Green Synthesis of nanoparticles

Objectives: In the present study we report a simple, eco-friendly and cost effective method for synthesis of silver nanoparticles (SNPs) from Adansonia digitata leaf extract and perform to know the antimicrobial potency on 07 bacterial and 05 fungal pathogens. Materials and Method: These green synthesized nanoparticles are characterized by UV-VIS spectroscopy, FTIR, XRD, AFM, SEM, TEM and to know the antimicrobial potency of nanoparticles by disc diffusion method. Results and Discussion: A broad peak obtained at 431 nm of UV-VIS spectroscopic analysis confirms the synthesized nanoparticles are silver. Phenols and proteins of leaf extract is main responsible for reduction and stabilization of these nanoparticles confirmed by FTIR. XRD pattern of synthesized nanoparticles confirms the particles are crystalline in nature and owing 44 nm in size. EDAX analysis shows 34.22 weight percentage of Ag material in the reaction medium indicates purity of sample. High resolution microscopic studies with AFM, SEM and TEM analysis reveals the nanoparticles are polydispersed in condition, spherical in shape, having the size range from 5 to 64 nm without any agglomeration. Further, the antimicrobial studies confirm the nanoparticles having broad range of antimicrobial efficacy against clinically isolated pathogenic microorganisms. Conclusions: SNPs synthesized by using Adansonia digitata leaf extract acts as effective reducing agent for production of narrow range size of SNPs. This method provides pave a way for green, cost effective and eco-friendly method for production of SNPs and can be used as effective antimicrobial agents on clinically isolated microbial pathogens.

The aim of the study was to synthesize silver nanoparticles by using aqueous extract of Coleus amboinicus lour. For the synthesis of silver nanoparticles, 50 ml extract filtrate was mixed with equal volume of 1mM silver nitrate [AgNO3 (1 mM)] and agitated at room temperature in dark. The synthesis of silver nanoparticles was investigated by UV-Vis spectroscopy, X-ray diffraction, and scanning electron microscopy (SEM) with Energy dispersive X-ray (EDX). Results indicate the synthesis of silver nanoparticles in the reaction mixture. Obtained silver nanoparticle showed the antioxidant activity and cytotoxicity against the Ehrlich’s ascite carcinoma (EAC) cell line.

Developing a rapid, reliable and eco-accommodating methodology for the synthesis of metal/metal oxide nanoparticles (NPs) is an important step in the area of nanotechnology. Cobalt oxide nanoparticles (Co3O4 NPs) have been widely studied due to their potential applications including, antibacterial, antifungal, electrochromic sensors, heterogeneous catalysis, and energy storage devices. Due to the large rate of perilous chemicals employed in the physical and chemical production of these NPs, green methods employing the use of plants, fungus, algae, and bacteria have been adopted. However, plant-mediated synthesis of metal NPs has been developed as a substitute to defeat the restrictions of conventional synthesis approaches such as physical and chemical methods. Biomolecules, such as tannins, saponins, proteins, amino acids, steroids, enzymes, flavonoids, and vitamins from several plant extracts have been used as a stabilizing and reducing agents for the synthesis of Co3O4 NPs. Recently, several attempts were made to develop plant-mediated synthesis methods to produce stable, cost-effective, and eco-accommodating Co3O4 NPs. In this review, a comprehensive study was conducted on synthesis, characterization, and various applications of Co3O4 NPs produced using various plant sources.

L-Cysteine stabilised semiconductor CdSe nanoparticles were synthesised in aqueous medium by simple greener wet chemical method at room temperature from CdCl 2 .21/2H 2 O and Na 2 SeO 3 .5H 2 O and elemental selenium precursors for a short duration. The synthesised CdSe nanoparticles were characterised by powder X-ray diffraction (XRD), Fourier transform infrared (FTIR), UV-visible, transmission electron microscopy (TEM) and selected area electron diffraction (SAED) techniques. The powder XRD pattern and SAED pattern were in good agreement with each other and conform to the formation of single-phase CdSe nanoparticles. The FTIR studies reveal the capping effect of L-Cysteine in the formation of CdSe nanoparticles. The absorption maxima in UV-visible spectra clearly indicate the size quantisation effect and TEM image reveals that the size of the CdSe is about 10 nm.

Cerium oxide (CeO 2) and 1%, 5% and 10% tin-doped CeO 2 nanoparticles (Sn-doped CeO 2 NPs) were synthesized using aqueous leaf extracts of Pometia pinnata. UV-Vis diffuse reflectance spectroscopy showed band gap energies of 2.47-2.66 eV. X-ray diffraction results confirmed the formation of a fluorite phase of CeO 2 and Sn-doped CeO 2 NPs with average crystallite sizes between 6 and 19 nm. X-ray photoelectron spectroscopy (XPS) analysis further established the synthesis of CeO 2 and Sn-doped CeO 2 NPs. The density of states was proposed accordingly using the valence band-XPS data. Scanning electron microscopic and transmission electron microscopic studies showed almost spherical shaped particles with average particle sizes around 15-20 nm. All synthesized nanomaterials were tested for photoantioxidant activity under visible light and in the dark and showed improved photoantioxidant activity under visible light irradiation for dose and time-dependent studies. The synthesized nanomaterials were also tested for antibiofilm activities and exhibited significant concentration-dependent antibiofilm activity against Gram-positive pathogenic bacteria such as Staphylococcus aureus and Listeria monocytogenes. The 10% Sn-doped CeO 2 NPs and S-CeO 2 NPs also exhibited bactericidal activity against Staphylococcus aureus. These studies showed that S-CeO 2 and Sn-doped CeO 2 NPs have both good antioxidant and antibacterial properties.

