Extracellular biosynthesis of silver nanoparticles using the fungus Fusarium oxysporum

Green Synthesis of Silver Nanoparticles Using Bellevalia Flexuosa Leaves Extract

Silver nanoparticles (AgNPs) have broad biocidal activities, and are widely employed as an active ingredient in antiseptic, anti-viral, and anti-inflammatory preparations. Green-synthesizing AgNPs would be a rapid, cheap, and environmentally friendly method of synthesis. The methanolic extract of the leaves of Bellevalia flexuosa Boiss. (Asparagaceae) was used for the green synthesis of the AgNPs. The effects of the pH and the concentration of silver nitrate (AgNO3) on the synthesis of the AgNPs were investigated. The AgNPs produced above pH 10, and 1 mM of AgNO3 resulted in lower hydrodynamic diameters. Ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction proved the formation of the AgNPs, with a face-centered, cubed geometry. Scanning electron microscopy images showed colloidal and well-dispersed nanoparticles. In addition, the antibacterial activities of the prepared AgNPs were assessed by optical densities (ODs) against Gram-positive bacteria (Enterococcus faecalis and Staphylococcus epidermidis) and Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, and Salmonella enterica). The broths of Gram-negative and Gram-positive bacteria that contained AgNPs, showed lower OD values compared to the controls. In conclusion, AgNPs were prepared using B. flexuosa methanolic extract, and showed antibacterial activity against the tested bacterial strains.

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

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

Microbased biorefinery for gold nanoparticle production: recent advancements, applications and future aspects

Multifaceted utility of nanomaterials is indispensable to meet the environmental challenges across the globe. Nanomaterials substantially contribute in delineating the rapidly advancing field of nanotechnology. Recently, primary emphasis has been laid down on augmenting the biological methodologies for the synthesis of nanomaterials. In this aspect, green nanotechnology has revolutionized the entire process of nanosynthesis. Essentially biofabrication of nanoparticles have long-range applications, primarily in the field of medical applications such as drug delivery, cancer diagnostics and genetic engineering processes. Biocompatible and stable nanoparticles synthesized from biological source can be an effective approach against the chemically synthesized owing to their non-expensive and eco-friendly attributes. Biological systems including bacteria, yeasts, fungi and plants have already been exploited in the field of nanotechnology. Use of fungi seems to be a very effective and economical approach for the synthesis of gold nanoparticles. Gold nanoparticles possess anti-oxidation activity, are highly stable and biocompatible in nature. Fungi-mediated nanoparticle biosynthesis is more advantageous as compared to bacterial synthesis. Fungi secrete large amounts of enzymes, whereas the enzyme secretion of yeasts is weak. Here, we have reported the recent advancements and future implications in the field of gold nanoparticle production and applications.

Optimization of Synthesis of Silver Nanoparticles Conjugated with Lepechinia meyenii (Salvia) Using Plackett-Burman Design and Response Surface Methodology—Preliminary Antibacterial Activity

In the present investigation, an ethanolic fraction (EF) of Lepechinia meyenii (salvia) was prepared and fractionated by gradient column chromatography, and the main secondary metabolites present in the EF were identified by HPLC-MS. Silver nanoparticles (AgNPs) were synthesized and conjugated with the EF of Lepechinia meyenii (salvia). The AgNPs synthesis was optimized using Plackett-Burman design and response surface methodology (RSM), considering the following independent variables: stirring speed, synthesis pH, synthesis time, synthesis temperature and EF volume. The AgNPs synthesized under the optimized conditions were characterized by UV visible spectroscopy (UV-VIS), Fourier Transform Infrared Spectroscopy (FT-IR), Dynamic Light Scattering (DLS) and Scanning Transmission Electron Microscopy (STEM). The antibacterial activity of the AgNPs against Staphylococcus aureus (ATCC® 25923) was evaluated. The following flavonoids were identified: rosmarinic acid, diosmin and hesperetin-7-O-rutinoside. The optimized conditions for the synthesis of nanoparticles were pH 9.45, temperature 49.8 °C, volume of ethanolic fraction 152.6 µL and a reaction time of 213.2 min. The obtained AgNPs exhibited an average size of 43.71 nm and a resonance plasmon of 410–420 nm. Using FT-IR spectroscopy, the disappearance of the peaks between 626.50 and 1379.54 cm−1 was evident with the AgNPs, which would indicate the participation of these functional groups in the synthesis and protection of the nanoparticles. A hydrodynamic size of 47.6 nm was obtained by DLS, while a size of 40–60 nm was determined by STEM. The synthesized AgNPs conjugated with the EF showed a higher antibacterial activity than the EF alone. These results demonstrate that the AgNPs synthesized under optimized conditions conjugated with the EF of the Lepechinia meyenii (salvia) presented an increased antibacterial activity.

Nanotechnological interventions of the microbiome as a next-generation antimicrobial therapy

The rise of antimicrobial resistance (AMR) impacts public health due to the diminished potency of existing antibiotics. The microbiome plays an important role in the host's immune system activity and shows the history of exposure to antimicrobials and its manipulation in combating antimicrobial resistance. Advancements in gene technologies, DNA sequencing, and computational biology have emerged as powerful platforms to better understand the relationship between animals and microorganisms (MOs). The past few years have witnessed an increase in the use of nanotechnology, both in industry and in academia, as tools to tackle antimicrobial resistance. New strategies of microbiome manipulation have been developed, such as the use of prebiotics, probiotics, peptides, antibodies, an appropriate diet, phage therapy, and the use of various nanotechnological techniques. Owing to the research outcomes, targeted delivery of antimicrobials with some modifications with nanoparticles can lead to the destruction of resistant microbial cells. In addition, nanoparticles have been studied for their potential antimicrobial effects both in vitro and in vivo. In this review, we highlight key opportunistic areas for applying nanotechnologies with the aim of manipulating the microbiome for the treatment of antimicrobial resistance. Besides providing a detailed review on various nanomaterials, technologies, opportunities, technical needs, and potential approaches for the manipulation of the microbiome to address these challenges, we discuss future challenges and our perspective.

Metallic and Metal Oxides Nanoparticles for Sensing Food Pathogens—An Overview of Recent Findings and Future Prospects

Nowadays, special importance is given to quality control and food safety. Food quality currently creates significant problems for the industry and implicitly for consumers and society. The effects materialize in economic losses, alterations of the quality and organoleptic properties of the commercial products, and, last but not least, they constitute risk factors for the consumer’s health. In this context, the development of analytical systems for the rapid determination of the sanitary quality of food products by detecting possible pathogenic microorganisms (such as Escherichia coli or Salmonella due to the important digestive disorders that they can cause in many consumers) is of major importance. Using efficient and environmentally friendly detection systems for identification of various pathogens that modify food matrices and turn them into food waste faster will also improve agri-food quality throughout the food chain. This paper reviews the use of metal nanoparticles used to obtain bio nanosensors for the purpose mentioned above. Metallic nanoparticles (Au, Ag, etc.) and their oxides can be synthesized by several methods, such as chemical, physical, physico-chemical, and biological, each bringing advantages and disadvantages in their use for developing nanosensors. In the “green chemistry” approach, a particular importance is given to the metal nanoparticles obtained by phytosynthesis. This method can lead to the development of good quality nanoparticles, at the same time being able to use secondary metabolites from vegetal wastes, as such providing a circular economy character. Considering these aspects, the use of phytosynthesized nanoparticles in other biosensing applications is also presented as a glimpse of their potential, which should be further explored.

