Biogenic synthesis of multi-applicative silver nanoparticles by using Ziziphus Jujuba leaf extract

Ziziphus jujuba: Applications in the Pharmacy and Food Industry

Ziziphus jujuba has been used since ancient times in traditional Eastern medicine. It is widely cultivated in numerous countries between the tropical and temperate climatic zones due to its high ecological plasticity and resilience to adverse weather. The different classes of chemical compounds contained in the plant are the reason for its medicinal properties. Research shows that every part of Ziziphus jujuba, the leaves, fruits and seeds, demonstrate therapeutic properties. This review focuses on the chemical composition in order to establish the relationship between the plant and its clinical use. Various biological effects are summarized and discussed: anticancer, anti-inflammatory, immunostimulating, antioxidant, hepatoprotective, gastrointestinal, etc. Apart from medicinal uses, the fruits of Ziziphus jujuba are edible and used in fresh and dried form. This literature review reveals possible medical applications of Ziziphus jujuba and its great potential for improving the diet of people in areas where the plant is abundant.

Green Preparation and Antibacterial Activity Evaluation of AgNPs-Blumea balsamifera Oil Nanoemulsion

Bacterial infection is a thorny problem, and it is of great significance to developing green and efficient biological antibacterial agents that can replace antibiotics. This study aimed to rapidly prepare a new type of green antibacterial nanoemulsion containing silver nanoparticles in one step by using Blumea balsamifera oil (BBO) as an oil phase and tea saponin (TS) as a natural emulsifier and reducing agent. The optimum preparation conditions of the AgNPs@BBO-TS NE were determined, as well as its physicochemical properties and antibacterial activity in vitro being investigated. The results showed that the average particle size of the AgNPs@BBO-TS NE was 249.47 ± 6.23 nm, the PDI was 0.239 ± 0.003, and the zeta potential was -35.82 ± 4.26 mV. The produced AgNPs@BBO-TS NE showed good stability after centrifugation and 30-day storage. Moreover, the AgNPs@BBO-TS NE had an excellent antimicrobial effect on Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. These results demonstrated that the AgNPs@BBO-TS NE produced in this study can be used as an efficient and green antibacterial agent in the biomedical field.

C. S, Anil VS, Raghavan S. Phytosynthesis of silver nanoparticles using aqueous sandalwood (Santalum album L.) leaf extract: Divergent effects of SW-AgNPs on proliferating plant and cancer cells

The biogenic approach for the synthesis of metal nanoparticles provides an efficient eco-friendly alternative to chemical synthesis. This study presents a novel route for the biosynthesis of silver nanoparticles using aqueous sandalwood (SW) leaf extract as a source of reducing and capping agents under mild, room temperature synthesis conditions. The bioreduction of Ag+ to Ago nanoparticles (SW-AgNPs) was accompanied by the appearance of brown color, with surface plasmon resonance peak at 340-360 nm. SEM, TEM and AFM imaging confirm SW-AgNP's spherical shape with size range of 10-32 nm. DLS indicates a hydrodynamic size of 49.53 nm with predominant negative Zeta potential, which can contribute to the stability of the nanoparticles. FTIR analysis indicates involvement of sandalwood leaf derived polyphenols, proteins and lipids in the reduction and capping of SW-AgNPs. XRD determines the face-centered-cubic crystalline structure of SW-AgNPs, which is a key factor affecting biological functions of nanoparticles. This study is novel in using cell culture methodologies to evaluate effects of SW-AgNPs on proliferating cells originating from plants and human cancer. Exposure of groundnut calli cells to SW-AgNPs, resulted in enhanced proliferation leading to over 70% higher calli biomass over control, enhanced defense enzyme activities, and secretion of metabolites implicated in biotic stress resistance (Crotonyl isothiocyanate, Butyrolactone, 2-Hydroxy-gamma-butyrolactone, Maltol) and plant cell proliferation (dl-Threitol). MTT and NRU were performed to determine the cytotoxicity of nanoparticles on human cervical cancer cells. SW-AgNPs specifically inhibited cervical cell lines SiHa (IC50-2.65 ppm) and CaSki (IC50-9.49 ppm), indicating potential use in cancer treatment. The opposing effect of SW-AgNPs on cell proliferation of plant calli (enhanced cell proliferation) and human cancer cell lines (inhibition) are both beneficial and point to potential safe application of SW-AgNPs in plant cell culture, agriculture and in cancer treatment.