Silver nanoparticles were successfully synthesized using crude neem leaf (Azadirachta indica) extract at room temperature. The formation and crystallinity of synthesized silver nanoparticles was confirmed by X-Ray diffraction (XRD) pattern. The average size of these silver nanoparticles is about 20-50 nm as observed by Transmission electron microscopy (TEM) images. Optical absorption measurements were performed to determine band-edge energy gap of these silver nanoparticles. Photoluminescence (PL) studies were performed to emphasize its emission properties. The synthesized silver nanoparticles could have major applications in the area of nanoscale optoelectronics devices and biomedical engineering. Our synthesis method has advantage over other conventional chemical routes because it is cost effective & environmental compatibility.

We present the synthesis and antibacterial
activity of silver nanoparticles using Caulerpa racemosa, a
marine algae. Fresh C. racemosa was collected from the
Gulf of Mannar, Southeast coast of India. The seaweed
extract was used for the synthesis of AgNO3 at room
temperature. UV–visible spectrometry study revealed surface
plasmon resonance at 413 nm. The characterization of
silver nanoparticle was carried out using Fourier transform
infrared spectroscopy (FT-IR), X-ray diffraction (XRD)
and transmission electron microscope (TEM). FT-IR
measurements revealed the possible functional groups
responsible for reduction and stabilization of the nanoparticles.
X-ray diffraction analysis showed that the particles
were crystalline in nature with face-centered cubic geometry.
TEM micrograph has shown the formation of silver
nanoparticles with the size in the range of 5–25 nm. The
synthesized AgNPs have shown the best antibacterial
activity against human pathogens such as Staphylococcus
aureus and Proteus mirabilis. The above eco-friendly
synthesis procedure of AgNPs could be easily scaled up in
future for the industrial and therapeutic needs.

The development of nanotechnology is making the interest of researchers towards the synthesis of nanoparticles for bioapplication. In recent years, metal oxides such as ZnO have received increasing attention as antibacterial materials because of their stability under harsh processing conditions. They are generally regarded as safe materials for human beings and animals. Zinc activates  300 enzymes, and it plays a role in many other phenomena like growth,  membrane stability, bone mineralization, tissue growth and repair, wound healing and cell signalling. Many studies have shown that ZnO nanoparticles have enhanced antibacterial activity. The use of plant and plant materials to synthesise Zinc nanoparticles is a relatively new and exciting research field.  Various plants were used for the synthesis of nanoparticles using the green synthesis method.  Nanoparticles were synthesized from all the plant parts separately like stem,  flower,  leaf, latex, root,  peel, stem bark and fruits.  The prepared Zinc oxide nanoparticles were characterized by using  XRD,  FTIR,  UV-VIS Spectroscopy,  EDAX,  Particle size analyzer, TGA, and  SEM. The objective of this review was to report on the synthesis of Zinc oxide nanoparticles by using different plant extracts and their significance in different fields.

Narrow band gap zinc oxide (ZnO) nanoparticles (NPs) were synthesized using unboiled and boiled leaf extracts of Costus woodsonii. The as-synthesized NPs were characterized using a range of techniques. The as-synthesized ZnO NPs were crystalline with a hexagonal wurtzite structure similar to the commercial ZnO (ZnO-C). The maximum absorbance was observed at ~390 nm for ZnO-C and the as-synthesized ZnO NPs (ZnO-UL and ZnOBL) showed a red shift, i.e. ~448 nm to ~462 nm, hence, a lower band gap of ~2.68–2.77 eV. The band gap energy of the as-synthesized ZnO NPs was lower than that of commercial ZnO. The surface of ZnO was coated/modified with the components of the leaf extract. The as-synthesized ZnO NPs showed similar particle sizes and were spherical in shape. These studies confirmed the green synthesis of ZnO NPs using Costus woodsonii and the significantly reduced band gap (Eg =~2.68 eV to ~2.77 eV) of the as-synthesized ZnO NPs compared to the ZnO-C (Eg =3.18 eV).

Silver nanoparticles were successfully synthesized from AgNO 3 through a simple green route using the latex of Jatropha curcas as reducing as well as capping agent. Nanoparticles were characterized with the help of HRTEM, X-ray diffraction and UV-vis absorption spectroscopy. X-ray diffraction analysis showed that the nanoparticles were of face centered cubic structure. A comparison of radius of nanoparticles obtained from HRTEM image with the optimized cavity radius of the cyclic peptides present within the latex revealed that the particles having radius 10-20 nm are mostly stabilized by the cyclic peptides.