Biologically Derived Gold Nanoparticles and Their Applications

Nanotechnology is a rapidly evolving discipline as it has a wide variety of applications in several fields. They have been synthesized in a variety of ways. Traditional processes such as chemical and physical synthesis have limits, whether in the form of chemical contamination during synthesis operations or in subsequent applications and usage of more energy. Over the last decade, research has focused on establishing easy, nontoxic, clean, cost-effective, and environmentally friendly techniques for nanoparticle production. To achieve this goal, biological synthesis was created to close this gap. Biosynthesis of nanoparticles is a one-step process, and it is ecofriendly in nature. The metabolic activities of biological agents convert dissolved metal ions into nanometals. For biosynthesis of metal nanoparticles, various biological agents like plants, fungus, and bacteria are utilized. In this review paper, the aim is to provide a summary of contemporary research on the biosynthesis of gold nanoparticles and their applications in various domains have been discussed.

Microenvironmental Behaviour of Nanotheranostic Systems for Controlled Oxidative Stress and Cancer Treatment

The development of smart, efficient and multifunctional material systems for diseases treatment are imperative to meet current and future health challenges. Nanomaterials with theranostic properties have offered a cost effective and efficient solution for disease treatment, particularly, metal/oxide based nanotheranostic systems already offering therapeutic and imaging capabilities for cancer treatment. Nanoparticles can selectively generate/scavenge ROS through intrinsic or external stimuli to augment/diminish oxidative stress. An efficient treatment requires higher oxidative stress/toxicity in malignant disease, with a minimal level in surrounding normal cells. The size, shape and surface properties of nanoparticles are critical parameters for achieving a theranostic function in the microenvironment. In the last decade, different strategies for the synthesis of biocompatible theranostic nanostructures have been introduced. The exhibition of therapeutics properties such as selective reactive oxygen species (ROS) scavenging, hyperthermia, antibacterial, antiviral, and imaging capabilities such as MRI, CT and fluorescence activity have been reported in a variety of developed nanosystems to combat cancer, neurodegenerative and emerging infectious diseases. In this review article, theranostic in vitro behaviour in relation to the size, shape and synthesis methods of widely researched and developed nanosystems (Au, Ag, MnOx, iron oxide, maghemite quantum flakes, La2O3-x, TaOx, cerium nanodots, ITO, MgO1-x) are presented. In particular, ROS-based properties of the nanostructures in the microenvironment for cancer therapy are discussed. The provided overview of the biological behaviour of reported metal-based nanostructures will help to conceptualise novel designs and synthesis strategies for the development of advanced nanotheranostic systems.

Facile synthesis of nanomaterials as nanofertilizers: a novel way for sustainable crop production

Nutrient fertilization plays a major role in improving crop productivity and maintaining soil fertility. In the last few decades, the productivity of current agricultural practices highly depends on the use of chemical fertilizers. Major drawback of traditional fertilizers is their low crop nutrient use efficiency and high loss into water. Nanomaterial in agriculture is a multipurpose tool for increasing growth, development, and yield of plants. Nanotechnology facilitates the amplifying of agriculture production by reducing relevant losses and improving the input efficiency. Nanotechnology has emerged as an attractive field of research and has various agriculture applications, especially the use of nano-agrochemicals to increase nutrient use efficiency and agricultural yield. Nanofertilizers are more effective as compared to chemical fertilizers due to their cost-efficient, eco-friendly, non-toxic, and more stable in nature. Overall, this chapter focuses on synthesis of nanofertilizers through physical, chemical, and biological methods. This chapter will also explore the use of nano-enabled fertilizers to enhance the nutrient use efficiency for sustainable crop production, and global food safety.

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

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

Cyanobacteria: miniature factories for green synthesis of metallic nanomaterials: a review

Nanotechnology is one of the most promising and advanced disciplines of science that deals with synthesis, characterization and applications of different types of Nanomaterials (NMs) viz. nanospheres, nanoparticles, nanotubes, nanorods, nanowires, nanocomposites, nanoalloys, carbon dots and quantum dots. These nanosized materials exhibit different physicochemical characteristics and act as a whole unit during its transport. The unique characteristics and vast applications of NMs in diverse fields viz. electronics, agriculture, biology and medicine have created huge demand of different type of NMs. Conventionally physical and chemical methods were adopted to manufacture NMs which are expensive and end up with hazardous by-products. Therefore, green synthesis exploiting biological resources viz. algae, bacteria, fungi and plants emerged as a better and promising alternative due to its cost effective and ecofriendly approach and referred as nanobiotechnology. Among various living organisms, cyanobacteria have proved one of the most favourable bioresources for NMs biosynthesis due to their survival in diverse econiches including metal and metalloid contaminated sites and capability to withstand high levels of metals. Biosynthesis of metallic NMs is accomplished through bioreduction of respective metal salts by various capping agents viz. alkaloids, pigments, polysaccharides, steroids, enzymes and peptides present in the biological systems. Advancement in the field of Nanobiotechnology has produced large number of diverse NMs from cyanobacteria which have been used as antimicrobial agents against Gram positive and negative human pathogens, anticancer agents, luminescent nanoprobes for imaging of cells, antifungal agents against plant pathogens, nanocatalyst and semiconductor quantum dots in industries and in bioremediation in toxic pollutant dyes. In the present communication, we have reviewed cyanobacteria mediated biosynthesis of NMs and their applications in various fields.

Comparative evaluation of biomedical and phytochemical applications of zinc nanoparticles by using Fagonia cretica extracts

The use of the green approach for nanoparticle synthesis yielded noticeable concern due to its eco-friendliness, cost-effectiveness, and reduced production of toxic chemicals. The current study was designed to formulate Zinc oxide nanoparticles (ZnO NPs) by using Fagonia cretica extracts, evaluating its phytochemical content, and different biological activities. Four different solvents; methanol (MeOH), n-Hexane (n–H), aqueous (Aq), and ethyl acetate (EA), had been utilized in the extracting method. ZnO NPs were successfully synthesized and characterized by UV–vis spectroscopy and scanning electron microscopy (SEM). The UV–vis spectra showed absorbance peaks between 350–400 nm range and SEM analysis revealed spherical morphology with particle sizes ranging from 65–80 nm. In phytochemical analysis, crude extracts exhibited the highest phytochemical content as they contain enriched secondary metabolites. n-hexane extract showed the highest phenolic contents while aqueous extracts showed the highest flavonoid content. Maximum free radicle scavenging activity was observed in NPs synthesized from ethyl-acetate extract with an IC₅₀ value of 35.10 µg/ml. Significant antibacterial activity was exhibited by NPs polar solvents against K. pneumonae, E. coli, and B. subtilis. Polar solvents showed considerable antifungal potential against A. flavus and F. solani. NPs synthesized from nH extract showed potential cytotoxic activity with an LC₅₀ value of 42.41 µg/ml against brine shrimps. A noteworthy antidiabetic activity was exhibited by nanoparticles synthesized from methanol extract i.e., 52.61 ± 0.36%. Significant bald zones were observed in nanoparticles synthesized from methanol extract rendering protein kinase inhibition. The present study highlights the significance of F. indica as a natural source for synthesizing functional nanoparticles with substantial antioxidant, antimicrobial, cytotoxic, protein kinase inhibitory, and antidiabetic properties.