Comparative Effect of Chemical and Green Zinc Nanoparticles on the Growth, Hematology, Serum Biochemical, Antioxidant Parameters, and Immunity in Serum and Mucus of Goldfish, Carassius auratus (Linnaeus, 1758)

Recently, nano feed supplement research has great attention to improving healthy aquatic production and improving the aquatic environment. With the aims of the present study, chemical and green synthesized nanoparticles are characterized by various instrumentation analyses, namely UV-Vis spectrophotometry (UV-Vis), X-ray diffraction (XRD), Fourier transform infra-red (FTIR) spectroscopy, and scanning electron microscope (SEM). After characterization analysis of these nanoparticles utilized in aquatic animals, the composition ratio is as follows: controls (without ZnO-NPs (0 mg/L)), T1 (0.9 mg/L ZnO-NPs), T2 (1.9 mg/L ZnO-NPs), T3 (0.9 mg/L GZnO-NPs), T4 (1.9 mg/L GZnO-NPs). SEM investigation report demonstrates that the structure of the surface of green synthesized zinc oxide nanoparticles (GZnO-NPs) was conical shape and the size ranging was from 60 to 70 nm. Concerning hematological parameters, the quantity of hemoglobin increased in different doses of green zinc nanoparticles, but the values of MCV and MCH decreased somewhat. However, this decrease was the highest in the T2 group. Total protein and albumin decreased in T2 and triglyceride, cholesterol, glucose, cortisol, creatinine, and urea increased, while in T3 and T4 groups, changes in biochemical parameters were evaluated as positive. Mucosal and serum immunological parameters in the T2 group showed a significant decrease compared to other groups. In zinc nanoparticles, with increasing dose, oxidative damage is aggravated, so in the T2 group, a decrease in antioxidant enzymes and an increase in MDA were seen compared to other groups. In this regard, the concentration of liver enzymes AST and ALT increased in the T2 group compared with control and other groups. This can confirm liver damage in this dose compared with control and other groups. This research work suggests that green synthesized form of zinc nanoparticles in higher doses have less toxic effects in comparison to the chemical form of zinc nanoparticles and can act as suitable nutrient supplements in aquatic animals.

Metallic and non-metallic nanoparticles from plant, animal, and fisheries wastes: potential and valorization for application in agriculture

Global agriculture is facing tremendous challenges due to climate change. The most predominant amongst these challenges are abiotic and biotic stresses caused by increased incidences of temperature extremes, drought, unseasonal flooding, and pathogens. These threats, mostly due to anthropogenic activities, resulted in severe challenges to crop and livestock production leading to substantial economic losses. It is essential to develop environmentally viable and cost-effective green processes to alleviate these stresses in the crops, livestock, and fisheries. The application of nanomaterials in farming practice to minimize nutrient losses, pest management, and enhance stress resistance capacity is of supreme importance. This paper explores innovative methods for synthesizing metallic and non-metallic nanoparticles using plants, animals, and fisheries wastes and their valorization to mitigate abiotic and biotic stresses and input use efficiency in climate-smart and stress-resilient agriculture including crop plants, livestock, and fisheries.

Biogenic silver nanoparticles as antifungal agents

In recent years, an increase in multidrug-resistant fungal strains has been observed, which, together with the limited number of clinically available antifungal agents, highlights the need for the development of new antifungal agents. Due to the proven antifungal activity of silver nanoparticles (AgNPs), there is a growing interest in their use in the treatment of fungal infections. Nanoparticles are usually synthesised through a variety of physical and chemical processes that are costly and pollute the environment. For this reason, biogenic synthesis is emerging as an environmentally friendly technology and new strategies are increasingly based on the use of biogenic AgNPs as antifungal agents for clinical use. The aim of this review is to compare the antifungal activity of different biogenic AgNPs and to summarise the current knowledge on the mechanisms of action and resistance of fungi to AgNPs. Finally, a general analysis of the toxicity of biogenic AgNPs in human and veterinary medicine is performed.