Among diverse non-metal nanoparticles (NPs), sulfur nanoparticles (SNPs) are one of the most significant and intriguing nanomaterials. An important concern about the synthesis of SNPs is the formation of hazardous wastes, noxious by-products and ruinous pollutants. The best solution to mitigate and/or exclude these noxious substances are plant mediated biosynthesis of SNPs. Eco-benevolent SNPs from plant extracts have been identified as precious nanomaterial in various agricultural, biomedical and catalytic applications including lithium-sulfur batteries, pesticides, fungicides, carbon nanotube modification, gas sensor and neutron capture in cancer therapy because of their splendid performance and selectivity. They have captured the consideration of researchers owing to their sustainable, economical, non-noxious, convenient, green and eco-benevolent nature. This review attempts to cover the recent advancements in the biosynthesis, characterization techniques and applications of biogenic SNPs in environmental and biomedical systems. Furthermore, the stability of biosynthesized SNPs and mechanism of their formation are briefly discussed.

The present study reports the synthesis and characterization of ZnO nanoparticles by green synthesis method. The capping agent of Ocimum tnuiflorum leaf extract was used as a reducing agent in the preparation of ZnO nanoparticles. The synthesized ZnO nanoparticles were characterized by X-Ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), scanning electron microscope (SEM) and Energy Dispersive Analysis of X−rays (EDAX). The obtained results reveal that the crystalline size, morphology and composition match well with the standard values and will be useful for antibacterial applications.

The synthesis of nanoparticles has become the matter of great interest in recent times due to its various advantageous properties and applications in various fields. Though physical and chemical methods are more popular for nanoparticles (NPs) synthesis and the biosynthesis (green method) of nanoparticles using plant extracts is a better option due to its eco-friendliness. In this paper, we report the synthesis of CaCO 3 (Calcite) nanoparticles using CaCl 2 and selected plant species of Boswellia ovalifoliolata (an endemic plant) as the reducing agent. After exposing CaCl 2 to bark extract of plant, the nanoparticles are appeared in the form of precipitate. These are characterized by using Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray (EDAX) and Fourier Transform Infrared Spectroscopy (FTIR). The analysis of SEM information shows that the formation of stable nanoparticles are mostly spherical in shape with a diameter ranging from 40 to 75 nm and FTIR data revels that the plant extract containing phenolic compounds and proteins are act as reducing agents and the biologically synthesized NPs are calcite type of calcium carbonate nanoparticles (CCNP's). To observe the effect of CCNP's on seed germination and seedling growth of Vigna mungo shows that the bio-synthesized CCNPs accelerate the seed germination and seedling growth in V. mungo and shows the highest percentage of Seed germination, Seedling vigor index, Root and Shoot length, Fresh and Dry weight and Relative water content.

Nanotechnology is a rapidly developing field because of its wide range of applications in science, nanoscience and biotechnology. Nanobiotechnology deals with nanomaterials synthesised or modified using biotechnology. Fungi are used to synthesise metal nanoparticles and they have vast applications in wound healing, pathogen detection and control, food preservation, textiles, fabrics, etc. The present review describes the different types of fungi used for the biosyntheses of silver nanoparticles (AgNPs), along with their characterisation and possible biological applications. AgNPs synthesised by other physical and chemical methods are expensive and have toxic substances adsorbed onto them. Therefore, green, simple and effective approaches have been chosen for the biosynthesis of AgNPs, which are very important because of their lower toxicity and environmentally friendly behaviour. AgNPs synthesised using fungi have high monodispersity, specific composition and a narrow size range. In this regard, among the different biological methods used for metal nanoparticle synthesis, fungi are considered to be a superior biogenic method owing to their diversity and better size control. To further understand the biosynthesis of AgNPs using various fungi and evaluate their potential applications, this review discusses the antimicrobial, antibacterial, antifungal, antiviral, antidermatophytic, anti-inflammatory, antitumor, hepatoprotective, cytotoxic, hypotensive, and immunomodulatory activities of these AgNPs. The synthesis of AgNPs using fungi is a clean, green, inexpensive, eco-friendly, reliable, and safe method that can be used for a range of applications in real life for the benefit of human beings.

Silver nanoparticles (Ag NPs) have gained huge attention and popularity in the scientific world due to their intriguing physical, chemical and antimicrobial properties. Ag NPs can be synthesized by physical, chemical and biological processes. Since there is pressing need for eco-friendly, and sustainable synthetic method, extensive research is taking place about the green synthesis of Ag NPs using plants. Biosynthesized Ag NPs show excellent biocompatibility and antibacterial property and hence have wide applications in agriculture and other fields. In view of this, we have reviewed here the use of plants or their extracts for the synthesis of Ag NPs, their characterization, and effect of physicochemical parameters on the synthesis. This review underlines the applications of biosynthesized Ag NPs in the agriculture sector with a short note on its future prospects.

