Green Synthesis of Gold and Silver Nanoparticles from Plant Extracts and Their Possible Applications as Antimicrobial Agents in the Agricultural Area

Prospects and challenges of nanopesticides in advancing pest management for sustainable agricultural and environmental service

The expanding global population and the use of conventional agrochemical pesticides have led to the loss of crop yield and food shortages. Excessive pesticide used in agriculture risks life forms by contaminating soil and water resources, necessitating the use of nano agrochemicals. This article focuses on synthesis moiety and use of nanopesticides for enhanced stability, controlled release mechanisms, improved efficacy, and reduced pesticide residue levels. The current literature survey offered regulatory frameworks for commercial deployment of nanopesticides and evaluated societal and environmental impacts. Various physicochemical and biological processes, especially microorganisms and advanced oxidation techniques are important in treating pesticide residues through degradation mechanisms. Agricultural waste could be converted into nanofibers for sustainable composites production, new nanocatalysts, such as N-doped TiO2 and bimetallic nanoparticles for advancing pesticide degradation. Microbial and enzyme methods have been listed as emerging nanobiotechnology tools in achieving a significant reduction of chlorpyrifos and dimethomorph for the management of pesticide residues in agriculture. Moreover, cutting-edge biotechnological alternatives to conventional pesticides are advocated for promoting a transition towards more sustainable pest control methodologies. Application of nanopesticides could be critical in addressing environmental concern due to its increased mobility, prolonged persistence and ecosystem toxicity. Green synthesis of nanopesticides offers solutions to environmental risks associated and using genetic engineering techniques may induce pest and disease resistance for agricultural sustainability. Production of nanopesticides from biological sources is necessary to develop and implement comprehensive strategies to uphold agricultural productivity while safeguarding environmental integrity.

Aflatoxins in Peanut (Arachis hypogaea): Prevalence, Global Health Concern, and Management from an Innovative Nanotechnology Approach: A Mechanistic Repertoire and Future Direction

Arachis hypogaea is the most significant oilseed nutritious legume crop in agricultural trade across the world. It is recognized as a valued crop for its contributions to nourishing food, as a cooking oil, and for meeting the protein needs of people who are unable to afford animal protein. Currently, its production, marketability, and consumption are hindered because of Aspergillus species infection that consequently contaminates the kernels with aflatoxins. Regarding health concerns, humans and animals are affected by acute and chronic aflatoxin toxicity and millions of people are at high risk of chronic levels. Most methods used to store peanuts are traditional and serve effectively for short-term storage. Now the question for long-term storage has been raised, and this promptly finds potential approaches to the issue. It is imperative to reduce the aflatoxin levels in peanuts to a permissible level by introducing detoxifying innovations. Most of the detoxification reports mention physical, chemical, and biological techniques. However, many current approaches are impractical because of time consumption, loss of nutritional quality, or weak detoxifying efficiency. Therefore, it is crucial to investigate practical, economical, and green methods to control Aspergillus flavus that address current global food security problems. Herein, a green and economically revolutionary way is a nanotechnology that has demonstrated its potential to connect farmers to markets, elevate international marketability, improve human and animal health conditions, and enhance food quality and safety by the management of fungal diseases. Due to the antimicrobial potential of nanoparticles, they act as nanofungicides and have an incredible role in the control of aflatoxins. Nanoparticles have ultrasmall sizes and therefore penetrate the fungal body and invade the pathogen machinery, leading to fungal cell death by ROS production, mutation in DNA, disruption of organelles, and membrane leakage. This is the first mechanistic overview that unveils a comprehensive insight into aflatoxin contamination in peanuts, its prevalence, health effects, and management in addition to nanotechnological interventions that serve as a triple defense approach to detoxify aflatoxins. The optimum use of nanofungicides ensures food safety and the development of goals, especially "zero hunger".