Physiological Response of Saccharomyces cerevisiae to Silver Stress

Silver nanoparticle (AgNP) production and their use as antimicrobial agents is a current area of active research. Biosynthesis is the most sustainable production method, and fungi have become candidates of interest in AgNP production. However, investigations into the physiological responses of fungi due to silver exposure are scanty. This present work utilized two strains of Saccharomyces cerevisiae (one used in commercial fermentation and a naturally occurring strain) to determine the physiological consequences of their transient exposure to AgNO₃. The assessments were based on studies involving growth curves, minimal inhibitory concentration assays, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) imaging, and inductively coupled plasma optical emission spectroscopy (ICP-OES). Results indicated (a) the capability of S. cerevisiae to produce silver nanoparticles, even at elevated levels of exposure; (b) strain origin had no significant impact on S. cerevisiae physiological response to AgNO₃; and (c) coexposure to copper and silver significantly increased intracellular copper, silver, and calcium in treated yeast cells. In addition, electron microscopy and ICP-OES results revealed that both strains internalized silver after exposure, resulting in the shrunken and distorted physical appearance visible on SEM micrographs of treated cells. Though a promising candidate for AgNPs biosynthesis, this study analyzed the effects of transient silver exposure on S. cerevisiae growth physiology and morphology.

Chitosan Silver and Gold Nanoparticle Formation Using Endophytic Fungi as Powerful Antimicrobial and Anti-Biofilm Potentialities

Nanotechnology is emerging as a new technology with encouraging innovations. Global antibiotic use has grown enormously, with antibiotic resistance increasing by about 80 percent. In view of this alarming situation, intensive research has been carried out into biogenic nanoparticles and their antibacterial, antifungal, and antitumor activities. Many methods are available to enhance stability and dispersion via peroration of conjugate with a polymer, such as chitosan, and other bioactive natural products. Two marine fungi were isolated and identified as Aspergillus sp. and Alternaria sp. via sequencing of the 16S rRNA gene. In this work, these strains were used to form the conjugation of biogenic silver nanoparticles (AgNPs) from Aspergillus sp. Silv2 extract and gold nanoparticles (AuNPs) from Alternaria sp. Gol2 extracts with chitosan to prepare chitosan–AgNPs and chitosan–AuNP conjugates. A variety of imaging and analytical methods, such as UV–vis, X-ray powder diffraction (XRD), FTIR spectroscopy, transmission electron microscopy (TEM), and scanning electron microscopy (SEM) were utilized to characterize biogenic nanoparticles and conjugates. The biosynthesized Ag and Au nanoparticles along with the prepared conjugates were evaluated for their antimicrobial effects on Gram-negative and Gram-positive bacterial isolates, including Escherichia coli and Staphylococcus aureus. Both chitosan–AgNP and AuNP showed powerful antimicrobial activities compared to the control. On the other hand, chitosan–AgNP conjugation had better antibacterial ctivity than chitosan–AuNPs, which exhibited moderate activity against S. aureus and very low activity against E. coli. Furthermore, the antibiofilm potentials of the prepared conjugates were tested against four biofilm-forming bacteria, including P. aeruginosa, B. subtilis, E. coli, and S. aureus. The obtained results indicate that the chitosan–AgNP showed a promising anti-biofilm activities on all strains, especially S. aureus, while chitosan–AuNP conjugates showed moderate anti-biofilm against B. subtilis and weak activities against the other three strains. These results showed the superiority of chitosan–AgNP as a promising antibacterial as well as biofilm formation inhibitors.

Synthesis and characterization of nanoparticles from neem leaves and banana peels: a green prospect for dye degradation in wastewater

Nanoparticles have excellent catalytic, adsorptive, and reactive properties, which led to their application for wastewater treatment. The current study focuses on silver nanoparticle synthesis using neem leaf and banana peel extract and its application as an antimicrobial and dye degrading agent for wastewater treatment. The use of these extracts led to a rapid, simple, and environment-friendly method for the biosynthesis of silver nanoparticles (AgNPs). UV-Vis spectroscopy showed absorption bands at 473 and 423 nm for AgNPs synthesized from neem leaf and banana peel extracts, respectively. The AgNPs were further characterized using XRD, FTIR, ESEM, EDX, and DLS methods. XRD data confirmed the crystalline nature of the synthesized AgNPs. ESEM images revealed the synthesized nanoparticles were spherical. From DLS analysis the average diameter of the AgNPs was found to be 168.7 nm from banana peel and 206.4 nm from neem leaf extract. Antibacterial activity of synthesized nanoparticles at 0.025 mg/ml concentration was tested against Escherichia coli (E.coli), Bacillus subtilis (B.subtilis), Staphylococcus aureus (S.aureus), and Klebsiella sp. using disk diffusion method and the zone of inhibitions observed were 10-13, 3-4, 2-3, and 1-3 nm respectively. 99% degradation of model dye malachite green was observed using banana peels-derived nanoparticles at a concentration of 0.06 mg/ml within 4.5 h. This study provides an eco-friendly and economic approach to AgNP synthesis and its potential application in the removal of hazardous dye from wastewater.

Antibacterial activity of biosynthesized silver nanoparticles (AgNps) against Pectobacterium carotovorum

In a bioprospecting study of paramo soils cultivated with potato (Solanum tuberosum), 50 fungal isolates were obtained and evaluated for their nitrate reductase (NR) activity, given the role played by this enzyme in the biosynthesis of silver nanoparticles (AgNps). Five isolates strain with high NR activity belonging to Penicillium simplicissimum, Aspergillus niger, and Fusarium oxysporum species were selected, verifying the presence of the NR enzyme in their enzymatic extract. Later, these strains showed the ability to biosynthesize AgNps with distorted spherical shapes and sizes ranging from 15 to 45 nm. Subsequently, an antibiosis test was carried out by the agar diffusion method using glass fiber disks against the phytopathogenic agent Pectobacterium carotovorum, finding halos of inhibition of bacterial growth up to 15.3 mm using a 100 ppm solution of the AgNps obtained from F. oxysporum. These results contribute to generating the basis of a new alternative for the control of this phytopathogenic agent of potato, challenging to manage by traditional methods and of relevance at the post-harvest level.