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)] nanoparti-cles 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.

Towards the future of green, sustainable and renewable products the suggestion of using the agriculture biomass in the coming decades got increased. Biomass material is one of the important sources of alternative material for the production of biocomposite products. An increasing global awareness about environmental issues is acting as the driving force behind the utilization of biomass material as valuable products. Bio-waste materials (agricultural waste) have been recognized as an ecological burden for the society they stimulated new gateways for the production of renewable, low cost and sustainable adsorbents for water treatment applications. In the area of water purification, nanotechnology offers the possibility of an efficient removal of pollutants and bacteria. Adsorption has proved that it is the best process of water treatment technologies, because of its significant advantages. Different modification methods of waste-based adsorbents, have also been presented to highlight and discuss the key advancements on the preparation of novel adsorbents using agricultural " agro-waste ". Adsorption mechanisms responsible for pollutants removal by waste-based adsorbents have also been discussed. It also focuses on the computational aspects of binding of biomolecules to nanoparticles (NPs) and some of the applications of the biosynthesized NPs as water purification. The nature acts like a large ''bio-laboratory " comprising of plants, algae, fungi, yeast, etc. which are composed of biomolecules. These naturally occurring biomolecules have been identified to play an active role in the formation of nanoparticles with distinct shapes and sizes thereby acting as a driving force for the designing of greener, safe and environmentally benign protocols for the synthesis of NPs. The biosynthesis of NPs using waste materials will help researchers not only to design safer nanomaterials but also to promote the understanding of health and safety considerations of NPs. Useful materials can be produced easily even at reasonable scale because the biomaterial based routes eliminate the need to use toxic chemicals. The aim of this review is to summarize the adsorption capacities for organic and inorganic pollutants by different bio-waste-based adsorbents.

A B S T R A C T Voltammetric methods for screening compounds of varied interests are reviewed on the basis of the types of electrodes and analytical strategies. The scope of conventional voltammetric method has been considerably expanded in the last years due to the development of a plethora of modified electrodes, in particular, those involving nanocomposites. Voltammetric methods have distinct advantages over other existing methods regarding sensitivity, minimum detectability, applicability to biological samples without any pretreatment and time saving. Simultaneous determination of compounds by voltammetry offers the advantages of being economical and less time consuming as more than one analyte can be detected easily on the fabricated sensor at the same time. Present review article focuses on the simultaneous voltammetric detection of various compounds reported during the last five years.

Since its advent, nanotechnology has become an indispensable area of research and innovation, introducing revolutionary changes in current research areas like engineering, medical sciences, drug discovery and formulations, optoelectronics and biosensors. Metallic nanoparticle synthesis has become a requisite of modern experimentation however, much of the research involves either silver or gold nanoparticles. Considering the fact, it is imperative to explore the potentials of other metallic nanoparticles as well. Current review focuses on exploration of potentials of Copper nanoparticles in various domains of research. The review highlights common synthesis methods of Copper nanoparticle synthesis and the superiority of green route over other approaches. Characterization techniques and multifarious biological potentials of Copper nanoparticles have also been reviewed. Researchers have recognized green synthesis route as the best alternative to traditional methods utilized for synthesizing copper nanoparticles. Green synthesized Copper nanoparticles have also been found to have superior antioxidant, antimicrobial, antifungal, cytotoxic and photocatalytic potentials. As of now, the exact mechanism behind synthesis and biological activities of Copper nanoparticles is not known. Identification of the exact mechanism can revolutionaries the discipline of nanotechnology.

Cerium oxide nanoparticles (CeO2 NPs) are a sought-after material in numerous fields due to their potential applications such as in catalysis, cancer therapy, photocatalytic degradation of pollutants, sensors, polishing agents. Green synthesis usually involves the production of CeO 2 assisted by organic extracts obtained from plants, leaves, flowers, bacteria, algae, food, fruits, etc. The phytochemicals present in the organic extracts adhere to the NPs and act as reducing and/or oxidizing agents and capping agents to stabilize the NPs, modify the particle size, morphology and band gap energy of the as-synthesized materials, which would be advantageous for numerous applications. This review focuses on the green extract-mediated synthesis of CeO 2 NPs and discusses the effects on CeO 2 NPs of various synthesis methods that have been reported. Several photocatalytic, antimicrobial, antioxidant and cytotoxicity applications have been evaluated, compared and discussed. Future prospects are also suggested.