Studies of surface plasmon resonance of silver nanoparticles reduced by aqueous extract of shortleaf spikesedge and their catalytic activity

This study describes the synthesis of silver nanoparticles (AgNPs) using shortleaf spikesedge extract (SSE) to reduce AgNO₃. Visual observation, in addition to analyses of UV-vis, EDX, XRD, FTIR, and TEM was employed to monitor the formation of AgNPs. The effects of SSE concentration, AgNO₃ concentration, reaction time, pH, and temperature on the synthesis of AgNPs were studied based on the surface plasmon resonance (SPR) band. From the TEM image, highly-scattered AgNPs of quasi-spherical shape with an average particle size of 17.64 nm, were observed. For the catalytic study, the reduction of methylene blue (MB) was evaluated using two systems. A detailed batch study of the removal efficiency (%RE) and kinetics was done at an ambient temperature, various MB initial concentrations, and varying reaction time. Employing the electron relay effect in System 2, the batch study clearly highlighted the significant role of AgNPs in boosting the catalytic activity for MB removal. At 30-100 mg/L initial concentrations, MB was reduced by 100% in a very short reaction time between 1.5 and 5.0 mins. The kinetic data best fitted the pseudo-first-order model with a maximum reaction rate of 2.5715 min^-1. These findings suggest the promising application of AgNPs in dye wastewater treatment.The SSE-driven AgNPs were prepared using unwanted dried biomass of shortleaf spikesedge extract (SSE) as a reducing as well as stabilizing agent. Employing the electron relay effect, the batch study clearly highlighted the significant role of SSE-driven AgNPs in boosting the catalytic activity for MB removal. At 30-100 mg/L initial concentrations, MB was reduced by 100% in a very short reaction time between 1.5 and 5.0 mins. In this sense, SSE-driven AgNPs acted as an electron relay point that behaves alternatively as acceptor and donor of electrons. The findings revealed the good catalytic performance of SSE-driven AgNPS, proving their viability for dye wastewater treatment.

On Recent Developments in Biosynthesis and Application of Au and Ag Nanoparticles from Biological Systems

Gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) are extensively studied nanoparticles (NPs) and are known to have profound applications in medicine. The researcher made continuous efforts for the environmental-friendly and economical methods, such as biogenic methods known as green synthesis. There are many strategies for separating and applying gold (Au) and silver (Ag) nanoparticles, of which biological routes have emerged as efficient, low-cost, and environmentally friendly techniques. This review focuses on recent developments of green synthesized AuNPs and AgNPs using biogenic sources such as algae, animals, plants, microbes, bacteria, fungi, and so on. Hence, it discusses their numerous biomedical applications and separating Au and Ag nanoparticles from plants, bacteria, fungi, and algae.

Nanoparticle classification, physicochemical properties, characterization, and applications: a comprehensive review for biologists

Interest in nanomaterials and especially nanoparticles has exploded in the past decades primarily due to their novel or enhanced physical and chemical properties compared to bulk material. These extraordinary properties have created a multitude of innovative applications in the fields of medicine and pharma, electronics, agriculture, chemical catalysis, food industry, and many others. More recently, nanoparticles are also being synthesized ‘biologically’ through the use of plant- or microorganism-mediated processes, as an environmentally friendly alternative to the expensive, energy-intensive, and potentially toxic physical and chemical synthesis methods. This transdisciplinary approach to nanoparticle synthesis requires that biologists and biotechnologists understand and learn to use the complex methodology needed to properly characterize these processes. This review targets a bio-oriented audience and summarizes the physico–chemical properties of nanoparticles, and methods used for their characterization. It highlights why nanomaterials are different compared to micro- or bulk materials. We try to provide a comprehensive overview of the different classes of nanoparticles and their novel or enhanced physicochemical properties including mechanical, thermal, magnetic, electronic, optical, and catalytic properties. A comprehensive list of the common methods and techniques used for the characterization and analysis of these properties is presented together with a large list of examples for biogenic nanoparticles that have been previously synthesized and characterized, including their application in the fields of medicine, electronics, agriculture, and food production. We hope that this makes the many different methods more accessible to the readers, and to help with identifying the proper methodology for any given nanoscience problem.