Enhanced degradation capability of white-rot fungi after short-term pre-exposure to silver ion: Performance and selectively antimicrobial mechanisms

Azo dyes in wastewater have great threats to environment and human health. White-rot fungi (WRF) have broad-spectrum potential for such refractory organics bioremediation; however, their applications are largely restrained by the poor viability owning to microbial invasion under non-sterile conditions. In this study, short-term pre-exposure to silver ion (Ag⁺) was demonstrated to be a practical, economic, and green method to enhance the perdurability of azo dyes decoloration by WRF Phanerochaete chrysosporium under non-sterile conditions. In control (without Ag⁺ pre-exposure), decoloration deactivated since cycle 7 (<10%), whereas in Ag⁺ pre-exposure groups, the decoloration ratios remained 91.5%-94.7% after 7 cycles. Variations in decoloration-related extracellular lignin enzyme activities were consistent with the decoloration effectiveness. The enhanced decoloration capability in Ag⁺ pre-exposure groups under non-sterile conditions could be ascribed to the selectively antimicrobial action by Ag⁺. The released Ag⁺ from the self-assembled silver nanoparticles (AgNPs) could selectively "stimulate" the proliferation and viability of P. chrysosporium, and simultaneously inhibit the growths of invasive microorganisms. The pyrosequencing results indicated that genus Sphingomonas (24.1%-31.3%) was the main invasive bacteria in Ag⁺ pre-exposure groups after long-term operation owing to the AgNPs passivation. As control, the invasive fungi (Asterotremella humicola) and bacteria (Burkholderia spp.) occurred in control after short-term operation, and genus Burkholderia (74.9%) dominated after long-term operation, leading to decoloration deactivation. Overall, these findings offer a new insight into the bio-nano interactions between WRF and invasive microorganisms in response to Ag⁺ or biogenic AgNPs, and could extend WRF application perspective under non-sterile conditions in future.

Green Metallic Nanoparticles: Biosynthesis to Applications

Current advancements in nanotechnology and nanoscience have resulted in new nanomaterials, which may pose health and environmental risks. Furthermore, several researchers are working to optimize ecologically friendly procedures for creating metal and metal oxide nanoparticles. The primary goal is to decrease the adverse effects of synthetic processes, their accompanying chemicals, and the resulting complexes. Utilizing various biomaterials for nanoparticle preparation is a beneficial approach in green nanotechnology. Furthermore, using the biological qualities of nature through a variety of activities is an excellent way to achieve this goal. Algae, plants, bacteria, and fungus have been employed to make energy-efficient, low-cost, and nontoxic metallic nanoparticles in the last few decades. Despite the environmental advantages of using green chemistry-based biological synthesis over traditional methods as discussed in this article, there are some unresolved issues such as particle size and shape consistency, reproducibility of the synthesis process, and understanding of the mechanisms involved in producing metallic nanoparticles via biological entities. Consequently, there is a need for further research to analyze and comprehend the real biological synthesis-dependent processes. This is currently an untapped hot research topic that required more investment to properly leverage the green manufacturing of metallic nanoparticles through living entities. The review covers such green methods of synthesizing nanoparticles and their utilization in the scientific world.

Identification of heavy metal ions from aqueous environment through gold, Silver and Copper Nanoparticles: An excellent colorimetric approach

Heavy metal pollution has become a severe threat to human health and the environment for many years. Their extensive release can severely damage the environment and promote the generation of many harmful diseases of public health concerns. These toxic heavy metals can cause many health problems such as brain damage, kidney failure, immune system disorder, muscle weakness, paralysis of the limbs, cardio complaint, nervous system. For many years, researchers focus on developing specific reliable analytical methods for the determination of heavy metal ions and preventing their acute toxicity to a significant extent. The modern researchers intended to utilize efficient and discerning materials, e.g. nanomaterials, especially the metal nanoparticles to detect heavy metal ions from different real sources rapidly. The metal nanoparticles have been broadly utilized as a sensing material for the colorimetric detection of toxic metal ions. The metal nanoparticles such as Gold (Au), Silver (Ag), and Copper (Cu) exhibited localized plasmon surface resonance (LPSR) properties which adds an outstanding contribution to the colorimetric sensing field. Though, the stability of metal nanoparticles was major issue to be exploited colorimetric sensing of heavy emtal ions, but from last decade different capping and stabilizing agents such as amino acids, vitmains, acids and ploymers were used to functionalize the metal surface of metal nanoparticles. These capping agents prevent the agglomeration of nanoparticles and make them more active for prolong period of time. This review covers a comprehensive work carried out for colorimetric detection of heavy metals based on metal nanoparticles from the year 2014 to onwards.

Nematicidal activity of seaweed-synthesized silver nanoparticles and extracts against Meloidogyne incognita on tomato plants

The purpose of this study was to test the nematicidal activity of extracts of two marine algae (Colpomenia sinuosa and Corallina mediterranea) and their synthesized silver nanoparticles against root-knot nematodes (Meloidogyne incognita) that infest tomato plants. Scanning electron microscopy (SEM) revealed that nanoparticles had aggregated into anisotropic Ag particles, and transmission electron microscopy (TEM) revealed that the particle sizes were less than 40 nm. Fourier Transform Infrared Spectroscopy (FT-IR) analysis revealed that the obtained nanoparticles had a sharp absorbance between 440 and 4000 cm^-1, with 13 distinct peaks ranging from 474 to 3915 cm^-1. Methylene chloride extracts and nanoparticles synthesized from both algae species were used to treat M. incognita. C. sinuosa nanoparticles had the highest nematicidal activity of any treatment. Furthermore, and in contrast to other treatments, C. sinuosa nanoparticles reduced the number of nematode galls, egg-masses per root, and eggs/egg mass, while also improving plant growth parameters. C. sinuosa's methylene chloride extract was more active than C. mediterranea's, and the most effective eluent of this solvent was hexane: methylene chloride: ethyl acetate (1: 0.5: 0.5, v/v/v). When applied to M. incognita, the third fraction of this eluent was the most effective, resulting in 87.5% mortality after 12 h and 100% mortality after 24 and 72 h of exposure. The presence of seven bioactive constituents was discovered during the analysis of this fraction. In conclusion, the silver nanoparticles synthesized from C. sinuosa could be used as alternative chemical nematicides.

Biological silicon nanoparticles maximize the efficiency of nematicides against biotic stress induced by Meloidogyne incognita in eggplant

Nemours effective management tactics were used to reduce world crop losses caused by plant-parasitic nematodes. Nowadays the metallic nanoparticles are easily developed with desired size and shape. Nanoparticles (NPs) technology becomes a recognized need for researchers. Ecofriendly and biosafe SiNPs are developed from microorganisms. Recently, silicon nanoparticles (SiNPs) have gained novel pesticide properties against numerous agricultural pests. This study assessed the biosynthesis of SiNPs from Fusarium oxysporum SM5. The obtained SiNPs were spherical with a size of 45 nm and a negative charge of -25.65. The nematocidal effect of SiNPs against egg hatching and second-stage juveniles (J2) of root-knot nematode (RKN) (Meloidogyne incognita) was evaluated on eggplant,Solanum melongena L. plants. In vitro, all tested SiNPs concentrations significantly (p ≤ 0.05) inhibited the percentage of egg hatching at a different time of exposure than control. Meanwhile, after 72 h, the percent mortality of J2 ranged from 87.00 % to 98.50 %, with SiNPs (100 and 200 ppm). The combination between SiNPs and the half-recommended doses (0.5 RD) of commercial nematicides namely,  fenamiphos (Femax 40 % EC)R, nemathorin (Fosthiazate 10 % WG) R, and fosthiazate (krenkel 75 % EC) R confirmed the increase of egg hatching inhibition and J2 mortality after exposure to SiNPs (100 ppm) mixed with 0.5 RD of synthetic nematicides. The findings suggest that the combination between SiNPs, and 0.5 RD of nematicides reduced nematode reproduction, gall formation, egg masses on roots and final population of J2 in the soil. Therefore, improving the plant growth parameters by reducing the M. incognita population.