A  new  and  novel  approach  for  the  green  synthesis  of  silver
nanoparticles  is  the  need  of  the  hour.  Use  of  plant  parts  for  the
synthesis of silver nanoparticles is ecofriendly, economic and cost
effective. In the present paper, silver nanoparticles were synthesized
using  aqueous  stem  extract  of Cassia  roxburghii DC  as  a  reducing
agent.  The  biosynthesized  AgNPs  were  characterized  by  various
spectral analysis like UV–Vis, FTIR, XRD, TEM and Zeta potential
measurement. UV–vis spectra showed maxima absorption peak at
432  nm.  XRD  and  TEM  analysis  revealed  AgNPs  to  be  facecentered, cubic structures spherical in shape with an average particle
size of 32-35 nm.
The synergistic antibacterial activity was evaluated against two Gram
positive,  two  Gram  negative  bacteria  and  four  fungi  with  fifteen
commercial antibiotics alone and antibiotics plus synthesized AgNPs.
Antioxidant  activity  of  AgNPs  was  evaluated  by  ABTS  and  FRAP
assay.  The  AgNPs  showed  synergistic  antibacterial  activity  even
better than some antibiotics and also good  antioxidant activity. The
results suggest that Cassia roxburghii stem could be exploited for the
fabrication  of  AgNPs  with  potential  therapeutic  application  in
nanomedicine especially against multi drug resistant microorganisms
which  are  cost  effective  and  ecofriendly  and  simple.  They  can  be
definitely used in cosmetics, medical and pharmaceutical applications

Silver nanoparticles were synthesized in an aqueous solution of silver nitrate using Carica papaya leaf extract as the reducing agent. These nanoparticles were characterized by photoluminescence and UV-Vis spectroscopy. Fourier-transform infrared spectroscopy results showed that the nanoparticles were capped with biomoites that are responsible for efficient stabilization. XRD analysis revealed that most nanoparticles were spherical in shape with a face-centered cubic structure and crystalline grains. Moreover, Atomic Force Microscopy (AFM) showed that the grain size ranged from 7 to 32 nm, which agreed with the XRD results. The calculated zeta potential was found to be −15.58 mV, which indicated good stability. The antibacterial activity results showed that the synthesized silver nanoparticles exhibited excellent activity against Pseudomonas aeruginosa and Klebsiella pneumoniae. The molecular docking study revealed that the antiviral activity of the C. papaya leaf extract showed good binding affinity against dengue type 2 virus non-structural protein 1.

Green synthesis is a widely used for the preparation of silver nanoparticles. The use of plant extracts for these syntheses has become common in recent years because they are nontoxic, inexpensive, and widely available. Phytochemicals such as terpenoids, flavones, ketones, aldehydes, amides, and carboxylic acids are the primary active ingredients for nano-particle synthesis. Reaction temperature plays an important role during the reduction process as it influences the reaction time, particle size, and the intensity of the surface
plasmon resonance peak. This review presents an overview of recently developed and reported silver nanoparticle syntheses using plant extracts. The role of temperature in nanoparticles synthesis and potential applications has been reviewed. A brief
description of the reaction mechanism and nanoparticle characterization techniques are also included.

A critical investigation on the fabrication of metal oxide nanoparticles (NPs) such as ZnO, SnO2, and CeO2 NPs synthesized from green and phytogenic method using plants and various plant parts have been compiled. In this review, diferent plant extraction methods, synthesis methods, characterization techniques, efects of plant extract on the physical, chemical, and optical properties of green synthesized ZnO, SnO2, and CeO2 NPs also have been compiled and discussed. Efect of several parameters on the size, morphology, and optical band gap energy of metal oxide have been explored. Moreover, the role of solvents has been found important and discussed. Extract composition i.e. phytochemicals also found to afect the morphology and size of the synthesized ZnO, SnO2, and CeO2 NPs. It was found that, there is no universal extraction method that is ideal and extraction techniques is unique to the plant type, plant parts, and solvent used.

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Development of reliable and environmentally gracious routes for the fabrication of metal oxide nanoparticles is a crucial step in nano-biotechnology. Among the all zirconia nanoparticles (ZrO2 NPs) draws more attention due to its significant biocompatible, electrical, mechanical, and optical properties. Many natural biomolecules in plant extracts such as alkaloids, amino acids, enzymes, proteins, polysaccharides, polyphenols, steroid, and vitamins could be involved in bioreduction, formation, and stabilization of ZrO2 NPs. In the last decade, numerous efforts were made to develop ecofriendly methods of synthesis to avoid the hazardous byproducts. In this review, green synthesis of ZrO2 NPs, their characterization techniques, and miscellaneous applications were discussed.

Till date several methods of chemical synthesis of silver nanoparticles (AgNps) are known. Most of the protocol dealing with the chemical synthesis of AgNps involves high pressure, temperature, energy and technical skills. Thus, a method with much greener approach is the need of the hour. Accordingly, the authors have developed a method that is costeffective, energy-efficient and easy method for the synthesis of AgNps. The AgNps were synthesised by using white sugar and sodium hydroxide (NaOH) in the presence of sunlight. These nanoparticles were characterised by visual observation, ultraviolet-visible (UV-vis) spectrophotometry, Fourier transform infrared (FTIR), nanoparticle tracking and analysis (NTA) and transmission electron microscopy (TEM). The effect of NaOH on the rate of AgNps synthesis was also studied. Formation of AgNps was primarily detected by change in colour of reaction mixture from colourless to yellow after treatment with 1 mM silver salt (AgNO 3 ). UV-vis spectroscopy showed peak at 409 nm. NTA revealed the polydispersed nature of nanoparticles, 15-30 nm in diameter. FTIR showed the presence of gluconic acid as capping agent, which increases the stability of AgNps in the colloids. TEM demonstrated the presence of spherical AgNps in the range of 10-25 nm. The present method confirms the synthesis of AgNps by using white sugar and NaOH. This method is simple, eco-friendly and economically sustainable, making it amenable to large-scale industrial production of AgNps.