Phyto-Capped Ag Nanoparticles: Green Synthesis, Characterization, and Catalytic and Antioxidant Activities

Using a simple approach, silver nanoparticles (Ag NPs) were synthesized from green coffee bean extract. The optical color change from yellowish to reddish-brown of the green-produced Ag NPs was initially observed, which was confirmed by the UV-Visible spectrophotometer’s surface plasmonic resonance (SPR) bands at 329 and 425 nm. The functional groups of green coffee-capped Ag NPs (GC-capped Ag NPs) were studied using a Fourier transform infrared spectrometer, revealing that Ag NPs had been capped by phytochemicals, resulting in excellent stability, and preventing nanoparticle aggregation. The presence of elemental silver is confirmed by energy dispersive X-ray analysis. In addition to the measurement of the zeta potential of the prepared GC-capped Ag NPs, the size distribution is evaluated by the dynamic light scattering. Depending on the nano-morphological study, the particle diameter of Ag NPs is 8.6 ± 3.5 nm, while the particle size of GC-capped Ag NPs is 29.9 ± 4.3 nm, implying the presence of well-dispersed nanospheres with an average capsulation layer of thickness 10.7 nm. The phyto-capped Ag NPs were found to be crystalline, having a face-centered cubic (FCC) lattice structure and Ag crystallite size of ~7.2 nm, according to the XRD crystallographic analysis. The catalytic performance of phyto-capped Ag NPs in the removal of methylene blue dye by sodium borohydride (NaBH₄) was investigated for 12 min to reach a degradation efficiency of approximately 96%. The scavenging activities of 2,2-Diphenyl-1-picrylhydrazyl (DPPH) free radicals are also examined in comparison to previously reported Ag-based nano-catalysts, demonstrating a remarkable IC₅₀ of 26.88 µg/mL, which is the first time it has been recorded.

Bio-mimetic synthesis of catalytically active nano-silver using Bos taurus (A-2) urine

Herein we have synthesized silver nanoparticles (Ag NPs) using liquid metabolic waste of Bos taurus (A-2 type) urine. Various bio-molecules present in cow urine, are effectively used to reduce silver (Ag) ions into silver nanoparticles in one step. This is bio-inspired electron transfer to Ag ion for the formation of base Ag metal and is fairly prompt and facile. These nanoparticles act as a positive catalyst for various organic transformation reactions. The structural, morphological, and optical properties of the as-synthesized Ag NPs are widely characterized by X-ray diffraction spectroscopy, ultraviolet–visible spectroscopy, scanning electron microscope, Fourier transmission infra-red spectroscopy, and atomic force microscopy. The as-synthesized bio-mimetic Ag NPs show potential activity for several reduction reactions of nitro groups. The Ag NPs were also used for degradation of hazardous dyes such as Methylene blue and Crystal violet with good degradation rate constant.

Antimicrobial and cytotoxic activity of green synthesis silver nanoparticles targeting skin and soft tissue infectious agents

Combining traditional medicine with nanotechnology therefore opens the door to innovative strategies for treating skin and soft tissue infections (SSTIs) and also contributes to the fight against the rise of antimicrobial resistance. Acanthospermum australe (Loefl.) Kuntze is a medicinal plant used by indigenous peoples in northeastern Argentina to treat SSTIs. Spherical and stable silver nanoparticles (AgNPs) of 14 ± 2 nm were synthesized from the aqueous extract of A. australe and silver nitrate. The antimicrobial activity against main species causing SSTIs and cytotoxicity on peripheral blood mononuclear cells of AgNP solution and its synthesis components were evaluated. Compared to its synthesis components, AgNP solution showed greater antimicrobial activity and lower cytotoxicity. The antimicrobial activity of AgNPs was due to the silver and not to the metabolites of the aqueous extract present on the surface of the nanoparticles. The plant extract played an important role in the formation of stable AgNPs and acted as a modulator of cytotoxic and immune responses.

Biosynthesis Microwave-Assisted of Zinc Oxide Nanoparticles with Ziziphus jujuba Leaves Extract: Characterization and Photocatalytic Application

The present work is intended to biosynthesize zinc oxide nanoparticles (ZnO NPs) via facile and modern route using aqueous Ziziphus jujuba leaves extract assisted by microwave and explore their photocatalytic degradation of methyl orange anionic dye and methylene blue cationic dye under solar irradiation. The biosynthesized microwave assisted ZnO NPs were characterized and the results showed that ZnO NPs contain hexagonal wurtzite and characterized with a well-defined spherical-like shape with an outstanding band gap (2.70 eV), average particle size of 25 nm and specific surface area of 11.4 m2/g. The photocatalytic degradation of the MO and MB dyes by biosynthesized ZnO NPs under solar irradiation was studied and the results revealed the selective nature of the ZnO NPs for the adsorption and further photocatalytic degradation of the MO dye compared to the MB dye. In addition, the photocatalytic degradation of MO and MB dyes by the ZnO NPs under solar radiation was fitted by the first-order kinetics. Moreover, the photodegradation mechanism proposed that superoxide ions and hydroxyl radicals are the main reactive species.

