Biogenic Synthesis Of Metal Nanoparticles Research Articles

Instant green synthesis: obtaining stable nanoparticles and understanding the extract's behavior in the particle formation mechanism

Numerous plant extracts are abundant in biomolecules that can be employed in the biogenic synthesis of metallic nanoparticles owing to their potent reducing capabilities. The mechanism by which biomolecules act as reducers and expedite the reduction of silver ions remains poorly understood. This study presents an instantaneous and environmentally friendly synthesis of silver nanoparticles (AgNPs) using varying concentrations of commercially available green tea and concentrations of a dextrose-reducing solution. The AgNPs formed instantaneously, likely due to the competitive reaction between the polyphenols present in green tea and the dextrose. The best AgNPs produced using a diluted green tea solution at a concentration of 0.05 g of tea/ml and 100 μl of dextrose solution exhibited high stability over a period of 90 days, as confirmed by UV–vis spectroscopy and dynamic light scattering. The results of antioxidant properties from diluited tea showed 2,2-diphenyl-1-picrylhydrazyl (DPPH) 0.013 ± (0.1) μmol Trolox Equivalent Anyioxidant Capacity (TEAC) TEAC/g, Ferric Reducing Antioxidant Power (FRAP) 10.3 ± (0.1) μmol TEAC/g and Total Polyphenol Content (TPC) 0.12 ± (.001) μgGAE(Galic Acid Equivalent)/g). The resulting nanoparticles are extremely small, measuring approximately 30 to 50 nm in size, and exhibit a spherical morphology as evidenced by SEM imaging. The plasmon bandwidth is better in more diluted tea and higher proportions of dextrose added than the others condition of synthesis. Probably, the results of 2nd extraction of green tea diluted can be evidence that phenolic compounds, mainly, caffeine and gallic acid, are contributing to forming and stabilizing the silver nanoparticles. This fundamental knowledge showed the method employed is ecologically sound and adheres to green principles.

Bioinorganic metal nanoparticles and their potential applications as antimicrobial, antioxidant and catalytic agents: a review

Abstract This review article covers the biogenic synthesis of metal nanoparticles (MNPs) having definite shape and size while using extract obtained from different biological sources such as bacteria, fungi, algae and plants. These biological materials are composed of chloroplast, thylakoid, different types of enzymes extracted from different biogenic sources, different phytochemicals such as phenols, flavonoids, and citric acid having functional groups such as sulfate, carboxyl, amino, amide and hydroxyl groups. These functional groups and enzymes act as efficient reductants to convert metal ions into metal atoms and alternatively metal atoms combine to form MNPs while long hydrocarbon chains present in these bio-macromolecules act as cage to stabilize them for prolong time. Effect of nature of source extract, different reaction conditions such as extract amount, salt amount and solvent used during MNPs preparation process have been critically discussed here in detail. Use of synthesized bioinorganic NPs in various areas including their effectiveness in fighting against bacteria, viruses, fungi, cancer, inflammation, and their potential role in catalytic reduction of environmental harmful substances into friendly products has also been described in a clear and concise manner along with their future consideration.

Titanium biogenic nanoparticles to help the growth of Trichoderma harzianum to be used in biological control