Activity of Fusarium oxysporum-Based Silver Nanoparticles on Candida spp. Oral Isolates

Candida spp. resistant to commercially available antifungals are often isolated from patients with oral candidiasis, a situation that points to the need for the development of new therapies. Thus, we evaluated the activity of Fusarium oxysporum-based silver nanoparticles (AgNPs) on Candida spp. isolated from denture stomatitis lesions. Candida isolates were molecularly identified and submitted to susceptibility assays using AgNPs and commercial fungicides. The interference on biofilm formation and the mechanisms of action of AgNPs on Candida spp. were also investigated. Scanning electron microscopy was used to evaluate the morphology of AgNP-treated Candida. Candida albicans was the most frequent species isolated from denture stomatitis cases. All Candida spp. were susceptible to AgNPs at low concentrations, except Candida parapsilosis. AgNPs caused surface damage, cell disruption, and biofilm formation inhibition. The ergosterol supplementation protected C. albicans against the AgNP action. AgNPs are effective against Candida spp. and can be faced as a promising new therapeutic agent against oral candidiasis.

Plumeria alba-Mediated Green Synthesis of Silver Nanoparticles Exhibits Antimicrobial Effect and Anti-Oncogenic Activity against Glioblastoma U118 MG Cancer Cell Line

Plumeria alba (P. alba) is a small laticiferous tree with promising medicinal properties. Green synthesis of nanoparticles is eco-friendly, cost-effective, and non-hazardous compared to chemical and physical synthesis methods. Current research aiming to synthesize silver nanoparticles (AgNPs) from the leaf extract of P. alba (P- AgNPs) has described its physiochemical and pharmacological properties in recognition of its therapeutic potential as an anticancer and antimicrobial agent. These biogenic synthesized P-AgNPs were physiochemically characterized by ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscope (TEM), atomic force microscopy (AFM), X-ray diffractometry (XRD), and zeta potential analyses. Antimicrobial activity was investigated against Escherichia coli, Pseudomonas aeruginosa, Enterobacter aerogenes, Enterococcus faecalis, Bacillus subtilis, Streptococcus pneumoniae, Candida albicans, and Candida glabrata. Anticancer activity against glioblasoma U118 MG cancer lines was investigated using an MTT assay, and apoptosis activity was determined by flow cytometry. UV–visible spectroscopic analysis portrayed surface plasmon resonance at 403 nm of synthesized P-AgNPs, and FTIR suggested the presence of amines, alkanes, and phenol molecules that could be involved in reduction and capping processes during AgNPs formation. Synthesized particles were spherical in shape and poly-dispersed with an average particle size of 26.43 nm and a poly-dispersity index (PDI) of 0.25 with a zeta potential value of −24.6 mV, ensuring their stability. The lattice plane values confirm the crystalline nature as identified by XRD. These P-AgNPs exhibited potential antimicrobial activity against selected human pathogenic microbes. Additionally, the in vitro MTT assay results show its effective anticancer activity against the glioma U118 MG cancer cell line with an IC50 value of 9.77 µg/mL AgNPs by initiating apoptosis as identified by a staining study with flow cytometric annexin V–fluorescein isothiocyanate (FITC) and propidium iodide (PI). Thus, P. alba AgNPs can be recommended for further pharmacological and other biological research. To conclude, the current investigation developed an eco-friendly AgNPs synthesis using P. alba leaf extract with potential cytotoxic and antibacterial capacity, which can therefore be recommended as a new strategy to treat different human diseases.

Microbial synthesis of gold nanoparticles and their application

BACKGROUND

Nanoparticles play a very important role in our daily lives and have a wide range of applications in agriculture and the field of biology such as antioxidants and antimicrobial compounds. Among them are gold nanoparticles (AuNPs) that are highly complex and widely used. In recent years gold nanoparticles have attracted much attention because of their optical properties, electronic, physicochemical and surface Plasmon resonance (SPR). Gold plated nanoparticles, similar to metal nanoparticles, have many unusual chemical and physical properties due to the effects of their quantum size and location, compared to other iron or metal atoms. Gold nanoparticles can be used in pharmaceutical products such as antimicrobial and anti-biofilm agents, targeted delivery of anti-cancer drugs, biosensors, biocatalysis, bioremediation modification of toxic chemicals exposing the soil and atmosphere, dye reduction etc. Yet such methods are expensive and out of harmony with nature. In that account the microbes mediated synthesis of gold nanoparticles changed rapidly recently when pure microbes are ac-friendly, non-toxic and bio compatible as physiological and chemical methods. This document aims to review the progress made in recent years with the fusion of gold nanoparticles. Microbial source includes bacteria, algae fungi. These works motivate the people for how to apply and synthesize of gold nanoparticles. This review also focuses on the process of classification of gold nanoparticles, structures and their use in the development of various requirements.

OBJECTIVE

The main goal is to study about the gold nanoparticles and their application in future.

METHODS

We study different research paper, review paper from "Google Scholar", "NCBI", "PubMed", "Science Direct" and then we making our review paper.

CONCLUSION

Metal nanoparticles are suitable for many emerging technologies. Understanding the microorganisms found in nature because the fusion of gold nanoparticles is required.

Role of Biosynthesized Ag-NPs Using Aspergillus niger (MK503444.1) in Antimicrobial, Anti-Cancer and Anti-Angiogenic Activities

Green synthesis of nanoparticles is regarded as a safe and non-toxic process over conventional synthesis. Owing to the medicinal value of biologically derived biomolecules and utilizing them in synergy with nanoscience to offer more accurate therapeutic options to various diseases is an emerging field. One such study we present here with highlights of the synthesis and efficacy of biogenic silver nanoparticles produced from the extract of Aspergillus niger SAP2211 (accession number: MK503444.1) as an antimicrobial, anti-cancerous and anti-angiogenic agent. The synthesized Ag-NPs were characterized following UV-vis, FTIR, XRD, SEM and TEM, and were found to possess bactericidal activity against the selected pathogenic microbes, such as Staphylococcus aureus, Escherichia coli, and Salmonella typhi. Further, we evaluated cytotoxicity effect of this biogenic Ag-NPs using MMT assay on normal cardio myoblast (H9C2) and cancerous human cervical carcinoma (HeLa) cells. Doxorubicin used as positive control. This Ag-NPs have shown trivial cytotoxicity at the IC50 concentration on normal cells (IC50 = 47.17 µg/ml) over the cancer cells (IC50 = 8.609 µg/ml) with nearly 7 fold difference, indicating it as a selective anti-cancerous agent in contrast to standard drug doxorubicin (IC50 = 6.338 µg/ml). Further in-vitro assessment of wound healing capability by scratch wound healing assay, invasion by transwell matrigel invasion assay, and apoptosis via DAPI and annexin V-FITC assays were studied in HeLa cells. Synthesized biogenic Ag-NPs have shown to be anti-angiogenic in nature, which was established by in-vivo chick chorioallantois membrane assay. Overall, in vitro studies revealed that biogenic Ag-NPs positively inhibited migration, invasion, and induced apoptosis, and in-vivo CAM assay revealed that intercapillary network was reduced and the angiogenesis was inhibited.