Colloidal stability of phytosynthesised gold nanoparticles and their catalytic effects for nerve agent degradation

Herein, Tilia sp. bract leachate was used as the reducing agent for Au nanoparticles (Au NPs) phytosynthesis. The colloidal properties of the prepared Au NPs were determined to confirm their stability over time, and the NPs were then used as active catalysts in soman nerve agent degradation. The Au NPs characterisation, reproducibility and stability studies were performed under transmission electron microscopy, ultraviolet visible spectroscopy and with ζ-potential measurements. The reaction kinetics was detected by gas chromatography coupled with mass spectrometry detector and solid-phase micro-extraction to confirm the Au NPs applicability in soman hydrolysis. The 'green' phytosynthetic formation of colloidal crystalline Au NPs with dominant quasi-spherical shape and 55 ± 10 nm diameter was successfully achieved, and there were no significant differences in morphology, ζ-potential or absorbance values observed during the 5-week period. This verified the prepared colloids' long-term stability. The soman nerve agent was degraded to non-toxic substances within 24 h, with 0.2156 h^-1 reaction rate constant. These results confirmed bio-nanotechnology's great potential in preparation of stable and functional nanocatalysts for degradation of hazardous substances, including chemical warfare agents.

Green synthesis of silver nanoparticles using plant extracts and their antimicrobial activities: a review of recent literature

Synthesis of metal nanoparticles using plant extracts is one of the most simple, convenient, economical, and environmentally friendly methods that mitigate the involvement of toxic chemicals. Hence, in recent years, several eco-friendly processes for the rapid synthesis of silver nanoparticles have been reported using aqueous extracts of plant parts such as the leaf, bark, roots, etc. This review summarizes and elaborates the new findings in this research domain of the green synthesis of silver nanoparticles (AgNPs) using different plant extracts and their potential applications as antimicrobial agents covering the literature since 2015. While highlighting the recently used different plants for the synthesis of highly efficient antimicrobial green AgNPs, we aim to provide a systematic in-depth discussion on the possible influence of the phytochemicals and their concentrations in the plants extracts, extraction solvent, and extraction temperature, as well as reaction temperature, pH, reaction time, and concentration of precursor on the size, shape and stability of the produced AgNPs. Exhaustive details of the plausible mechanism of the interaction of AgNPs with the cell wall of microbes, leading to cell death, and high antimicrobial activities have also been elaborated. The shape and size-dependent antimicrobial activities of the biogenic AgNPs and the enhanced antimicrobial activities by synergetic interaction of AgNPs with known commercial antibiotic drugs have also been comprehensively detailed.

Phytosynthesis of Silver Nanoparticles Using Perilla frutescens Leaf Extract: Characterization and Evaluation of Antibacterial, Antioxidant, and Anticancer Activities

Purpose

The present study investigates the phytosynthesis of silver nanoparticles (AgNPs) using Perilla frutescens leaf extract, which acts as a reducing agent for the conversion of silver ions (Ag+) into AgNPs. P. frutescens leaf synthesized AgNPs (PF@AgNPs) were evaluated for biomedical properties including antibacterial, antioxidant and anticancer activities.

Materials and Methods

PF@AgNPs were synthesized using P. frutescens leaf extract and silver nitrate solution. The morphology and physical properties of PF@AgNPs were studied by spectroscopic techniques including, UV-Vis, FTIR, TEM, XRD, DLS, and TGA. Antibacterial activity of PF@AgNPs was evaluated by disk diffusion assay. Antioxidant activity of PF@AgNPs was checked by 2.2-diphenyl-1-picrylhydrazyl (DPPH), and 2.2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radical scavenging assays. Anticancer activity of PF@AgNPs was checked by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. Cytotoxic effects of PF@AgNPs on most susceptible cancer cell lines were observed by phase contrast microscopy.

