Synthesis of Nanoparticles Using Wastewater-Isolated Bacteria and Evaluation of Their Antimicrobial Activity

Silver nanomaterials have been integrated into industrial, biomedical and agricultural application, including biosensor, anti-microbial, anti-tumor, drug delivery, waste treatment, coated fabrics and nano fertilizer. Nanoparticle possesses unusual character due to their large surface area to volume ratio and an extraordinary catalytic activity, electronic properties, optical properties and anti-microbial activity while they are constructed in atomic level. The unique and major task in the synthesis of nanoparticle is choosing of an advanced and ecofriendly method. Nevertheless, physical and chemical methods of synthesis of nanoparticles are too expensive and environmentally unsound. In this study, the green synthesis of nanoparticle’s production methods was evaluated on the basis of variable literatures. Currently, there is a better possibility of using green synthesis of silver nanoparticles, especially a plant, bacterial and fungal production of nanoparticles which is emerging as a novel ecofriendly technique. The growth rate of bacterial culture, the extract of plant secondary metabolite and mycelial surface area of fungus are the main comprehensible mechanism in green synthesis of silver nanoparticles. The silver nanoparticles, which are produced through green biosynthesis is safe and hold a better possibility to be administered for medical and agricultural usages. Over all we found that the fungal green biosynthesis of silver nanoparticles is considered more preferable and is excellently chosen in it in industrial level production.

Ocimum gratissimum L. is a perennial herbaceous plant used in the treatment of fungal and bacterial infections. Green synthesis has provided cost effective, environment friendly procedure and raising safe strategies for the synthesis of nanoparticles. This study was aimed at investigating the potential of O. gratissimum for the synthesis of selenium nanoparticles (SeNPs) and their antimicrobial activities. Phytochemical screening on aqueous extract was carried out using standard procedures. Selenium nanoparticles was biosynthesized by O. gratissimum and characterized using Visual detection, UV-Visible spectroscopy, Scanning Electron Microscope, Transmission Electron Microscope, Energy dispersive X-ray, Fourier Transform Infra-red spectroscopy and X-ray diffraction spectroscopy. Antimicrobial activity of the biosynthesized selenium nanoparticles by O. gratissimum was done using agar well diffusion method. Saponins, tannins, cardiac glycosides, terpenoids and phenols were present. The biosynthesized SeNPs had a strong plasmon resonance band at 300 nm, changes in colour from dark brown to ruby red. The SeNPs were spherical and aggregated with varying shapes and size ranged from 20 – 50 nm. Strong signal of selenium element was observed. Hydroxyl, esters, aldehyde, alkane and amine are present and responsible for the efficient stabilization and bioreduction of Selenium nanoparticle. Furthermore, biosynthesized SeNPs by O. gratissimum (OGSeNPs) exhibited higher antimicrobial activity against both Gram ositive and Gram negative bacteria. Green synthesis of nanoparticles is a promising method in the biomedical field, due to its high bioactive components.

WITHDRAWN: Characterization, antioxidant and antimicrobial activity of silver nanoparticles synthesized using marine endophytic fungus- Cladosporium cladosporioides

In recent years, there has been an increasing interest in the development of plant‐based nanoparticles due to their numerous benefits over conventional physio‐chemical methods, including sustainability and environmental safety. Green synthesis, a process that produces safe and sustainable goods without the use of harsh chemicals or other harmful processes, is gaining popularity. The current study focuses on the green synthesis of copper oxide nanoparticles using Piper nigrum leaf extracts, their characterization, and applications. The synthesis of nanoparticles was confirmed by changes in colour, further endorsed by UV–visible spectroscopy. Copper oxide (CuO) nanoparticles were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). CuO nanoparticle sizes ranged between 58.23 and 69.89 nm and were spherical in shape. FTIR results indicated a functional group capped on the nanoparticle surface. The antibacterial activity of the copper oxide nanoparticles was tested, and they exhibited the significant decrease in bacterial concentration and the largest zone of inhibition, making them an efficient disinfectant. Antimicrobial activity against Bacillus subtilis and Escherichia coli was observed. Furthermore, the synthesized CuO nanoparticles exhibited a high affinity for safranin dyes and demonstrated maximum removal efficiency. This makes them an effective agent for removing dyes in wastewater from industries such as clothing manufacturing. Safranin dye was successfully removed with an efficiency of 78% using nanoparticles. In conclusion, the green synthesis of copper oxide nanoparticles using plant extracts presents an eco‐friendly and sustainable approach for producing nanoparticles with a wide range of potential applications.