Synthesis, purification and characterization of Plectonema derived AgNPs with elucidation of the role of protein in nanoparticle stabilization

Driven by the need to biosynthesize alternate biomedical agents to prevent and treat infection, silver nanoparticles have surfaced as a promising avenue. Cyanobacteria-derived nanomaterial synthesis is of substantive interest as it offers an eco-friendly, cost-effective, sustainable, and biocompatible route for further development. In the present study optimal conditions for synthesis of silver nanoparticles (AgNPs) were 1 : 9 v/v [cell extract: AgNO3 (1 mM)], pH 7.4, and 30 °C reaction temperatures. Synthesis of nanoparticles was monitored by UV-vis spectrophotometry and the maximum absorbance was observed at a wavelength of 420 nm. SEM with EDX analysis confirmed 96.85% silver by weight which revealed the purity of AgNPs. TEM & XRD analysis exhibited a particle size of ∼12 nm with crystalline nature. FTIR analysis confirmed the presence of possible biomolecules involved in the synthesis and stabilization of AgNPs. Decapping of AgNPs followed by SDS-PAGE, LCMS and MALDI TOF analysis elucidates the proteinaceous nature of the capping and stabilizing agent. Cyanobacterial-derived capped AgNPs showed more cytotoxicicity towards a non-small cell lung cancer (A549) cell line, free radical scavenger and an antimicrobial than de-capped AgNPs. In addition they showed significant synergistic characteristics with antibiotics and fungicides. The test revealed that the capped AgNPs were biocompatible with good anti-inflammatory properties. The blend of antimicrobial and biocompatible properties, coupled with their intrinsic "green" and facile synthesis, made these biogenic nanoparticles particularly attractive for future applications in nanomedicine.

Green Synthesis of Stable Spherical Monodisperse Silver Nanoparticles Using a Cell-Free Extract of Trichoderma reesei

In the current study, a green method for the preparation of silver nanoparticles (AgNPs) is presented as an alternative to conventional chemical and physical approaches. A biomass of Trichoderma reesei (T. reesei) fungus was used as a green and renewable source of reductase enzymes and metabolites, which are capable of transforming Ag⁺ ions into AgNPs with a small size (mainly 2-6 nm) and narrow size distribution (2-25 nm). Moreover, extracellular biosynthesis was carried out with a cell-free water extract (CFE) of T. reesei, which allows for facile monitoring of the bioreduction process using UV-Vis spectroscopy and investigation of the effect of experimental conditions on the transformation of Ag⁺ ions into AgNPs, as well as the simple isolation of as-prepared AgNPs for the study of their size, morphology and antibacterial properties. In continuation to our previous results about the influence of media on T. reesei cultivation, the amount of biomass used for CFE preparation and the concentration of Ag⁺ ion solution, herein, we present the impact of temperature (4, 20, 30 and 40 °C), agitation and time duration on the biosynthesis of AgNPs and their properties. A high stability of AgNPs in aqueous colloids was observed and attributed to the capping effect of the biomolecules as shown by the zeta potential (-49.0/-51.4 mV) and confirmed by the hydrodynamic size of 190.8/116.8 nm of AgNPs.

A Review on Plants and Microorganisms Mediated Synthesis of Silver Nanoparticles, Role of Plants Metabolites and Applications

Silver nanoparticles are one of the most extensively studied nanomaterials due to their high stability and low chemical reactivity in comparison to other metals. They are commonly synthesized using toxic chemical reducing agents which reduce metal ions into uncharged nanoparticles. However, in the last few decades, several efforts were made to develop green synthesis methods to avoid the use of hazardous materials. The natural biomolecules found in plants such as proteins/enzymes, amino acids, polysaccharides, alkaloids, alcoholic compounds, and vitamins are responsible for the formation of silver nanoparticles. The green synthesis of silver nanoparticles is an eco-friendly approach, which should be further explored for the potential of different plants to synthesize nanoparticles. In the present review we describe the green synthesis of nanoparticles using plants, bacteria, and fungi and the role of plant metabolites in the synthesis process. Moreover, the present review also describes some applications of silver nanoparticles in different aspects such as antimicrobial, biomedicine, mosquito control, environment and wastewater treatment, agricultural, food safety, and food packaging.

Synthesis, Characterization and Biomedical Application of Silver Nanoparticles

Silver nanoparticles (AgNPs) have been employed in various fields of biotechnology due to their proven properties as an antibacterial, antiviral and antifungal agent. AgNPs are generally synthesized through chemical, physical and biological approaches involving a myriad of methods. As each approach confers unique advantages and challenges, a trends analysis of literature for the AgNPs synthesis using different types of synthesis were also reviewed through a bibliometric approach. A sum of 10,278 publications were analyzed on the annual numbers of publication relating to AgNPs and biological, chemical or physical synthesis from 2010 to 2020 using Microsoft Excel applied to the Scopus publication database. Furthermore, another bibliometric clustering and mapping software were used to study the occurrences of author keywords on the biomedical applications of biosynthesized AgNPs and a total collection of 224 documents were found, sourced from articles, reviews, book chapters, conference papers and reviews. AgNPs provides an excellent, dependable, and effective solution for seven major concerns: as antibacterial, antiviral, anticancer, bone healing, bone cement, dental applications and wound healing. In recent years, AgNPs have been employed in biomedical sector due to their antibacterial, antiviral and anticancer properties. This review discussed on the types of synthesis, how AgNPs are characterized and their applications in biomedical field.

Biofabrication of ZnO nanoparticles using Acacia arabica leaf extract and their antibiofilm and antioxidant potential against foodborne pathogens

Emergence of multidrug resistant pathogens is increasing globally at an alarming rate with a need to discover novel and effective methods to cope infections due to these pathogens. Green nanoparticles have gained attention to be used as efficient therapeutic agents because of their safety and reliability. In the present study, we prepared zinc oxide nanoparticles (ZnO NPs) from aqueous leaf extract of Acacia arabica. The nanoparticles produced were characterized through UV-Visible spectroscopy, scanning electron microscopy, and X-ray diffraction. In vitro antibacterial susceptibility testing against foodborne pathogens was done by agar well diffusion, growth kinetics and broth microdilution assays. Effect of ZnO NPs on biofilm formation (both qualitatively and quantitatively) and exopolysaccharide (EPS) production was also determined. Antioxidant potential of green synthesized nanoparticles was detected by DPPH radical scavenging assay. The cytotoxicity studies of nanoparticles were also performed against HeLa cell lines. The results revealed that diameter of zones of inhibition against foodborne pathogens was found to be 16-30 nm, whereas the values of MIC and MBC ranged between 31.25-62.5 μg/ml. Growth kinetics revealed nanoparticles bactericidal potential after 3 hours incubation at 2 × MIC for E. coli while for S. aureus and S. enterica reached after 2 hours of incubation at 2 × MIC, 4 × MIC, and 8 × MIC. 32.5-71.0% inhibition was observed for biofilm formation. Almost 50.6-65.1% (wet weight) and 44.6-57.8% (dry weight) of EPS production was decreased after treatment with sub-inhibitory concentrations of nanoparticles. Radical scavenging potential of nanoparticles increased in a dose dependent manner and value ranged from 19.25 to 73.15%. Whereas cytotoxicity studies revealed non-toxic nature of nanoparticles at the concentrations tested. The present study suggests that green synthesized ZnO NPs can substitute chemical drugs against antibiotic resistant foodborne pathogens.