Agriculture and environmental management through nanotechnology: Eco-friendly nanomaterial synthesis for soil-plant systems, food safety, and sustainability

Through the advancement of nanotechnology, agricultural and food systems are undergoing strategic enhancements, offering innovative solutions to complex problems. This scholarly essay thoroughly examines nanotechnological innovations and their implications within these critical industries. Traditional practices are undergoing radical transformation as nanomaterials emerge as novel agents in roles traditionally filled by fertilizers, pesticides, and biosensors. Micronutrient management and preservation techniques are further enhanced, indicating a shift towards more nutrient-dense and longevity-oriented food production. Nanoparticles (NPs), with their unique physicochemical properties, such as an extraordinary surface-to-volume ratio, find applications in healthcare, diagnostics, agriculture, and other fields. However, concerns about their potential overuse and bioaccumulation raise unanswered questions about their health effects. Molecule-to-molecule interactions and physicochemical dynamics create pathways through which nanoparticles cause toxicity. The combination of nanotechnology and environmental sustainability principles leads to the examination of green nanoparticle synthesis. The discourse extends to how nanomaterials penetrate biological systems, their applications, toxicological effects, and dissemination routes. Additionally, this examination delves into the ecological consequences of nanomaterial contamination in natural ecosystems. Employing robust risk assessment methodologies, including the risk allocation framework, is recommended to address potential dangers associated with nanotechnology integration. Establishing standardized, universally accepted guidelines for evaluating nanomaterial toxicity and protocols for nano-waste disposal is urged to ensure responsible stewardship of this transformative technology. In conclusion, the article summarizes global trends, persistent challenges, and emerging regulatory strategies shaping nanotechnology in agriculture and food science. Sustained, in-depth research is crucial to fully benefit from nanotechnology prospects for sustainable agriculture and food systems.

The potential biological activities of Aspergillus luchuensis-aided green synthesis of silver nanoparticles

Biosynthetic metals have attracted global attention because of their safety, affordability, and environmental friendliness. As a consequence, the cell-free filtrate (CFF) of Dill leaf-derived endophytic fungus Aspergillus luchuensis was employed for the extracellularly synthesis silver nanoparticles (AgNPs). A reddish-brown color shift confirmed that AgNPs were successfully produced. The obtained AgNPs were characterized by UV-Vis (ultraviolet-visible spectroscopy), Transmission electron microscopy (TEM), FTIR, EDX, and zeta potential. Results demonstrated the creation of crystalline AgNPs with a spherical shape at 427.81 nm in the UV-Vis spectrum, and size ranged from 16 to 18 nm as observed by TEM. Additionally, the biogenic AgNPs had a promising antibacterial activity versus multidrug-resistant bacteria, notably, S. aureus, E. coli, and S. typhi. The highest growth reduction was recorded in the case of E. coli. Furthermore, the biosynthesized AgNPs demonstrated potent antifungal potential versus a variety of harmful fungi. The maximum growth inhibition was evaluated from A. brasinsilles, followed by C. albicans as compared to cell-free extract and AgNO3. In addition, data revealed that AgNPs possess powerful antioxidant activity, and their ability to scavenge radicals increased from 33.0 to 85.1% with an increment in their concentration from 3.9 to 1,000 μg/mL. Furthermore, data showed that AgNPs displayed high catalytic activity of safranin under light irradiation. The maximum decolorization percentage (100%) was observed after 6 h. Besides, the biosynthesized AgNPs showed high insecticidal potential against 3rd larval instar of Culex pipiens. Taken together, data suggested that endophytic fungus, A. luchuensis, is an attractive candidate as an environmentally sustainable and friendly fungal nanofactory.

Recent Advancements and Unexplored Biomedical Applications of Green Synthesized Ag and Au Nanoparticles: A Review

Green synthesis of silver (Ag) and gold (Au) nanoparticles (NPs) has acquired huge popularity owing to their potential applications in various fields. A large number of research articles exist in the literature describing the green synthesis of Ag and Au NPs for biomedical applications. However, these findings are scattered, making it time-consuming for researchers to locate promising advancements in Ag and Au NPs synthesis and their unexplored biomedical applications. Unlike other review articles, this systematic study not only highlights recent advancements in the green synthesis of Ag and Au NPs but also explores their potential unexplored biomedical applications. The article discusses the various synthesis approaches for the green synthesis of Ag and Au NPs highlighting the emerging developments and novel strategies. Then, the article reviews the important biomedical applications of green synthesized Ag and Au NPs by critically evaluating the expected advantages. To expose future research direction in the field, the article describes the unexplored biomedical applications of the NPs. Finally, the articles discuss the challenges and limitations in the green synthesis of Ag and Au NPs and their biomedical applications. This article will serve as a valuable reference for researchers, working on green synthesis of Ag and Au NPs for biomedical applications.