BackgroundThe biogenic synthesis of metallic nanoparticles is a green alternative that reduces the toxicity of this nanomaterials and may enable a synergy between the metallic core and the biomolecules employed in the process enhancing biological activity. The aim of this study was to synthesize biogenic titanium nanoparticles using the filtrate of the fungus Trichoderma harzianum as a stabilizing agent, to obtain a potential biological activity against phytopathogens and mainly stimulate the growth of T. harzianum, enhancing its efficacy for biological control.ResultsThe synthesis was successful and reproductive structures remained in the suspension, showing faster and larger mycelial growth compared to commercial T. harzianum and filtrate. The nanoparticles with residual T. harzianum growth showed inhibitory potential against Sclerotinia sclerotiorum mycelial growth and the formation of new resistant structures. A great chitinolytic activity of the nanoparticles was observed in comparison with T. harzianum. In regard to toxicity evaluation, an absence of cytotoxicity and a protective effect of the nanoparticles was observed through MTT and Trypan blue assay. No genotoxicity was observed on V79-4 and 3T3 cell lines while HaCat showed higher sensitivity. Microorganisms of agricultural importance were not affected by the exposure to the nanoparticles, however a decrease in the number of nitrogen cycling bacteria was observed. In regard to phytotoxicity, the nanoparticles did not cause morphological and biochemical changes on soybean plants.ConclusionThe production of biogenic nanoparticles was an essential factor in stimulating or maintaining structures that are important for biological control, showing that this may be an essential strategy to stimulate the growth of biocontrol organisms to promote more sustainable agriculture.Graphical

Biosynthesis of silver nanoparticles using Citrus hystrix leaf extract and evaluation of its anticancer efficacy against HeLa cell line

Background Cervical cancer continues to be the leading cause of death worldwide despite the availability of many therapeutic options. Biogenic synthesis of metal nanoparticles paves a new way for the development of targeted drug delivery modalities of cancer therapeutics. Objective In this study, we demonstrate the efficacy of biosynthesized silver nanoparticles from methanolic leaf extract of Citrus hystrix as an anticancer agent used against cervical cancer cell line HeLa. Methods The addition of 1 mM silver nitrate to methanolic leaf extract of Citrus hystrix resulted in the biosynthesis of silver nanoparticles during the reaction mixture and was incubated in the dark for 1 h at pH 9 with gentle stirring. Characterization of synthesized NPs was carried out using various analyses. MTT assay, DAPI, AO/EB double staining, and reverse transcriptase-PCR (RT-PCR) analysis were carried out to evaluate the cytotoxic activity of Citrus hystrix mediated green synthesized silver nanoparticles (ChAgNPs). Results and conclusion The absorption band at 430 nm, as shown by UV–vis spectroscopy revealed the formation of AgNPs. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis shows that most of the ChAgNPs were spherical in shape and X-ray diffraction (XRD) patterns revealed the crystalline nature of the particles. Moreover, its potent cytotoxic effect on the HeLa cell line was analyzed using MTT assay with an IC50 value of 56 µg/ml by decreasing the cell viability in a dose and time-dependent manner. The induced apoptotic activity was confirmed by DAPI and double staining methods. Autophagic and apoptotic mediated cell death in ChAgNPs treated HeLa cell line was confirmed by staining procedures and RT-PCR methods.

Biogenic Synthesis of Zinc Nanoparticles, Their Applications, and Toxicity Prospects.

Nanofertilizers effectively deliver the micronutrients besides reducing the phytotoxicity and environmental damage associated with chemical fertilizers. Zinc, an essential micronutrient, is significant for chloroplast development, activation of certain enzymes, and primary metabolism. Nano zinc oxide (ZnO) is the most widely used zinc nanoparticle. Concerns regarding the toxicity of conventional physical and chemical methods of synthesizing the nanoparticles have generated the need for a green approach. It involves the biogenic synthesis of metallic nanoparticles using plants and microorganisms. Microbe-mediated biogenic synthesis of metallic nanoparticles is a bottom-up approach in which the functional biomolecules of microbial supernatant reduce the metal ions into its nanoparticles. This review discusses the biological synthesis of nano-ZnO from microorganisms and related aspects such as the mechanism of synthesis, factors affecting the same, methods of application, along with their role in conferring drought stress tolerance to the plants and challenges involved in their large-scale synthesis and applications.