Nanotechnology deals with the synthesis of nanoparticles with controlled size, shape and dispersity of materials at the nanometer scale and their potential use for human well bein g. This leads to focus on “Green Synthesis” of nanoparticles which seems to be an easy, efficient and eco- friendly approach. In this study, the green synthesis of silver nanoparticles was carried out using root extract of Morinda pubescens as reducing agent. It was found that aqueous silver ions can be reduced by aqueous root extr act of Morinda pubescens to generate extremely stable silver nanoparticles in water. The silver nanoparticles (AgNPs) formation was confirmed by the colour change of the mixture and further confirmed by spectral analysis. UV-Visible spectrum of the aqueous medium containing silver nanoparticles showed a peak around 416.5 nm. FT -IR analysis confirmed reduction of Ag+ ions to Ag0 ions in synthesized silver nanoparticles. Further, the produced silver nanoparticles showed bactericidal effect against Staphylococcus aureus, Escherichia coli and Aspergillus niger. From this study concluded that the root extract of Morinda pubescens reduces Ag+ to Ag0 and enhances synthesis of silver nanoparticles with antimicrobial activity.

Nanoparticles are being viewed as fundamental building blocks of nanotechnology. The most important and distinct property of nanoparticles is that they exhibit larger surface area to volume ratio. The most effectively studied nanoparticles today are those made from noble metals, in particular Ag, Pt, Au, and Pd. Silver nanoparticles have various applications such as biomedical devices, biosensors, catalysis, electronics and pharmaceuticals. In this study rapid, simple and eco-friendly approach was applied for synthesis of silver nanoparticles (AgNPs) using Kinnow mandarian aqueous peel extract as the reducing agent as well as capping agent. The reaction process is simple for the formation of stable silver nanoparticles at room temperature by using the bio waste of the fruit peel. The synthesis of nanoparticles has been monitored by UV–Visible spectroscopy (UV–Vis). Synthesized nanoparticles are characterized by Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM). In addition the synthesized nanoparticles were incorporated in the shampoo formulation. The shampoo formulations containing synthesised silver nanoparticles were evaluated for physical appearance, solid content, pH, foamability, surface tension and dirt dispersion test. Anti microbial activity was tested against pathogenic microbes Escherichia coli. and Candida albicanas. It was concluded that shampoo formulation containing silver nano particles showed enhanced antimicrobial activity as compared to shampoo formulation not containing silver nano particle and standard antimicrobial agents.

Green synthesis of copper oxide nanoparticles using Rosmarinus officinalis leaf extract and evaluation of its antimicrobial activity

This work deals with the identification of a predominant thraustochytrid strain, the optimization of culture conditions, the synthesis of nanoparticles, and the evaluation of antioxidant and antimicrobial activities in biomass extracts and nanoparticles. Thraustochytrium kinnei was identified as a predominant strain from decomposing mangrove leaves, and its culture conditions were optimized for maximum biomass production of 13.53 g·L−1, with total lipids of 41.33% and DHA of 39.16% of total fatty acids. Furthermore, the strain was shown to synthesize gold and silver nanoparticles in the size ranges of 10–85 nm and 5–90 nm, respectively. Silver nanoparticles exhibited higher total antioxidant and DPPH activities than gold nanoparticles and methanol extract of the strain. The silver nanoparticles showed higher antimicrobial activity than gold nanoparticles and petroleum ether extract of the strain. Thus, Thraustochytrium kinnei is proven to be promising for synthesis of silver nanoparticles with high antioxidant and antimicrobial activity.