Endophytic Aspergillus hiratsukae mediated biosynthesis of silver nanoparticles and their antimicrobial and photocatalytic activities

In the current study, endophytic Aspergillus hiratsukae was used for the biosynthesis of silver nanoparticles (Ag-NPs) for the first time. The characterizations were performed using X ray diffraction (XRD), Transmission electron microscopy (TEM), Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), Dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR), and UV-Vis spectroscopy. The obtained results demonstrated the successful formation of crystalline, spherical Ag-NPs with particle diameters ranging from 16 to 31 nm. The FT-IR studied and displayed the various functional groups involved, which played a role in capping and reducing agents for Ag-NPs production. The SEM-EDX revealed that the main constituent of the AS-formed sample was primarily Ag, with a weight percentage of 64.2%. The mycosynthesized Ag-NPs were assessed for antimicrobial as well as photocatalytic activities. The antimicrobial results indicated that the synthesized Ag-NPs possess notable antibacterial efficacy against Staphylococcus aureus, Bacillus subtilis, and Escherichia coli, with minimum inhibitory concentrations (MICs) of Ag-NPs ranging from 62.5 to 250 μg/mL. Moreover, the biosynthesized Ag-NPs demonstrated weak antifungal activity against Aspergillus brasiliensis and Candida albicans, with MICs of 500 and 1,000 μg/mL, respectively. In addition, the mycosynthesized Ag-NPs exhibited photocatalytic activity toward acid black 2 (nigrosine) dye under both light and dark stimulation. Notably, After 300 min exposure to light, the nigrosine dye was degraded by 93%. In contrast, 51% degradation was observed after 300 min in darkness. In conclusion, Ag-NPs were successfully biosynthesized using endophytic A. hiratsukae and also exhibited antimicrobial and photocatalytic activities that can be used in environmental applications.

Biomedical and ecosafety assessment of marine fish collagen capped silver nanoparticles

In the rapidly evolving landscape of silver nanoparticles (Ag NPs) synthesis, the focus has predominantly been on plant-derived sources, leaving the realm of biological or animal origins relatively uncharted. Breaking new ground, our study introduces a pioneering approach: the creation of Ag NPs using marine fish collagen, termed ClAg NPs, and offers a comprehensive exploration of their diverse attributes. To begin, we meticulously characterized ClAg NPs, revealing their spherical morphology, strong crystalline structure, and average diameter of 5 to 100 nm. These NPs showed potent antibacterial activity, notably against S. aureus (gram-positive), surpassing their efficacy against S. typhi (gram-negative). Additionally, ClAg NPs effectively hindered the growth of MRSA biofilms at 500 μg/mL. Impressively, they demonstrated substantial antioxidant capabilities, out performing standard gallic acid. Although higher concentrations of ClAg NPs induced hemolysis (41.804 %), lower concentrations remained non hemolytic. Further evaluations delved into the safety and potential applications of ClAg NPs. In vitro cytotoxicity studies on HEK 293 and HeLa cells revealed dose-dependent toxicity, with IC50 of 75.28 μg/mL and 79.13 μg/mL, respectively. Furthermore, ClAg NPs affected seed germination, root, and shoot lengths in Mung plants, underscoring their relevance in agriculture. Lastly, zebrafish embryo toxicity assays revealed notable effects, particularly at 500 μg/mL, on embryo morphology and survival rates at 96 hpf. In conclusion, our study pioneers the synthesis and multifaceted evaluation of ClAg NPs, offering promise for their use as versatile nano therapeutics in the medical field and as high-value collagen-based nanobiomaterial with minimal environmental impact.

Frontiers of stem cell engineering for nanotechnology-mediated drug delivery systems

Background and purpose

Cell biology approaches have gained a successful integration, development and application of nanotechnology with stem cell engineering and have led to the emergence of a new interdisciplinary field known as stem cell nanotechnology (SCN). Recent studies showed the potential and the advancement of developments for SCN applications in drug delivery systems. Cancer, neurodegenerative, muscle and blood diseases, cell and gene therapies, and tissue engineering and regenerative medicine applications are the important targets of SCN.