Sonoproduction of nanobiomaterials - A critical review

Ultrasound (US) demonstrates remarkable potential in synthesising nanomaterials, particularly nanobiomaterials targeted towards biomedical applications. This review briefly introduces existing top-down and bottom-up approaches for nanomaterials synthesis and their corresponding synthesis mechanisms, followed by the expounding of US-driven nanomaterials synthesis. Subsequently, the pros and cons of sono-nanotechnology and its advances in the synthesis of nanobiomaterials are drawn based on recent works. US-synthesised nanobiomaterials have improved properties and performance over conventional synthesis methods and most essentially eliminate the need for harsh and expensive chemicals. The sonoproduction of different classes and types of nanobiomaterials such as metal and superparamagnetic nanoparticles (NPs), lipid- and carbohydrate-based NPs, protein microspheres, microgels and other nanocomposites are broadly categorised based on the physical and/or chemical effects induced by US. This review ends on a good note and recognises US-driven synthesis as a pragmatic solution to satisfy the growing demand for nanobiomaterials, nonetheless some technical challenges are highlighted.

Green synthesis of Silver nanoparticles using Streptomyces hirsutus strain SNPGA-8 and their characterization, antimicrobial activity, and anticancer activity against human lung carcinoma cell line A549

The current study described the systematic and detailed extracellular synthesis method of silver nanoparticles (AgNPs) using Streptomyces hirsutus strain SNPGA-8 by green synthesis method. The AgNPs were subjected for characterizations using UV-Vis, FTIR, TGA, TEM, EDX, XRD, and zeta-potential analyses. The antibacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Enterococcus faecalis, Escherichia coli, Candida albicans, Alternaria alternata, Candida glabrata and Fusarium oxysporum was determined by the agar well diffusion technique. The cytotoxicity of AgNPs against human lung cancer (A549) was studied by MTT and ROS assays and capping of proteins of AgNPs from SDS-PAGE. In the UV-Vis., absorption peak was found at 418 nm, FTIR analysis revealed the infrared bands of specific functional groups from 3273 cm-1 to 428 cm-1; TEM data confirmed the spherical shape, smallest size of particle as 18.99 nm, while EDX analysis confirmed the elemental composition of AgNPs with 22.24% Ag. The XRD pattern confirmed the nature of AgNPs as crystalline, and zeta potential peak was found at -24.6 mV indicating the higher stability. The AgNPs exhibited increased antimicrobial activity with increase in dosage volume and considerable MIC and MBC values against microbial pathogens. In the MTT cytotoxicity assay, the IC50 value of 31.41 μg/mL is obtained against A549 cell line, suggesting the potential of AgNPs to inhibit the tumour cells; and ROS assay displayed increased ROS production with increase in treatment time. Based on the results, it is evident that Streptomyces hirsutus strain SNPGA-8 AgNPs are potentially promising to be applied for biomedical uses.

Biogenic Synthesis of Silver Nanoparticles, Characterization and Their Applications—A Review

With the growing awareness for the need of sustainable environment, the importance of synthesizing and the application of green nanoparticles has gained special focus. Among various metal nanoparticles, silver nanoparticles (AgNPs) have gain significant attention. AgNPs are synthesized conventionally by physical and chemical methods using chemicals such as reducing agents, which are hazardous to environment due to their toxic properties, provoking a serious concern to create and develop environment friendly methods. Thus, biological alternatives are emerging to fill gaps, such as green syntheses that use biological molecules taken from plant sources in the form of extracts, which have shown to be superior to chemical and physical approaches. These biological molecules derived from plants are assembled in a highly regulated manner to make them suitable for metal nanoparticle synthesis. The current review outlines the wide plant diversity that may be used to prepare a rapid and single-step procedure with a green path over the traditional ones, as well as their antifungal activity.

Ovicidal, larvicidal and pupicidal efficacy of silver nanoparticles synthesized by Bacillus marisflavi against the chosen mosquito species

Microbial synthesis of silver nanoparticles is more advantageous and is eco-friendly to combat the various vectors that cause diseases in humans. Hence, in the present study a Bacillus strain is isolated from marine habitat and is evaluated for its ability to synthesize silver nanoparticles (AgNPs) and its efficacy evaluated against the immature stages of selected mosquito species. The effective candidate was confirmed to be Bacillus marisflavi after 16S rRNA sequencing. The synthesis of AgNPs was confirmed by UV-Vis spectrophotometer. Atomic Force Microscopic (AFM) analysis showed spherical nanoparticles. Size analysis using Scanning Electron Microscope (SEM) showed particles of nano size averaging 78.77 nm. The diameter of the particles analyzed by Dynamic Light Scattering (DLS) showed 101.6 nm with a poly-dispersive index of 0.3. Finally the elemental nature of the nanoparticles was identified by Fourier-transform infrared spectroscopy (FTIR). LC50 and LC90 values for the ovicidal, larvicidal and pupicidal efficacy of the AgNPs against the egg, larvae and pupae of Aedes aegypti, Culex quinquefasciatus and Anopheles stephensi respectively were evaluated. The present study revealed that the nanoparticles have an excellent toxic effect against the disease transmitting vector mosquitoes. Hence, the rapid synthesis of AgNPs would be an appropriate eco-friendly tool for biocontrol of vector mosquitoes.

Green Synthesis and Characterization of Copper Nanoparticles Using Fortunella margarita Leaves

The use of biomaterials in the synthesis of nanoparticles is one of the most up-to-date focuses in modern nanotechnologies and nanosciences. More and more research on green methods of producing metal oxide nanoparticles (NP) is taking place, with the goal to overcome the possible dangers of toxic chemicals for a safe and innocuous environment. In this study, we synthesized copper nanoparticles (CuNPs) using Fortunella margarita leaves' extract, which reflects its novelty in the field of nanosciences. The visual observation of a color change from dark green to bluish green clearly shows the instant and spontaneous formation of CuNPs when the phytochemicals of F. margarita come in contact with Cu+2 ions. The synthesis of CuNPs was carried out at different conditions, including pH, temperature, concentration ratio and time, and were characterized with UV-Vis absorption spectra, scanning electron microscope (SEM) and X-ray diffraction (XRD). The UV-Vis analysis reveals the surface plasmon resonance property (SPR) of CuNPs, showing a characteristic absorption peak at 679 nm, while SEM reveals the spherical but agglomerated shape of CuNPs of the size within the range of 51.26-56.66 nm.