Nanoscale zerovalent iron (nZVI) particles represent an important material for diverse environmental applications because of their exceptional electron donating properties, which can be utilized, e.g., for reduction, catalysis, adsorption and degradation of a broad range of pollutants. The synthesis and assembly of nZVI using biological and natural sustainable resources is an attractive option for alleviating environmental contamination worldwide. In this review, various green synthesis pathways for generating nZVI particles are summarized and compared with conventional chemical and physical methods. In addition to describing the latest environmentally benign methods for the synthesis of nZVI, their properties and interactions with diverse biomolecules are discussed, especially in the context of environmental remediation and catalysis. Future prospects in the field are also considered.

El uso de las nanopartículas (NPs) de oro se remonta al el siglo IV d.C, en la copa de Licurgo fabricada artesanalmente por los romanos. El proceso para la síntesis de NPs no era sencillo de estandarizar, hasta que Turkevich en 1953 estableció los criterios que deben seguirse para tener mayor control de la morfología y tamaño de NPs obtenidas (en su caso cuasi-esferas de ∼15nm de diámetro). La desventaja de su método es que genera residuos tóxicos al medio ambiente. Por ello una vertiente actual de investigación consiste en la búsqueda de métodos verdes de síntesis mediante compuestos capaces de efectuar la misma labor que los reactivos químicos con cierta toxicidad, pero que sean amigables con el ambiente. Una alternativa a explorar son las algas, las cuales se componen mayormente de polisacáridos y en particular las de clase Phaeophyceae, como la Egregia menziesii que además contiene metabolitos secundarios aplicables en biomedicina. En el presente trabajo se buscó sintetizar NPs de oro usando un extracto del alga E. menziesii como reactivo reductor de un precursor de oro. También se presenta la caracterización de las muestras obtenidas, utilizando espectrofotometría UV-Visible y microscopía electrónica de transmisión (TEM). Se evaluó la estabilidad de las NPs en dispersión coloidal. Y se elaboraron histogramas de distribución del diámetro de las NPs con morfología cuasi-esférica. Se propone entonces, que el extracto de E. menziesii no solo funge como agente reductor para la síntesis de las NPs de oro, sino que además participa como agente estabilizante de las mismas. Es así que se comprobó que el extracto de E. menziesii es capaz de sintetizar NPs de oro y obtener dispersiones altamente estables con distribuciones de tamaño cuya dispersión resulta ser angosta.

The hazardous effects of current nanoparticle synthesis methods have steered researchers to focus on the development of newer environmentally friendly and green methods for synthesizing nanoparticles using nontoxic chemicals. The development of environmentally friendly methods of nanoparticle synthesis with different sizes and shapes is one of the pressing challenges for the current nanotechnology. Several novel green approaches for the synthesis of AuNPs have been explored using different natural sources, such as plants, algae, bacteria, and fungi. Among organisms, algae and blue–green algae are of particular interest for nanoparticle synthesis. Gold nanoparticles (AuNPs) have a range of applications in medicine, diagnostics, catalysis, and sensors because of their significant key roles in important fields. AuNPs have attracted a significant interest for use in a variety of applications. The widespread use of AuNPs can be accredited to a combination of optical, physical, and chemical properties as well as the miscellany of size, shape, and surface composition that has been adopted through green synthesis methods.

The hazardous effects of current nanoparticle synthesis methods have steered researchers to focus on the development of newer environmentally friendly and green methods for synthesizing nanoparticles using nontoxic chemicals. The development of environmentally friendly methods of nanoparticle synthesis with different sizes and shapes is one of the pressing challenges for the current nanotechnology. Several novel green approaches for the synthesis of AuNPs have been explored
using different natural sources, such as plants, algae, bacteria, and fungi. Among organisms, algae and blue–green algae are
of particular interest for nanoparticle synthesis. Gold nanoparticles (AuNPs) have a range of applications in medicine, diagnostics, catalysis, and sensors because of their significant key roles in important fields. AuNPs have attracted a significant interest for use in a variety of applications. The widespread use of AuNPs can be accredited to a combination of optical, physical, and chemical properties as well as the miscellany of size, shape, and surface composition that has been adopted through green synthesis methods.