Phytofabricated Silver Nanoparticles (AgNPs) Applied in Vase Solution as a Novel Anti-Microbial Agent for Enhancing the Vase-life of Cut-Rose Flower

Plant extract has been exploited for biogenic synthesis of metallic nanoparticles. This is considered as the promising alternative routes of chemical and physical synthesis methods owing to their abundancy in nature and ecofriendly friendly synthesis protocol. Rose is the top-ranked and universally favorite cut flower. Poor post-harvest management deteriorates the quality and reduces the vase life. Microbial proliferation of the stem base in the vase solution is a concern for these cut flowers that shortens their vase-life. To overcome this problem, a smart solution i.e. phytofabricated silver nanoparticles have been shown to act as anti-microbial agent. In this study, leaf extracts of Camellia sinensis were exploited to fabricate biogenic silver nanoparticles which showing UV-peak absorption ranging from 412-500 nm. This biogenic silver nanoparticles were applied @ 0.01, 0.05 and 0.1mM and compared with a control (without AgNPs) and silver nitrate (AgNO3). Interestingly, AgNPs showed a strong antimicrobial activity in vase solution and cut roses extended their vase life up to 13 days compared to 8 days in control and 9 days in AgNO3. Statistical differences in flower opening, bacterial growth (CFUmL−1) in vase solutions, water uptake, relative fresh weight and vase life of cut roses were found among treatments. In vitro microbial analysis and microscopic investigation of vessels showed that the development of microorganisms was reduced by a high concentration of AgNPs (0.1mM) at the cut end of flower and improving water uptake that followed by extended flowers vase life. The unique phytofabricated AgNPs technology can serve as a promising preservative to increase the ornamental value of cut rose flowers. Taken all together, applied phytofabricated AgNPs in vase solution significantly enhance vase life of cut rose flowers over control.

Green Synthesis of Silver Nanoparticles Using Natural Extracts with Proven Antioxidant Activity.

Natural extracts are a rich source of biomolecules that are useful not only as antioxidant drugs or diet supplements but also as complex reagents for the biogenic synthesis of metallic nanoparticles. The natural product components can act as strong reducing and capping substrates guaranteeing the stability of formed NPs. The current work demonstrates the suitability of extracts of Camellia sinensis, Ilex paraguariensis, Salvia officinalis, Tilia cordata, Levisticum officinale, Aegopodium podagraria, Urtica dioica, Capsicum baccatum, Viscum album, and marine algae Porphyra Yezoensis for green synthesis of AgNPs. The antioxidant power of methanolic extracts was estimated at the beginning according to their free radical scavenging activity by the DPPH method and reducing power activity by CUPRAC and SNPAC (silver nanoparticle antioxidant capacity) assays. The results obtained by the CUPRAC and SNAPC methods exhibited excellent agreement (R2~0.9). The synthesized AgNPs were characterized by UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), dynamic light scattering (DLS) particle size, and zeta potential. The UV-vis absorption spectra showed a peak at 423 nm confirming the presence of AgNPs. The shapes of extract-mediated AgNPs were mainly spherical, spheroid, rod-shaped, agglomerated crystalline structures. The NPs exhibited a high negative zeta potential value in the range from −49.8 mV to −56.1 mV, proving the existence of electrostatic stabilization. FTIR measurements indicated peaks corresponding to different functional groups such as carboxylic acids, alcohol, phenol, esters, ethers, aldehydes, alkanes, and proteins, which were involved in the synthesis and stabilization of AgNPs. Among the examined extracts, green tea showed the highest activity in all antioxidant tests and enabled the synthesis of the smallest nanoparticles, namely 62.51, 61.19, and 53.55 nm, depending on storage times of 30 min, 24 h, and 72 h, respectively. In turn, the Capsicum baccatum extract was distinguished by the lowest zeta potential, decreasing with storage time from −66.0 up to −88.6 mM.

Green Synthesis, Characterization, and Antibacterial Properties of Silver Nanoparticles Obtained by Using Diverse Varieties of Cannabis sativa Leaf Extracts.