Biosynthesis of silver nanoparticles using endophytic Fusarium oxysporum strain NFW16 and their in vitro antibacterial potential

Nanotechnology has provided a platform for altering, modifying, and developing metal properties to nanoparticles with promising applications. This study aimed to produce functionalized and biocompatible silver nanoparticles (AgNPs) using cellular extracts of endophytic Fusarium oxysporum-NFW16 isolated from Taxus fauna and evaluate its antibacterial potential. Under optimized reaction conditions, well-dispersed and extremely stable AgNPs were synthesized in 1 hr. AgNPs were characterized through UV-visible spectrophotometry (at 423 nm), and scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The obtained AgNPs were spherical, monodispersed, and size was ~30-36.1 nm. Strong peaks of XRD (311), (220), (200), and (111) matched to silver plane's diffraction facets. FTIR spectra at 1,650, 2,950, and 1,400 cm^-1 confirmed the capping of AgNPs with phenolic compounds and compounds having primary amines. The AgNPs showed 100 μg/ml of minimum inhibitory concentration against methicillin-resistant Staphylococcus aureus (MRSA). In addition, AgNPs showed a synergistic effect with both vancomycin and ciprofloxacin against MRSA (25%), Pseudomonas aeruginosa (50%), and pus isolated Escherichia coli (50%). Moreover, AgNPs impregnated cotton and bandage showed in vitro antibacterial potential against American Type Culture Collection and skin-associated clinical pathogenic bacteria. Findings showed that endophytic fungi are the potential source for AgNPs synthesis that are effective against multidrug-resistant bacteria and the development of antimicrobial textile finishes.

Nanotechnology as a Novel Approach in Combating Microbes Providing an Alternative to Antibiotics

The emergence of infectious diseases promises to be one of the leading mortality factors in the healthcare sector. Although several drugs are available on the market, newly found microorganisms carrying multidrug resistance (MDR) against which existing drugs cannot function effectively, giving rise to escalated antibiotic dosage therapies and the need to develop novel drugs, which require time, money, and manpower. Thus, the exploitation of antimicrobials has led to the production of MDR bacteria, and their prevalence and growth are a major concern. Novel approaches to prevent antimicrobial drug resistance are in practice. Nanotechnology-based innovation provides physicians and patients the opportunity to overcome the crisis of drug resistance. Nanoparticles have promising potential in the healthcare sector. Recently, nanoparticles have been designed to address pathogenic microorganisms. A multitude of processes that can vary with various traits, including size, morphology, electrical charge, and surface coatings, allow researchers to develop novel composite antimicrobial substances for use in different applications performing antimicrobial activities. The antimicrobial activity of inorganic and carbon-based nanoparticles can be applied to various research, medical, and industrial uses in the future and offer a solution to the crisis of antimicrobial resistance to traditional approaches. Metal-based nanoparticles have also been extensively studied for many biomedical applications. In addition to reduced size and selectivity for bacteria, metal-based nanoparticles have proven effective against pathogens listed as a priority, according to the World Health Organization (WHO). Moreover, antimicrobial studies of nanoparticles were carried out not only in vitro but in vivo as well in order to investigate their efficacy. In addition, nanomaterials provide numerous opportunities for infection prevention, diagnosis, treatment, and biofilm control. This study emphasizes the antimicrobial effects of nanoparticles and contrasts nanoparticles' with antibiotics' role in the fight against pathogenic microorganisms. Future prospects revolve around developing new strategies and products to prevent, control, and treat microbial infections in humans and other animals, including viral infections seen in the current pandemic scenarios.

Bionanofactories for Green Synthesis of Silver Nanoparticles: Toward Antimicrobial Applications

Among the various types of nanoparticles and their strategy for synthesis, the green synthesis of silver nanoparticles has gained much attention in the biomedical, cellular imaging, cosmetics, drug delivery, food, and agrochemical industries due to their unique physicochemical and biological properties. The green synthesis strategies incorporate the use of plant extracts, living organisms, or biomolecules as bioreducing and biocapping agents, also known as bionanofactories for the synthesis of nanoparticles. The use of green chemistry is ecofriendly, biocompatible, nontoxic, and cost-effective. We shed light on the recent advances in green synthesis and physicochemical properties of green silver nanoparticles by considering the outcomes from recent studies applying SEM, TEM, AFM, UV/Vis spectrophotometry, FTIR, and XRD techniques. Furthermore, we cover the antibacterial, antifungal, and antiparasitic activities of silver nanoparticles.

Fungi as veritable tool in current advances in nanobiotechnology

Fungi have great prospects for synthesis, applications and developing new products in nanotechnology. In recent times, fungi use in nanotechnology is gaining more attention because of the ecological friendly state of their metabolite-mediated nanoparticles, their safety, amenability and applications in diverse fields. The diversity of the metabolites such as enzymes, polysaccharide, polypeptide, protein and other macro-molecules has made fungi a veritable tool for nanoparticles synthesis. Mechanism of fungal nano-biosynthesis from the molecular perspective has been extensively studied through various investigations on its green synthesized metal nanoparticles. Fungal nanobiotechnology has been applied in agricultural, medical and industrial sectors for goods and services improvement and delivery to mankind. Agriculturally, it has found applications in plant disease management and production of environmentally friendly, non-toxic insecticides, fungicides to enhance agricultural production in general. Medically, diagnosis and treatment of diseases, especially of microbial origin have been improved with fungal nanoparticles through more efficient drug delivery systems with great benefits to pharmaceutical industries. This review therefore explored fungal nanobiotechnology; mechanism of synthesis, characterization and potential applications in various fields of human endeavours for goods and services delivery.

Environmental photochemistry in Solanum trilobatum mediated plasmonic nanoparticles as a probe for the detection of Cd2+ ions in water

Nowadays world deals with a lot of environmental troubles out of which water pollution is very dangerous. Water gets contaminated by heavy metal ions is a universal problem which needs suitable consideration to keep up the quality of the water. It will be advantageous that an easy device can be detecting the concentration of heavy metal ions in water. Here, a contaminant, cadmium from industrial affluent into water is considered and focused. Gold nanoparticles (AuNPs) have been synthesized by Solanum trilobatum leaf extract and its applications of antifungal and sensing activity was reported here. The influences of different concentration of these reducing agent on the synthesis of AuNPs (G5 and G10) have been evaluated. The structural, optical, vibrational, morphological and compositional properties of the AuNPs were studied through XRD, UV-vis spectra, FTIR, HRTEM and EDAX analysis. The optical studies showed surface plasmon absorbance peak at 526 nm. It shows that the absorbance of the peak becomes narrow with a higher concentration of leaf extract. XRD results showed the average size of the AuNPs was 8 nm. It also confirmed the high crystallinity of nanoparticles. FTIR exposes that amine and carboxyl groups may be involved in the stabilization and reduction mechanism. TEM pictures of both G10 and G5 demonstrate merely spherical nanoparticles. This morphology control is taken place owing to the adsorbed amine and carboxyl groups onto the gold nanoparticles cap the particles and improve the stability. The presence of gold elements in the sample was identified with the help of EDAX. The sensitivity of the system towards various Cd²⁺ concentrations was measured as 0.058/mM for G5 and 0.095/mM for G10. The prepared nanoparticles produced highest zone of inhibition (ZOI) of 17.5 mm and 19 mm against human being pathogenic fungi Aspergillus Flavus and Candida albicans respectively. Here, small sized spherical nanoparticles showed good antifungal activity.