Metal oxide nanoparticles (NPs) produced by green chemistry approaches have received notable attention because of their significant physico-chemical properties and their remarkable uses in the area of nanotechnology. Currently, the sustainable improvement of synthesizing NPs by distinctive parts of plant extract has become a major focus of scientists and researchers, because these NPs have a minimum detrimental effect on ecosystem and minimum noxiousness for the human health. Among the metal oxide nanoparticles, alumina nanoparticles (Al 2 O 3 NPs) draw a special attention due to their significant applications in ceramics, textiles, drug delivery, catalysis, waste-water treatment and biosensor. Many natural biomolecules in plant extracts such as saponins, tannins, alkaloids, amino acids, enzymes, proteins, coumarins, polysaccharides, polyphenols, steroid and vitamins could be participated in bioreduction and stabilization of Al 2 O 3 NPs. In the last decade, innumerable efforts were made to develop a sustainable eco-accommodating method of synthesis to avoid the perilous byproducts. This review focuses on the plants used for the green fabrication of Al 2 O 3 NPs, their characterization methods and applications.

Black peel pomegranate is one of the rarest cultivars of Punica granatum that has not been studied precisely. However, selective cytotoxicity and potent antioxidant activity of the fruit peel extract have already been revealed. This study aimed to investigate the antibacterial activity of the extract, and silver nanoparticles synthesized by the extract, against gram-positive and gram-negative bacterial strains. Nanoparticles were characterized by UV–Vis spectroscopy, FE-SEM, and EDS, and their Zeta potential was also evaluated. According to the results, the spherical nanoparticles had an average size of 19 nm and the surface charge of −33 mV. Both extract and silver nanoparticles showed potent antibacterial activity against P. aeruginosa and S. aureus strains, although the gram-negative strain (P. aeruginosa) was less sensitive to these agents. Furthermore, these nanoparticles were able to kill the bacteria at very low concentrations (MBC = 40–65 μg/ml), while no MBC for the extract was determined, confirming it is a bacteriostatic agent. The results determine that “black peel pomegranate” can be considered as a high potential agent to combat infectious diseases due to its significant bacteriostatic activity.

This research work presents a facile and green route for synthesis silver sulfide (Ag2SNPs) nanoparticles from silver nitrate (AgNO3) and sodium sulfide nonahydrate (Na2S.9H2O) in the presence of rosemary leaves aqueous extract at ambient temperature (27 oC). Structural and morphological properties of Ag2SNPs nanoparticles were analyzed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The surface Plasmon resonance for Ag2SNPs was obtained around 355 nm. Ag2SNPs was spherical in shape with an effective diameter size of 14 nm. Our novel approach represents a promising and effective method to large scale synthesis of eco-friendly antibacterial activity silver sulfide nanoparticles.

Nanotechnology is rapidly expanding research area, encompassing the development of man-made materials in nanometer size range. Nanoscale drug delivery system using various nanomaterials is emerging technology for the rational delivery of many chemotherapeutic agents. Nanoparticles attracted the scientists across many disciplines to engineer many desired properties that might otherwise be incompatible on a single device. Formulation scientists are facing the challenges such as poor solubility and bioavailability of the newly invented drugs. One of the approaches to face the above challenge is to develop the particulate carrier system. Solid lipid nanoparticle or liposphere or nanosphere system is the most feasible particulate carrier system which is an alternative to nanoemulsions, liposomes and polymeric nanoparticles. This system offers added advantages in comparison to other related particulate drug delivery systems. The present review emphasizes on various basic and applied aspects of solid lipid nanoparticles in novel drug delivery system especially techniques involved in their production, characterization and various applications. It also focuses on the drug loading capacity, drug incorporation and factors affecting drug release from this colloidal system.

Heterogeneous photocatalysis offer many possibilities for finding appropiate environmentally friendly solutions for many of the the problems affecting our society (i.e., energy issues). Researchers are still looking for novel routes to prepare solid photocatalysts able to transform solar into chemical energy more efficiently. In many developing countries, biomass is a major energy source, but currently such countries lack of the technology to sustainably obtain chemicals and/or fuels from it. The Roadmap for Biomass Technologies, authored by 26 leading experts from academia, industry, and government agencies, has predicted a gradual shift back to a carbohydrate-based economy. Biomass and biofuels appear to hold the key to satisfy the basic needs of our societies for the sustainable production of liquid fuels and high value-added chemicals without compromising the scenario of future generations. In this review, we aim to discuss various

Background: Rumex nepalensis, a widely known traditional medicinal plant and is used as the source of medicines and human diet in various communities. Currently, the phytochemical investigation and pharmacological studies of R. nepalensis are of significant research interest. Therefore, the current review is mainly focused on the phytochemical investigation and pharmacological applications of R. nepalensis Main body: Various secondary metabolites like emodin, endocrocin, chrysophanol, neopodin, physcion, torachrysone, aloesin, catechin, quercetin, resveratrol, and their derivatives were isolated from root and aerial parts of the plant. Both isolated compounds and extracts from R. nepalensis are reported to have pharmacological activities such as antiinflammatory, antioxidant, antimicrobial, wound healing, and anti-plasmodial activities Conclusions: Different parts of R. nepalensis have ethnomedicinal importance. R. nepalensis is one of the potential sources of pharmacologically active extracts and isolated compounds. In future R. nepalensis can play a vital role for the preparation of modern drugs.