Cannabis sativa L. (hemp) is a plant used in the textile industry and green building material industry, as well as for the phytoremediation of soil, medical treatments, and supplementary food products. The synergistic effect of terpenes, flavonoids, and cannabinoids in hemp extracts may mediate the biogenic synthesis of metal nanoparticles. In this study, the chemical composition of aqueous leaf extracts of three varieties of Romanian hemp (two monoecious, and one dioecious) have been determined by Fourier-Transformed Infrared spectroscopy (FT-IR), high-performance liquid chromatography, and mass spectrometry (UHPLC-DAD-MS). Then, their capability to mediate the green synthesis of silver nanoparticles (AgNPs) and their pottential antibacterial applications were evaluated. The average antioxidant capacity of the extracts had 18.4 ± 3.9% inhibition determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH•) and 78.2 ± 4.1% determined by 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS™) assays. The total polyphenolic content of the extracts was 1642 ± 32 mg gallic acid equivalent (GAE) L−1. After this, these extracts were reacted with an aqueous solution of AgNO3 resulting in AgNPs, which were characterized by UV−VIS spectroscopy, FT-IR, scanning electron microscopy (SEM-EDX), and dynamic light scattering (DLS). The results demonstrated obtaining spherical, stable AgNPs with a diameter of less than 69 nm and an absorbance peak at 435 nm. The mixture of extracts and AgNPs showed a superior antioxidant capacity of 2.3 ± 0.4% inhibition determined by the DPPH• assay, 88.5 ± 0.9% inhibition as determined by the ABTS•+ assay, and a good antibacterial activity against several human pathogens: Escherichia coli, Klebsiella pneumoniae, Pseudomonas fluorescens, and Staphylococcus aureus.

Biogenic synthesis of metallic nanoparticles: Principles and applications

Abstract The synthesis of metallic Nanoparticles (NPs) has gathered utmost interest over the past decades thank to their distinctive properties that build them applicable in several fields further as including science and technology. This main methods utilized in their synthesis are non-environmental friendly. This review paper describes the green methods within the synthesis of biogenic NPs further as their mechanisms involving various plant extracts which are non toxic, environment friendly and value effective. The natural plant extracts contains metabolites like flavonoids, terpenoids, polyphenols, alkaloids, etc which acts as both reduction and stabilization agents for synthesizing biogenic NPs with desired shape and size. During this review paper the employment of assorted plant extracts additionally the employment of bacteria, fungi, proteins within the biogenic synthesis of NPs has been delineated shortly. Ultimately the importance and applications of biogenic NPs has also been expressed.

Biogenic α-Fe2O3 Nanoparticles Enhance the Biological Activity of Trichoderma against the Plant Pathogen Sclerotinia sclerotiorum

The biogenic synthesis of metallic nanoparticles can contribute to resolving problems related to pests and soil fertilization. Among the different types of metallic nanoparticles, iron nanoparticles have shown good results, especially concerning toxicity because this metal is an essential micronutrient for all plants and can assist their growth, increasing the levels of carbohydrates, proteins, and chlorophyll. This work performed the green synthesis of biogenic iron oxide nanoparticles using the biological control agent Trichoderma harzianum as a stabilizing agent. The physicochemical properties of the nanoparticles were evaluated using the following techniques: dynamic light scattering, nanoparticle tracking analysis, scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. Cytotoxicity was evaluated using different cell lines, while comet and Allium cepa assays were used to assess genotoxicity. In addition, as a proof of concept, the biological activity of the nanoparticles against the pathogen Sclerotinia sclerotiorum (white mold) was evaluated using an in vitro antifungal activity test. The effect of the nanoparticles on seed germination was also evaluated. The results indicated that the nanoparticles consisted of hematite (α-Fe₂O₃) and had a mean size diameter of 207 ± 2 nm, polydispersity index of 0.45 ± 0.07, and zeta potential of 13 ± 2 mV. The biogenic iron oxide nanoparticles did not alter cell viability, compared to the controls, and did not lead to changes in the mitotic index, at the concentrations used. Furthermore, they were able to increase the proliferation of Trichoderma, which led to the inhibition of emergence of the pathogen S. sclerotiorum and did not affect the germination of the seeds. Therefore, the green synthesis of biogenic iron oxide nanoparticles based on T. harzianum is an attractive option for pest control, aiming at sustainable agricultural practices.