The Ber plant, also known as Ziziphus mauritiana, is a medium-sized tropical fruit tree in India. It is a member of the Rhamnaceae family. Z. mauritiana's pharmacological and nutritional potential has been extensively studied. Numerous minerals, including iron, copper, zinc, potassium, calcium, and magnesium are abundant in it. This plant's edible portions are high in vitamin A, vitamin B complex, and ascorbic acid. The plant parts exhibit anti-inflammatory, anti-allergy, and anti-cancer activities, according to several research. Additionally, it has been mentioned as a pharmacological agent for liver ailments, diabetes, TB, wound healing, asthma, and blood-related illnesses. Unlike leaves, which have been used as reducing and capping agents by many nanotechnologists in the synthesis of nanoparticles, bimetallic Copper-Zinc nanoparticles were made using leaves as a plant part. Pathogenic pathogens confirmed the presence of bioactive compounds in the plant that had detectable antibacterial activity against bacteria. Since they are believed to be safe for use in food products, copper and zinc nanoparticles are frequently utilized as food additives and packaging. Bimetallic Cu-Zn nanoparticles were shown to exist using UV-Visible spectroscopy and a simple visual color shift. This is the first report of the synthesis of Cu-Zn bimetallic nanoparticles from Ziziphus Mauritiana leaves, and bimetallic have been more in demand than monometallic due to their antimicrobial activity, superior optical and magnetic properties.

So far, several studies have focused on the synthesis of metallic nanoparticles making use of extracts from the fruit of the plants from the genus Capsicum. However, as the fruit is the edible, and highly commercial, part of the plant, in this work we focused on the leaves, a part of the plant that is considered agro-industrial waste. The biological synthesis of gold (AuNPs) and silver (AgNPs) nanoparticles using aqueous extracts of root, stem and leaf of Capsicum chinense was evaluated, obtaining the best results with the leaf extract. Gold and silver nanoparticles synthesized using leaf extract (AuNPs-leaf and AgNPs-leaf, respectively) were characterized by UV-visible spectrophotometry (UV-Vis), Fourier Transform Infrared Spectroscopy with Attenuated Total Reflection (FTIR-ATR), X-ray Photoelectron Spectroscopy (XPS), Ultra Hight Resolution Scanning Electron Microscopy coupled to Energy-Dispersive X-ray spectroscopy (UHR-SEM-EDX) and Transmission Electron Microscopy (TEM), and tested for their antioxidant and antimicrobial activities. In addition, different metabolites involved in the synthesis of nanoparticles were analyzed. We found that by the use of extracts derived from the leaf, we could generate stable and easy to synthesize AuNPs and AgNPs. The AuNPs-leaf were synthesized using microwave radiation, while the AgNPs-leaf were synthesized using UV light radiation. The antioxidant activity of the extract, determined by ABTS, showed a decrease of 44.7% and 60.7% after the synthesis of the AuNPs-leaf and AgNPs-leaf, respectively. After the AgNPs-leaf synthesis, the concentration of polyphenols, reducing sugars and amino acids decreased by 15.4%, 38.7% and 46.8% in the leaf extract, respectively, while after the AuNPs-leaf synthesis only reducing sugars decreased by 67.7%. These results suggest that these groups of molecules are implicated in the reduction/stabilization of the nanoparticles. Although the contribution of these compounds in the synthesis of the AuNPs-leaf and the AgNPs-leaf was different. Finally, the AgNPs-leaf inhibited the growth of S. aureus, E. coli, S. marcescens and E. faecalis. All of them are bacterial strains of clinical importance due to their fast antibiotic resistance development.

Green synthesis of silver nanoparticles is cost effective and encourages the use of non‐toxic chemicals. The biological sources of reductants have trouble free protocols and when applied for human health associated field, is an easy approach for maintaining aseptic environment during the synthesis of nanoparticles. Microalgae are used as a source of natural colours and exhibit extensive applications as natural colorants in nutraceuticals, cosmetics and pharmaceutical industries. The use of Navicula cincta microalgae in the biogenic synthesis of silver nanoparticles is unexplored and underexploited. In this work, silver nanoparticles synthesised using algal extract by sunlight method were characterised by UV–Visible spectroscopy, X‐ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, Fourier transform infrared spectroscopy and particles size analyser. The antimicrobial activity of nanosilver against seven bacteria, Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Shigella flexneri, Vibrio cholera and Salmonella typhi and four fungi Aspergillus flavus, Aspergillus niger, Aspergillus fumigatus and Rhizopus stolonifer are investigated using agar well diffusion technique and compared with standard antibiotics namely Chloramphenicol and Nystatin.