Results

PF@AgNPs showed surface plasmon resonance peak at 461 nm. XRD pattern showed that the PF@AgNPs were face-centered cubic crystals with a mean size of 25.71 nm. TEM analysis revealed the different shapes (spherical, rhombic, triangle, and rod) of PF@AgNPs. Zeta potential value (-25.83 mV) indicated that PF@AgNPs were long-term stable and not agglomerated. A low polydispersity index value (0.389) indicated the monodispersity of PF@AgNPs. TGA revealed the high thermal stability of PF@AgNPs. PF@AgNPs exhibited maximum inhibition against Escherichia coli, followed by Bacillus subtilis and Staphylococcus aureus. PF@AgNPs showed maximum inhibition of 68.02 and 62.93% against DPPH and ABTS-free radicals, respectively. PF@AgNPs showed significant anticancer activity against human colon cancer (COLO205) and prostate adenocarcinoma (LNCaP). PF@AgNPs exhibited apoptotic effects on LNCaP cells including cell shrinkage, membrane blebbing, chromatin condensation, fragmentation of nuclei, and formation of apoptotic bodies.

Conclusion

The present study reports the successful synthesis of PF@AgNPs using P. frutescens leaf extract. The synthesized PF@AgNPs are FCC crystals, monodispersed, long-term stable, and non-agglomerated. The observed antibacterial, antioxidant, and anticancer activities demonstrate the potential biomedical applications of PF@AgNPs.

Central Composite Design for Optimizing the Biosynthesis of Silver Nanoparticles using Plantago major Extract and Investigating Antibacterial, Antifungal and Antioxidant Activity

Central composite design (CCD) was applied to optimize the synthesis condition of silver nanoparticles (AgNPs) using the extract of Plantago major (P. major) seeds via a low cost and single-step process. The aqueous seed extract was applied as both reducing element and capping reagent for green production of AgNPs. Five empirical factors of synthesis including temperature (Temp), pH, volume of P. major extract (Vex), volume of AgNO3 solution (VAg) and synthesis time were used as independent variables of model and peak intensity of Surface Plasmon Resonance (SPR) originated from NPs as the dependent variable. The predicted optimal conditions was determined to be: Temp = 55 °C, pH = 9.9,Vex = 1.5 mL, VAg = 30 mL, time = 60 min. The characterization of the prepared AgNPs at these optimum conditions was conducted by Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), transmission electron microscopy (TEM) and X-ray diffraction (XRD) to determine the surface bio-functionalities. Bio-activity of these AgNPs against bacteria and fungi were evaluated based on its assay against Micrococcus luteus, Escherichia coli and Penicillium digitatum. Furthermore, antioxidant capacity of these NPs was checked using the ferric reducing antioxidant power (FRAP) assay.

Green synthesis of silver nanoparticles from Alpinia officinarum mitigates cisplatin-induced nephrotoxicity via down-regulating apoptotic pathway in rats

The rhizome of A. officinarum possesses immense pharmaceutical properties like antioxidant, anti-inflammatory, antiapoptotic, anticancer activities. The foremost downside of herbal-based drugs is their poor bioavailability, to trounce this we synthesized a herbal based silver nanodrug with Alpinia officinarum rhizome extract and assessed its effect against the cisplatin-induced nephrotoxicity in in vivo model. The A. officinarum biosynthesized silver nanoparticles (AG-AO) were characterized using UV-Spec, FTIR, XRD, TEM and SAED analysis. The antioxidant and the nephroprotective property of biosynthesized AG-AO nanoparticles were assessed by estimating the levels of kidney biomarkers, cytokine, inflammatory markers, free radicals and antioxidants induced in control and experimental. Antiapoptotic effect of AG-AO nanoparticles were evaluated by measuring the levels of apoptotic proteins in control and experimental rats. Further, it is confirmed with histopathological analysis of kidney tissue with haematoxylin and eosin staining. Our physical analysis confirms the biosynthesized silver nanoparticles by A. officinarum and it satisfies the qualities of potent nanoparticles to be used for medication. Our biochemical, molecular and histopathological results confirm the antioxidant, antiapoptotic, anti-inflammatory properties of AG-AO. Overall our results authentically confirm AG-AO is a potent nephroprotective drug, which can be a supplementary drug to prevent cisplatin-induced nephrotoxicity.