A review on biogenic synthesis of metal nanoparticles using marine algae and its applications

Marine algae have long been explored as food, feed, additives, drugs, and pesticides, yet now the framework is moving towards the algae mediated green synthesis of nanoparticles (NPs). This work is expanding step by step, like algae, are a rich origin of natural compounds. Recently, algae capped and stabilized NPs have picked up far and wide consideration as a less toxic, easy handling, cost effective, eco-friendly, usage in several science fields in nano size, safer to use, and greener method. The natural substance from algae acts as capping or reducing and stabilizing agent in the metal salts to metal, metal oxide, or bimetallic NPs conversion. The NPs using algae could either be intracellular or extracellular relying upon the area of NPs. Among the different scope of algae, reviews are explored in the previous report, still, different NPs using algae and their characterization, mechanism of activity is yet to be summarized. Because of the biocompatibility, good and remarkable physicochemical properties of NPs, the algal biosynthesized NPs have additionally been read for their biomedical applications, which include antibacterial, antioxidant, free radical scavenging, antifungal, anticancer, and biocompatibility properties. In this survey, the reasoning behind the algae mediated biosynthesis of various NPs from different algae origin have been explored. Besides, a piece of knowledge into the component of biosynthesis of NPs from marine algae and their biomedical applications has been summarized.

An eco-friendly Gnaphalium polycaulon mediated silver nanoparticles: Synthesis, characterization, antimicrobial, wound healing and drug release studies

Nowadays, biogenic synthesis of metal nanoparticles using plants has attracted greater in a wide range of pharmaceutical interest owing to posses suitable alternative treatment strategies than existing conventional chemical methods. In the present study, we reported the facile, cost-effective, reproducible biogenic synthesis of silver nanoparticles (Gp-AgNPs) using Indian folk medicinal plant, Gnaphalium polycaulon (Gp) leaves extract. The formation of Gp-AgNPs was confirmed by the assistance of different sophisticated analytical techniques. The synthesized Gp-AgNPs exhibited the maximum SPR peak at 365 nm. FT-IR result indicated the presence of various active functional groups in the extract, which may be responsible for the reduction and stabilization of the Gp-AgNPs. The spherical and triangle shapes with <50 nm size of Gp-AgNPs were authorized by SEM and HR-TEM analyses. The Gp-AgNPs exhibited superior antimicrobial activity against selective Gram-positive (Staphylococcus aureus), Gram-negative (Escherichia coli) bacterial, and fungal (Candida albicans) pathogens. The synthesized Gp-AgNPs suppressed the growth of most dreadful pathogens associated with wound infection. The efficiency of Gp-AgNPs on fastening the rate of healing of a wound was confirmed by in vivo studies. in vitro drug-releasing activity was determined by in vitro dialysis bag method. Concomitantly, the current study is the first attempt to exemplify the potent broad-spectrum of antimicrobial and wound healing efficacies of Gp-AgNPs from G. polycaulon, which could plausibly be a promising biomaterial for various biomedical applications.

Metal Nanoparticles from Algae: A Green Approach for the Synthesis, Characterization and their Biological Activity

