zinc oxide (ZnO)] nanoparticles using natural extracts. Importantly, we explored the role of biological components, essential phytochemicals (e.g., flavonoids, alkaloids, terpenoids, amides, and aldehydes) as reducing agents and solvent systems. The stability/toxicity of nanoparticles and the associated surface engineering techniques for achieving biocompatibility are also discussed. Finally, we covered applications of such synthesized products to environmental remediation in terms of antimicrobial activity, catalytic activity, removal of pollutants dyes, and heavy metal ion sensing.

Plant-based metallic nanoparticles as potential theranostics agents: bioinspired tool for imaging and treatment

Theranostic approach provides us a platform where diagnosis and treatment can be carried out simultaneously. Biosynthesis of theranostic-capable nanoparticles (NPs) can be carried out by phytoconstituents present inside the plants that can act as capping as well as stabilising agents by offering several advantages over chemical and physical methods. This article highlights the theranostic role of NPs with emphasis on potential of plants to produce these NPs through ecofriendly approach that is called 'Green synthesis'. Biosynthesis, advantages, and disadvantages of plant-based theronostics have been discussed for better understanding. Moreover, this article has highlighted the approaches required to optimise the plant-mediated synthesis of NPs and to avoid the toxicity of these agents. Anticipating all of the challenges, the authors expect biogenic NPs can appear as potential diagnostic and therapeutic agents in near future.

Electrospun nanofibers decorated with bio-sonochemically synthesized gold nanoparticles as an ultrasensitive probe in amalgam-based mercury (II) detection system

In this study, bio-ultrasound-assisted synthesized gold nanoparticles using Gracilaria canaliculata algae have been immobilized on a polymeric support and used as a glassy probe chemosensor for detection and rapid removal of Hg²⁺ ions. The function of the suggested chemosensor has been explained based on gold-amalgam formation and its catalytic role on the reaction of sodium borohydride and rhodamine B (RhB) with fluorescent and colorimetric sensing function. The catalyzed reduction of RhB by the gold amalgam led to a distinguished color change from red and yellow florescence to colorless by converting the amount of Hg²⁺ deposited on Au-NPs. The detection limit of the colorimetric and fluorescence assays for Hg²⁺ was 2.21 nM and 1.10 nM respectively. By exposing the mentioned colorless solution to air for at least 2 h, unexpectedly it was observed that the color and fluorescence of RhB were restored. Have the benefit of the above phenomenon a recyclable and portable glass-based sensor has been provided by immobilizing the Au-NPs and RB on the glass slide using electrospinning. Moreover, the introduced combinatorial membrane has facilitated the detection and removal of Hg²⁺ ions in various Hg (II)-contaminated real water samples with efficiency of up to 99%.

Bio-functionalized gold nanoparticles: Benign effect in Sprague-Dawley rats by intravenous administration

Gold nanoparticles offer a great promise in clinical research. Despite various applications of the metal nanoparticles it is challenging to implement in vivo in clinical applications. This aspect is deprived of understanding the biological mechanisms that occurs in the cells. In this report we have evaluated application of AuNP on the safety profile at different doses (100, 200, and 500 μg/kg Bwt/day) on intravenous administration in rats regularly for 28 days. The study was performed based on the OECD test guideline 407. No clinical signs and mortalities were observed in any groups of rat treated with AuNP. No evidence of toxicity was observed in any of the diverse studies performed which is noteworthy. The study includes survival, behavior, animal weight, organ morphology, blood biochemistry and tissue histology. The results indicate that tissue accumulation pattern of gold nanoparticles depends on the surface, size and doses of the nanoparticle. The accumulation of the particles does not produce subacute physiological damage.