Experimental approach

In this overview, we searched the literature using the common online websites for research and read the open access, full-text available articles since 2013.

Key results

The studies vary according to the type of disease they targeted and the strategies they proposed, whether diagnostic or therapeutic. In addition to the use of stem cells, the utilisation of their membranes, secretomes, exosomes and extracellular vesicles with an appropriate nanotechnology strategy is also an aspect of the research.

Conclusion

This brief overview of stem cell nanotechnology over the last ten years aims to provide insight into the frontiers of stem cell engineering for nanotechnology-mediated drug delivery systems.

Nanotechnology for controlling mango malformation: a promising approach

Mango (Mangifera indica L.) is one of the most important fruit crops in the world with yields of approximately 40 million tons annually and its production continues to decrease every year as a result of the attack of certain pathogens i.e. Colletotrichum gloeosporioides, Erythricium salmonicolor, Amritodus atkinsoni, Idioscopus clypealis, Idioscopus nitidulus, Bactrocera obliqua, Bactrocera frauenfeldi, Xanthomonas campestris, and Fusarium mangiferae. So F. mangiferae is the most harmful pathogen that causes mango malformation disease in mango which decreases its 90% yield. Nanotechnology is an eco-friendly and has a promising effect over traditional methods to cure fungal diseases. Different nanoparticles possess antifungal potential in terms of controlling the fungal diseases in plants but applications of nanotechnology in plant disease managements is minimal. The main focus of this review is to highlight the previous and current strategies to control mango malformation and highlights the promising applications of nanomaterials in combating mango malformation. Hence, the present review aims to provide brief information on the disease and effective management strategies.Communicated by Ramaswamy H. Sarma.

Beyond traditional biosensors: Recent advances in gold nanoparticles modified electrodes for biosensing applications

Gold nanoparticles (AuNPs) have emerged as powerful tools in the construction of highly sensitive electrochemical biosensors. Their unique properties, such as the ability to serve as an effective platform for biomolecule immobilization and to facilitate electron transfer between the electrode surface and the immobilized molecules, make them a promising choice for biosensor applications. Utilizing AuNPs modified electrodes can lead to improved sensitivity and lower limits of detection compared to unmodified electrodes. This review provides a comprehensive overview of the recent advancements and applications of AuNPs-based electrochemical biosensors in the biomedical field. The synthesis methods of AuNPs, their key properties, and various strategies employed for electrode modification are discussed. Furthermore, this review highlights the remarkable applications of these nanostructure-integrated electrodes, including immunosensors, enzyme biosensors, and DNA biosensors.

Thespesia lampas mediated green synthesis of silver and gold nanoparticles for enhanced biological applications

The present study investigated the synthesis and biological applications of green, economical, and multifunctional silver and gold nanoparticles (TSAgNPs and TSAuNPs) using the ethnomedical important medicinal plant Thespesia lampas for biological activities. Relatively higher levels of antioxidant components were measured in T. lampas compared to the well-known Adhatoda vasica, and Diplocyclos palmatus suggested the potential of T. lampas for the study. Synthesized TSAgNPs and TSAuNPs were characterized through UV-Vis, XRD, SEM-EDS, HR-TEM, SAED, and FTIR techniques. SEM revealed that TSAgNPs and TSAuNPs were predominantly spherical in shape with 19 ± 7.3 and 43 ± 6.3 nm crystal sizes. The sizes of TSAgNPs and TSAuNPs were found to be12 ± 4.8 and 45 ± 2.9 nm, respectively, according to TEM measurements. The FTIR and phytochemical analyses revealed that the polyphenols and proteins present in T. lampas may act as bio-reducing and stabilizing agents for the synthesis. Synthesized NPs exhibited enhanced scavenging properties for ABTS and DPPH radicals. TSAgNPs and TSAuNPs were able to protect DNA nicking up to 13.48% and 15.38%, respectively, from oxidative stress. TSAgNPs possessed efficient antibacterial activities in a concentration-dependent manner against human pathogenic bacteria, such as E. coli, B. subtilis, P. vulgaris, and S. typhi. Furthermore, TSAgNPs and TSAuNPs showed significant cytotoxicity against FaDu HNSCC grown in 2D at 50 and 100 μg mL-1. Tumor inhibitory effects on FaDu-derived spheroid were significant for TSAgNPs > TSAuNPs at 100 μg mL-1 in 3D conditions. Dead cells were highest largely for TSAgNPs (76.65% ± 1.76%), while TSAuNPs were non-significant, and Saq was ineffectively compared with the control. However, the diameter of the spheroid drastically reduced for TSAgNPs (3.94 folds) followed by TSAuNPs (2.58 folds), Saq (1.94 folds), and cisplatin (1.83 folds) at 100 μg mL-1. The findings of the study suggested the bio-competence of TSAgNPs and TSAuNPs as multi-responsive agents for antioxidants, DNA protection, antibacterial, and anti-tumor activities to provide a better comprehension of the role of phytogenic nanoparticles in healthcare systems.