Phyto-Nanocatalysts: Green Synthesis, Characterization, and Applications

Catalysis represents the cornerstone of chemistry, since catalytic processes are ubiquitous in almost all chemical processes developed for obtaining consumer goods. Nanocatalysis represents nowadays an innovative approach to obtain better properties for the catalysts: stable activity, good selectivity, easy to recover, and the possibility to be reused. Over the last few years, for the obtaining of new catalysts, classical methods—based on potential hazardous reagents—have been replaced with new methods emerged by replacing those reagents with plant extracts obtained in different conditions. Due to being diversified in morphology and chemical composition, these materials have different properties and applications, representing a promising area of research. In this context, the present review focuses on the metallic nanocatalysts’ importance, different methods of synthesis with emphasis to the natural compounds used as support, characterization techniques, parameters involved in tailoring the composition, size and shape of nanoparticles and applications in catalysis. This review presents some examples of green nanocatalysts, grouped considering their nature (mono- and bi-metallic nanoparticles, metallic oxides, sulfides, chlorides, and other complex catalysts).

Metal nanoparticles fabricated by green chemistry using natural extracts: biosynthesis, mechanisms, and applications

Nanoparticles (NPs) are new inspiring clinical targets that have emerged from persistent efforts with unique properties and diverse applications. However, the main methods currently utilized in their production are not environmentally friendly. With the aim of promoting a green approach for the synthesis of NPs, this review describes eco-friendly methods for the preparation of biogenic NPs and the known mechanisms for their biosynthesis. Natural plant extracts contain many different secondary metabolites and biomolecules, including flavonoids, alkaloids, terpenoids, phenolic compounds and enzymes. Secondary metabolites can enable the reduction of metal ions to NPs in eco-friendly one-step synthetic processes. Moreover, the green synthesis of NPs using plant extracts often obviates the need for stabilizing and capping agents and yields biologically active shape- and size-dependent products. Herein, we review the formation of metallic NPs induced by natural extracts and list the plant extracts used in the synthesis of NPs. In addition, the use of bacterial and fungal extracts in the synthesis of NPs is highlighted, and the parameters that influence the rate of particle production, size, and morphology are discussed. Finally, the importance and uniqueness of NP-based products are illustrated, and their commercial applications in various fields are briefly featured.

Silver and gold nanoparticles biosynthesized by aqueous extract of burdock root, Arctium lappa as antimicrobial agent and catalyst for degradation of pollutants

This study presents an efficient and facile method for biosynthesis of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) using aqueous extract of burdock root (BR), A. lappa, and their applications. The nanoparticles were characterized by ultraviolet-visible spectrophotometry, X-ray diffraction, transmission electron microscopy, energy dispersive X-ray, thermogravimetry, and differential thermal analysis. AgNPs capped the BR extract (BR-AgNPs) possessed roughly spherical geometry with an average diameter of 21.3 nm while uneven geometry of AuNPs capped the BR extract (BR-AuNPs) showed multi shapes in average size of 24.7 nm. The BR-AgNPs strongly inhibited five tested microorganism strains. In particular, the nanoparticles showed excellent catalytic activity for the conversion of pollutants within wastewater. Pseudo-first-order rate constants for the degradation of 4-nitrophenol, methyl orange, and rhodamine B were respectively found 6.77 × 10^-3, 3.70 × 10^-3, and 6.07 × 10^-3 s^-1 for BR-AgNPs and 6.87 × 10^-3, 6.07 × 10^-3, and 7.07 × 10^-3 s^-1 for BR-AuNPs. Graphical abstract ᅟ.

Biogenic synthesis of AgNPs using Artemisia oliveriana extract and their biological activities for an effective treatment of lung cancer

Silver nanoparticles (AgNPs) were synthesized using Artemisia oliveriana extract, and their physicochemical characteristics were studied. The antioxidant and antimicrobial activities of the AgNPs, as well as their anticancer effects on the lung cancer cell line (A549), using 1,1-diphenyl-2-picrylhydrazyl (DPPH), MIC and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) techniques respectively demonstrated that the synthesized AgNPs mainly affected the gram-positive bacteria rather than the gram-negative bacteria, and exhibited significant cellular toxicity on the A549 cell line. Further, the cellular uptake of the AgNPs results indicated that the AgNPs accumulated within the cell. Moreover, their impact on the expression of apoptotic genes including Bax, Bcl-2, caspase-3 (CASP3), caspase-9 (CASP9) and miR-192 using real-time PCR demonstrated substantial increase in the expression of all mentioned genes (p<.001). Finally, the apoptotic effects of the AgNPs through DNA fragmentation test, flow cytometry and cell cycle analysis indicated the induction of apoptosis in the A549 cell line. The results revealed that the AgNPs synthesized using A. oliveriana extract have potential biological applications.