The use of natural plant extracts in the synthesis of nanoparticles provides advancement over chemical and physical methods, due to its cost effectiveness and environment friendly nature. In this study, silver nanoparticles (AgNPs) have been synthesized with simple and green technique using Pluchea sericea plant leaf extract as reducer as well as stabilizer. The characterization and properties of AgNPs were investigated using UV–visible spectroscopic techniques, energy dispersive X-ray spectrometers (EDS), zeta potential and dynamic light scattering. The UV–visible spectroscopic analysis showed the absorbance peak at 487 nm, which indicates the synthesis of silver nanoparticles. The experimental results showed silver nanoparticles having Z-average diameter of 59.20 nm with higher stability (−70.9 mV). The EDS analysis also exhibits presentation of silver element. Additionally, the different concentrations of AgNPs (25, 50, 75 and 100 %) showed antibacterial activity against Acinetobacter calcoaceticus. Finally, AgNPs from leaf extracts of P. sericea may be used for antimicrobial activity against A. calcoaceticus. However, further studies will be needed to fully understand the antimicrobial activity of AgNPs and to determine if the microorganism can develop resistance toward these nanoparticles.

Biosynthesis of silver nanoparticles from Tribulus terrestris and its antimicrobial activity: A novel biological approach

Nanotechnology has become a trending area in the field of science and technology. It has made great advances with the development of functional, engineered nanoparticles. The better advancements made towards the synthesis of nanoparticles using plant materials have become a major focus of researchers because of their advantages including high stability and loading capacity. Recently, zinc oxide nanoparticles have drawn the attention of several researchers owing to their several biological applications including anticancer and antimicrobial activities. Different techniques have been employed for the production of gold nanoparticles due to their elaborated applications in different interdisciplinary fields. The synthetic procedure of plant-based nanoparticles has attracted a keen interest of various researchers as the synthesis is comparatively fast, safe and light and can be followed under basic room conditions without the requirement of any advanced synthesis requirements. Every part of the plants can be used for the synthesis of nanoparticles. Gold nanoparticles play a pivotal role as the most active, environment friendly and biocompatible towards a greener approach. In this review paper, we report highlighted about the various plants extract, which have been used for the synthesis of gold nanoparticles and their biological evaluation based on previous year’s research and scientific papers and journal and articles.

To meet the increasing demands for commercial nanoparticles new eco-friendly methods of synthesis are being discovered. Plant mediated synthesis of nanoparticles offers single step, easy extracellular synthesis of nanoparticles. We report the synthesis of antibacterial Silver nanoparticles using leaf extract of the medicinal plant, Tinospora cordifolia. The leaf extract was prepared by boiling chopped leaves of Tinospora cordifolia in deionized water for 10 min and filtering the mixture with Whatman filter paper No.1. The filtrate was used as a reducing agent and stabilising agent for AgNO3. On adding 1 mM solution of Silver nitrate to the leaf extract and stirring at 75 °C for 25 min, a change in colour from yellow-brown to brown-black specified the production of Silver nanoparticles. The formation of Silver nanoparticles was monitored by UV-visible spectroscopy and further characterization of the synthesized Silver nanoparticles was done by XRD studies. The antibacterial studies were performed on Gram negative and Gram positive pathogens, Salmonella typhi, Pseudomonas aeruginosa, Enterobacter aerogenes and Staphylococcus aureus, by agar well diffusion method, on Mueller Hinton agar medium. The Silver nanoparticles synthesized from Tinospora cordifolia leaf extract were found to have antimicrobial activity against these Gram negative and Gram positive pathogenic bacteria.