Review green synthesis of silver nanoparticles by using plant extracts and their antimicrobial activity

Interest in the biosynthesis of nanoparticles has increased in the last era by researchers. Nanoparticles have several applications in different fields like optoelectronics, magnetic devices, drug delivery, and sensors. Nanoparticle synthesis by green methods is safe for the environment and should be explored and encouraged popularly since various plants' have the high extent to form these nanoparticles. Worldwide, UV spectroscopy, X-ray diffraction, Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS), Atomic Force Microscopy (AFM) besides Fourier Transform Infrared Spectroscopy (FTIR) are used in many ways for characterize nanoparticles. The most advantageous use of AgNPs is their great attribution to be used as antimicrobial agents. Finally, concept of AgNPs synthesis is deserved to be the modern technical and medical concern. The current review shows a complete comprehensive and analytical survey of the biosynthesis of AgNPs with a particular focus on their activities as antimicrobials and the possible theories of their effect on the microbial cell and all influenced secondary metabolites.

From nature to nanotechnology: The interplay of traditional medicine, green chemistry, and biogenic metallic phytonanoparticles in modern healthcare innovation and sustainability

As we navigate the modern era, the intersection of time-honoured natural remedies and contemporary scientific approaches forms a burgeoning frontier in global healthcare. For generations, natural products have been foundational to health solutions, serving as the primary healthcare choice for 80% to 85% of the world's population. These herbal-based, nature-derived substances, significant across diverse geographies, necessitate a renewed emphasis on enhancing their quality, efficacy, and safety. In the current century, the advent of biogenic phytonanoparticles has emerged as an innovative therapeutic conduit, perfectly aligning with principles of environmental safety and scientific ingenuity. Utilizing green chemistry techniques, a spectrum of metallic nanoparticles including elements such as copper, silver, iron, zinc, and titanium oxide can be produced with attributes of non-toxicity, sustainability, and economic efficiency. Sophisticated herb-mediated processes yield an array of plant-originated nanomaterials, each demonstrating unique physical, chemical, and biological characteristics. These attributes herald new therapeutic potentials, encompassing antioxidants, anti-aging applications, and more. Modern technology further accelerates the synthesis of natural products within laboratory settings, providing an efficient alternative to conventional isolation methods. The collaboration between traditional wisdom and advanced methodologies now signals a new epoch in healthcare. Here, the augmentation of traditional medicine is realized through rigorous scientific examination. By intertwining ethical considerations, cutting-edge technology, and natural philosophy, the realms of biogenic phytonanoparticles and traditional medicine forge promising pathways for research, development, and healing. The narrative of this seamless integration marks an exciting evolution in healthcare, where the fusion of sustainability and innovation crafts a future filled with endless possibilities for human well-being. The research in the development of metallic nanoparticles is crucial for unlocking their potential in revolutionizing fields such as medicine, catalysis, and electronics, promising groundbreaking applications with enhanced efficiency and tailored functionalities in future technologies. This exploration is essential for harnessing the unique properties of metallic nanoparticles to address pressing challenges and advance innovations across diverse scientific and industrial domains.