From biotechnology principles to functional and low-cost metallic bionanocatalysts

Chemical, physical and mechanical methods of nanomaterial preparation are still regarded as mainstream methods, and the scientific community continues to search for new ways of nanomaterial preparation. The major objective of this review is to highlight the advantages of using green chemistry and bionanotechnology in the preparation of functional low-cost catalysts. Bionanotechnology employs biological principles and processes connected with bio-phase participation in both design and development of nano-structures and nano-materials, and the biosynthesis of metallic nanoparticles is becoming even more popular due to; (i) economic and ecologic effectiveness, (ii) simple one-step nanoparticle formation, stabilisation and biomass support and (iii) the possibility of bio-waste valorisation. Although it is quite difficult to determine the precise mechanisms in particular biosynthesis and research is performed with some risk in all trial and error experiments, there is also the incentive of understanding the exact mechanisms involved. This enables further optimisation of bionanoparticle preparation and increases their application potential. Moreover, it is very important in bionanotechnological procedures to ensure repeatability of the methods related to the recognised reaction mechanisms. This review, therefore, summarises the current state of nanoparticle biosynthesis. It then demonstrates the application of biosynthesised metallic nanoparticles in heterogeneous catalysis by identifying the many examples where bionanocatalysts have been successfully applied in model reactions. These describe the degradation of organic dyes, the reduction of aromatic nitro compounds, dehalogenation of chlorinated aromatic compounds, reduction of Cr(VI) and the synthesis of important commercial chemicals. To ensure sustainability, it is important to focus on nanomaterials that are capable of maintaining the important green chemistry principles directly from design inception to ultimate application.

Physiochemical properties of Trichoderma longibrachiatum DSMZ 16517-synthesized silver nanoparticles for the mitigation of halotolerant sulphate-reducing bacteria

AIMS

In order to efficiently control the corrosive sulphate-reducing bacteria (SRB), the main precursor of the microbial influenced corrosion (MIC) in oil industry, the ability of Trichoderma longibrachiatumDSMZ 16517 to synthesize silver nanoparticles (AgNPs) was investigated and their biocidal activity against halotolerant SRB was tested.

METHODS AND RESULTS

The mycelial cell-free filtrate (MCFF) bioreduced the silver ions (Ag⁺ ) to their metallic nanoparticle state (Ag⁰ ), which was presumptively indicated by the appearance of a dark brown suspension and confirmed by the characteristic absorbance of AgNPs at ʎ_422nm . One-factor-at-a-time technique was used to optimize the effect of temperature, time, pH, fungal biomass and silver nitrate concentrations, stirring rates and dark effect. The dynamic light scattering (DLS) analysis revealed average AgNPs size and zeta potential values of 17·75 nm and -26·8 mV, respectively, indicating the stability of the prepared AgNPs. The X-ray diffraction (XRD) pattern assured the crystallinity of the mycosynthesized AgNPs, with an average size of 61 nm. The field emission scanning electron microscope (FESEM) and high-resolution transmission electron microscope (HRTEM) showed nonagglomerated spherical, triangular and cuboid AgNPs ranging from 5 to 11 ± 0·5 nm. The Fourier transform infrared spectroscopy (FT-IR) analysis of the mycosynthesized AgNPs affirmed the role of MCFF as a reducing and capping agent. A preliminary suggested mechanism for mycosynthesis of AgNPs was elucidated. The mycosynthesized AgNPs expressed high biocidal activity against a halotolerant planktonic mixed culture of SRB. The HRTEM analysis showed a clear evidence of an alteration in cell morphology, a disruption of SRB cell membranes, a lysis in cell wall and a cytoplasmic extraction after treatment with AgNPs. This confirmed the bactericidal effect of the mycosynthesized AgNPs.

CONCLUSION

The biocidal activity of the mycosynthesized AgNPs against halotolerant planktonic SRB makes it an attractive option to control MIC in the petroleum industry.

SIGNIFICANCE AND IMPACT OF THE STUDY

This research provides a helpful insight into the development of a new mycosynthesized biocidal agent against the corrosive sulphate-reducing bacteria.