In recent time, green synthesis of metal nanoparticles is the latest developing technology and received prodigious interest because it is easy, environmentally pristine, non-fouling, antitoxic, and lowcost approach. Green route of biogenic synthesis of metal nanoparticles via microbes such as bacteria, fungi, virus, yeast and algae has the potential to deliver sustainable and enviro safe protocol. Green synthesized metal nanoparticles are the most optimistic and novel agent for various catalytic and biological activities as antibacterial, antiviral, anticancer etc. without any toxic effects. Here, we reviewed algae-mediated green synthesis of metal and metal oxide nanoparticles and their biological activity. Algae are photoautotrophic, eukaryotic, aquatic, unicellular or multicellular organisms. Algae commonly used for biosynthesis because they grow rapidly, their biomass growth on average ten times faster than higher plants and easy to handle experiments with algal species. Different algal strains such as red, green and brown algae are using for the green synthesis of metal nanoparticles. Algae contain bioactive molecules and secondary metabolites that act as reducing, capping and stabilizing agent for manufacturing in nanoparticles. Biogenically synthesized metal and metal oxide nanoparticles characterized by different techniques such as UV-visible spectroscopy, SEM (scanning electron microscopy), HR-TEM (high-resolution transmission electron microscopy), XRD (X-ray diffraction), TGA (thermogravimetric analysis), DLS (dynamic light scattering) zeta potential and exhibited biological activity. In future, research algal production of metal nanoparticles can be explored by the use of different microalgae and their applications in different areas such as biological activity, catalytic activity in the synthesis of organic compounds, medical diagnose and synthesis of nanocomposite, lipid nanoparticles and antibiofilm.

In Vitro Antimicrobial and Antioxidant Activity of Biogenically Synthesized Palladium and Platinum Nanoparticles Using Botryococcus braunii.

The spread of infectious diseases and the increase in drug resistance among microbes has forced researchers to synthesize biologically active nanoparticles. Ecofriendly procedures for the synthesis of nanoparticles are improving day by day in the field of nanobiotechnology. In the present study we used extract of the green alga Botryococcus braunii for the synthesis of palladium and platinum nanoparticles and evaluated their antimicrobial and antioxidant activity. Green alga was collected from Udaisagar Lake, Udaipur (Rajasthan, India) and isolated by serial dilution method and grown on Chu-13 nutrient medium. The characterization of alga synthesized palladium and platinum nanoparticles was carried out using X-ray diffraction and scanning electron spectroscopy. The zone of inhibition was measured by agar well plate method and minimum inhibitory concentration was determined by agar dilution assay for antimicrobial activity. The antioxidant activity of the nanoparticles was also studied by 1,1-diphenyl-2-picrylhydrazyl method. Stable palladium and platinum nanoparticles were successfully produced using green alga. The XRD pattern revealed the crystalline nature and scanning electron micrographs showed the morphology of biogenically synthesized metal nanoparticles. Fourier transform infrared measurements showed all functional groups having control over stabilization and reduction of the nanoparticles. The green synthesized nanoparticles exhibited antimicrobial activity against gram-positive and gram-negative bacterial strains, antifungal activity against a fungus, and antioxidant activity. The biogenic synthesis of metal nanoparticles can be a promising process for the production of other transition metal nanoparticles and new nanocatalysts will revolutionize the synthesis of organic heterocycles.

Bacterium Mediated Facile and Green Method for Optimized Biosynthesis of Gold Nanoparticles for Simple and Visual Detection of Two Metal Ions

The biogenic synthesis of metal nanoparticles (MNPs) is gaining impetus and widely used for being an eco-friendly approach. In this study, bacterium Pseudomonas stutzeri was demonstrated for use in the biogenic synthesis of gold nanoparticles (AuNPs). Optimization of conditions indicated that 3 mM chloroauric acid (HAuCl4), pH 9, incubation at 80 °C for 60 min, etc. were optimum for AuNPs synthesis. AuNPs were then synthesized with these optimum conditions and characterized using various spectroscopic and imaging techniques. The initial screening of 22 different metal ions for colloidal AuNPs based visual and UV–Vis. spectra based sensing indicated that two metal ion namely Manganese (Mn2+) and Platinum (Pt2+) caused both, the change in color from ruby red to dark brown and purple-blue along with spectral shifts of 23 and 21 nm respectively, therefore, could be easily detected. The test of sensitivity indicated that 100 and 190 ppm of Mn2+ and Pt2+ respectively were the limit of detections and, the assay quantitatively recovered Mn2+ and Pt2+ in the range of 70–150% with considerable accuracy and precision.