Several concerns exist regarding horse rearing such as environmental pollution, antibiotics resistance, digestive disorders, mycotoxins contamination of animal feed, gut health management, and improvement of feed efficiency. Nanoparticles have the potential to address these issues and thus could be used as feed additive. Citrate reduces and stabilizes gold  anoparticles, alongside bio-synthesized silver nanoparticles have the potential to prolong and improve digestive enzyme activity, which would enhance starch digestibility in the stomach. Zinc oxide and selenium nanoparticles could be used to improve feed digestibility and volatile fatty acids production. Magnesium oxide, silver, and copper nanoparticles exhibit strong antimicrobial activity against gram-positive and gram-negative microbes
and weaken the biofilm formation of the microbial community. Calcium, zinc, and silver nanoparticles
could be used to prevent periodontal disease in horses. In addition, silver nanoparticles may be applied as antifasciolitics and potentially against other gastrointestinal parasites. Environmental concern of
equines could be addressed by using cerium oxide, silver, and cobalt nanoparticles to reduce methane emission and zinc oxide could help to reduce fecal mineral output. Fullerol C60[OH]24, a honey-derived silver nanoparticle and zinc oxide nanoparticles exhibit attractive antibacterial properties because of increased specific surface area as the reduced particle enhance unit surface reactivity. Gut health management of equines could be solved with nanoparticles because of the ability of ferrous oxide and copper nanoparticles to improve microbial growth, whereas zinc oxide improves villus height, crypt depth, and villous surface area. It is required to explore in depth the beneficial effects of these nanoparticles as a novel area in the equine industry's both in vitro and in vivo before recommendation to equine owners.

The paper presents a review of green syntheses and selective applications of bismuth vanadate nanoparticles (BiVO4 NPs). Generally, ample number of biomolecules exists in plant extracts and these are mainly accountable for the facile green synthesis of BiVO4 NPs. Moreover, BiVO4 NPs has been widely researched in chemistry, biotechnology, physics and biochemistry fields due to their interesting technological chemical, biological, ionic conductivity and ferro-elastic properties. It can also be used in diverse fields, such as sensors, photocatalysis, water splitting and antimicrobial activity. Till date, BiVO4 NPs has been synthesized by various known physical and chemical approaches. The article mainly discusses the green synthesis of BiVO4 NPs via plant extracts. Moreover, this article shows a detailed overview of the green synthesis, characterization and significant applications of BiVO4 NPs.

Green synthesis of nanoparticle is a novel way to synthesis nanoparticles using biological sources. It is gaining attention due to its cost effective, ecofriendly and large scale production possibilities. In the present study (Carissa carandas)redberryfruits were taken to investigate their potential to synthesis metal oxide nanoparticle. The ZnO, CuO, MgO nanoparticles synthesized were confirmed by their change of colour due to the phenomenon of surface Plasmon resonance. The characterization study was done by UV-Vis spectroscopy, Fourier Transmission Infrared Spectroscopy (FTIR), X-Ray diffraction (XRD), The above metal oxide nanoparticles were found to be effective against Pseudomonas, Bacillus and staphylococcus.

In the present study, we report the aqueous extract of Pithophora oedogonia to produce silver nanoparticles (AgNPs) by reduction of silver nitrate. It was noted that synthesis process was considerably rapid and silver nanoparticles were generated within few minutes of silver ions coming in contact with the algal extract. A peak at 445 nm corresponding to the plasmon absorbance of AgNPs was noted in the UV–vis spectrum of the aqueous medium that contained silver ions. Scanning electron microscopic (SEM) and dynamic light scattering analysis of colloidal AgNPs indicated the size of 34.03 nm. Energy-dispersive X-ray spectroscopy revealed strong signals in the silver region and confirmed of the AgNPs. Fourier transform infrared spectroscopic analysis of the nanoparticles indicated the presence of protein which was regarding a capping agent surrounding the AgNPs. Moreover, the antibacterial activity of synthesized nanoparticles exhibited potential inhibitory activity against seven tested pathogenic bacteria.

In this report a simple and eco-friendly biosynthesis of silver
nanoparticles using Pomegranate peel extract as the reducing agent
from 1 mM AgNO3 had been investigated. The formation of silver
nanoparticles was characterized by UV-Vis spectrum, Fourier
Transform Infrared Spectroscopy (FT-IR) and Scanning Electron
Microscopic (SEM) analysis. The UV-Vis spectra results show a
strong resonance centered on the surface of silver nanoparticles
(AgNPs) at 371 nm. The Fourier Transformation Infrared
Spectroscopy spectral study demonstrates pomegranate peel extract
acted as the reducing agent. The scanning electron microscopic
(SEM) analysis shows nanoparticles with the average particles size
ranges about 5-50 nm. Further the antibacterial activity of AgNPs
was evaluated against Staphylococcus aureus, Pseudomonas
aeruginosa and Escherichia coli pathogens. This route is rapid,
simple, without any hazardous chemicals as reducing or stabilizing
agents and economical to synthesize AgNPs.