Biogenic synthesis of gold nanoparticles using Jasminum auriculatum leaf extract and their catalytic, antimicrobial and anticancer activities

Usage of plant sources for the biogenic synthesis of metal nanoparticles is an innovative area in modern nanotechnology research. In the present article, we have reported a trouble-free, environmentally benign approach for the biogenic synthesis of gold nanoparticles (Au NPs) using the Jasminum auriculatum leaf extract, which acts as a stabilising and reducing agents. The surface plasmon resonance peak at 547 nm in the UV–Visible absorption spectrum confirmed the biogenic Au NPs synthesis. TEM & SEM analysis revealed that the biogenic Au NPs are spherical with an average size of 8–37 nm. The catalytic reduction activity on p-nitrophenol revealed that the biogenic Au NPs are a versatile candidate for heterogeneous catalysis. The pH stability study using phosphate buffer solution confirmed the compatibility of our gold nanoparticles for biomedical applications. The cytotoxicity of the biogenic Au NPs revealed that the nanoparticles manifested a significant dose-dependent inhibitory effect in the proliferation of the human cervical cancer cell line with the IC50 value of 104 μg/ml. The biogenic gold nanoparticles showed tremendous antimicrobial commotion against human pathogenic bacteria (Streptococcus pyogenes, Staphylococcus aureus, Escherichia coli and Klebsiella pneumonia) and fungus (Candida albicans, Aspergillus fumigatus, Lecanicillium lecanii and Trichoderma viride).

Time and Size-dependent Biogenically Synthesized Nanoparticles Using Fungus Fusarium Oxysporum: A Review on their Preparation, Characterization and Biological Activities

In recent time, green synthesis of Metal Nanoparticles (MNPs) is the latest developing technology and received exceptional interest because it is simple, eco-friendly, pollutant-free, nontoxic, and a low-cost approach. Green route of biogenic synthesis of metal nanoparticles via microbes (bacteria, fungi, virus, yeast, algae etc.) has the potential to deliver clean manufacturing technology. Fungi are in the great use for the synthesis of nanoparticles and are more advantageous as compared with other microorganisms in several ways. Fungi grow in the form of a group of mycelia, which helps them to withstand flow pressure and agitation and various other conditions to which microbes are subjected to in a bioreactor, used for large-scale production. This review has its major focus on fungus Fusarium oxysporum, which is capable of synthesizing a large number of different types of nanoparticles such as titanium, magnesium, platinum, silver, gold, zirconium, and strontium, titania and silica oxide and many more. Biogenically synthesized nanoparticles are characterized by different techniques and exhibited biological activity. The fungi with metabolic capabilities can effectively synthesize a large number of nanoparticles both extracellularly and intracellularly. The biologically synthesized nanoparticles have wide ranges of applications especially in agricultural and medicinal industries.

Biogenic synthesis of silver nanoparticles using cyanobacterium Leptolyngbya sp. WUC 59 cell-free extract and their effects on bacterial growth and seed germination.

The biogenic synthesis of metal nanoparticles (NPs) is of great significance, as it renders clean, biocompatible, innocuous and worthwhile production. Here, we present a clean and sustainable route for the synthesis of silver nanoparticles (Ag NPs) using the cell-free aqueous extract of the cyanobacterium Leptolyngbya sp. WUC 59, isolated from polluted water and identified using a polyphasic approach. The conformation and characterisation of the as-synthesized biogenic Ag NPs was carried out using various sophisticated techniques like UV-visible (UV-Vis), X-ray diffraction (XRD), Fourier transform infrared (FTIR), energy dispersive X-ray spectroscopy (EDS) and high-resolution transmission electron microscopy (HRTEM). The sharp colour change and emergence of a characteristic peak at 430 nm in the UV-Vis spectrum confirm the formation of the Ag NPs. The morphological and physical appearance indicated that the synthesized Ag NPs are crystalline with a typical size of 20–35 nm. Furthermore, the bio-reduced nanoparticles were explored for their antibacterial activity against Bacillus subtilis and Escherichia coli bacteria, seed germination effects and early seedling growth of wheat (Triticum aestivum L.). The Ag NPs significantly suppressed the growth of both Bacillus subtilis and Escherichia coli bacteria with the treatment of 10 mg L−1 concentration within the initial 3 hours. The lower concentration (25 mg L−1) of the synthesized Ag NPs significantly enhanced the seed germination and early seedling growth of wheat in comparison to the control on the 4th and 8th day. The present investigations show that the use of the cyanobacterium Leptolyngbya sp. WUC 59 provides a simple, cost-effective and eco-friendly tool for the synthesis of Ag NPs. Moreover, it could have great potential for use as an alternative to chemical-based bactericides not only in pharmaceutical industries, but also to control bacterial diseases in agricultural crops.

Biogenic Synthesis of Zinc Oxide (ZnO) Nanoparticles Using a Fungus (Aspargillus niger) and Their Characterization

Nanoparticles are ultrafine structures with dimensions less than 100 nm. Nanoparticles have diverse applications. There are three important methods of fabrication of nanoparticles namely physical, chemical and biological methods. Physical method is a top down strategy for the fabrication of nanoparticles. It is energy intensive and time consuming. A chemical method is simple, but is expensive and requires expensive chemicals with high purity and also involves hazards of contaminations. Biological synthesis is very simple, cheap and environment friendly, requiring no expensive chemicals, temperature and is time saving. Plants and microorganisms are commonly used in this method. These are available everywhere. In the present work we synthesized Zinc Oxide (ZnO) nanoparticles by biological method using Aspargillus niger and zinc chloride (ZnCl2) as precursors. Biogenic synthesis of metallic nanoparticles by fungi is a safe and economical process because of formation of stable and small sized nanoparticles. Fungal biomass secretes proteins which act as reducing and stabilizing agents. The synthesized nanoparticles were characterized by XRD (X-Ray Diffraction), SEM (Scanning Electron Microscopy), UV-Vis (Ultraviolet, Visible) and EDX (Energy Dispersive X-Ray) techniques. Their size was in nm range and morphology of synthesized ZnO NPs was hexagonal. The ZnO nanoparticles are one of the most versatile materials and are used in cosmetics and in Bioenergy production, as a catalyst and as antibacterial material.

Biogenic synthesis of gold nanoparticles from Halymenia dilatata for pharmaceutical applications: Antioxidant, anti-cancer and antibacterial activities

Abstract Biogenic synthesis of metal nanoparticles using seaweeds is more biocompatible and more valuable for biomedical applications. In this study, gold nanoparticles were synthesized from the aqueous extract of Halymenia dilatata (Hd-AuNPs) and characterized by various spectral and microscopic techniques. The Hd-AuNPs exhibit a surface plasmon resonance peak at 529 nm. FT-IR results confirm the presence of polysaccharides and pigments in the extract, which reduce Au3+ to Au0. Microscopic analysis confirmed that Hd-AuNPs were triangular and spherical in shape with an average size of 16 nm. In terms of potential antioxidant properties, DPPH radical scavenging (13.7 ± 0.40 to 58.7 ± 0.85%), reducing power (16.3 ± 0.63 to 62.4 ± 0.60%) and total antioxidant (12.4 ± 0.50 to 56.6 ± 0.74%) activities were reasonably high in Hd-AuNPs compared with the extract alone. In the cytotoxicity assay, the IC50 of Hd-AuNPs was 22.62 μg/ml against HT-29 cancer cells. Similarly, in the antibacterial assay, the highest zone of inhibition (21 mm) was recorded at 100 μg/ml against Aeromonas hydrophila and the activity was proportionate to the concentration of Hd-AuNPs. In addition, the biosynthesis of Hd-AuNPs was non-toxic to zebrafish embryo. Overall, synthesized Hd-AuNPs exhibit commendable antioxidant, anti-cancer and antibacterial activities.