A practical green synthesis method of Ag NPs using rosy periwinkle plant leaves for solar panel coating

Coated silver nanoparticles (Ag NPs) are currently receiving interest because of their numerous uses in various fields of electronics, antimicrobials, manufacturing sectors, optical science, and pharmaceuticals. Among others, it gained significant attention in the power electronic system. The goal of the proposed study is to use a cost-effective coating material for solar panels; to accomplish this, silver nanoparticles were synthesized from the leaves of the Rosy Periwinkle plants. Green synthesis and characterization, such as Ultraviolet Visible Spectrometer (UV-Vis) analysis, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), and Fourier Transform Infrared Spectroscopy (FTIR), were carried out after the silver nanoparticles have been collected prior coating. As a consequence, the effectiveness is determined based on the conductivity test, and the resulting Ag NPs are then applied to the c-si layer of the solar panel. Additionally, a modelling and experimental analysis are performed in this study to ascertain the suggested framework's ability to measure energy before and after coating panels with Ag NPs. Specifically, the Voltage Current (VI) and Power Voltage (PV) characteristics were validated in this study for analyzing the effectiveness and the obtained results revealed that the coating of green synthesized Ag NPs generated 2 % more power than the reference solar panel under the same conditions. Further, hardware testing and simulation were both used to confirm the outcomes and effectiveness of the suggested method. The open circuit voltage (Voc), short circuit current (Isc), maximum peak voltage (Vmp), maximum peak current (Imp), and efficiency are taken into account when assessing how well the suggested system performs at tracking. Moreover, the current density characteristics were evaluated with respect to various irradiation conditions for both the typical solar as well as Ag NPs coated panels. From the observation, it is noted that the efficiency level of coated panel was improved up to 19.20 %, 18 %, and 17.20 % for the irradiations of 200 W/m2, 500 W/m2, and 1000 W/m2 respectively.

Loading of green-synthesized cu nanoparticles on Ag complex containing 1,3,5-triazine Schiff base with enhanced antimicrobial activities

The physicochemical properties of materials change significantly in nanometer dimensions. Therefore, several methods have been proposed for the synthesis of nanoparticles. Plant extracts and essential oils are applied as natural and economic resources to prepare nanomaterials especially metal nanoparticles. In this project, a green, simple and efficient method has been designed for the synthesis of Cu nanoparticles using Purple cabbage extract as a reducing and stabilizing agent. They were successfully loaded onto a new Ag complex containing 1,3,5-triazine Schiff base as ligand to form Cu@Ag-CPX nanocomposite. Phytochemical contents of extract were identified by standard qualitative analyses. The chemical structure of all synthesized compounds was characterized using spectral data. In FT-IR, coordination of C=N bond of Schiff base ligand to Ag+ ions shifted the absorption band from 1641 to 1632 cm-1. The UV-Vis spectrum of Cu@Ag-CPX nanocomposite shown the peak related to Cu nanoparticles in the region of around 251 nm. 5:7 molar ratio of Cu to Ag in Cu@Ag-CPX was determined using ICP-OES. The FESEM, TEM, and DLS techniques provided valuable insights into the morphology and size distribution of the nanocomposite, revealing the presence of rods and monodispersed particles with specific diameter ranges. These analyses of the nanocomposite displayed rods with diameters from 40 to 62 nm as well as monodispersed and uniform particles with average diameter of 45 nm, respectively. The presence of elements including carbon, nitrogen, oxygen, Cu and Ag was proved by EDX-EDS analysis. The XRD pattern of Cu@Ag-CPX shown the diffraction peaks of Cu and Ag particles at 2θ values of 10°-80°, and confirmed its crystalline nature. The inhibitory properties of the synthesized compounds were evaluated in vitro against four Gram-negative and two Gram-positive bacteria, as well as two fungal strains. The MIC, MBC and MFC values obtained from microdilution and streak plate sensitivity tests were ranged from 128 to 4096 µg ml-1. While Cu nanoparticles and Ag complexes were effective against some pathogens, they were not effective against all them. However, the growth of all tested microbial strains was inhibited by Cu@Ag-CPX nanocomposite, and makes it as a new promising antimicrobial agent. Modification of nanocomposite in terms of nanoparticle and complex can improve its blocking activities.

Green biosynthesis of silver and gold nanoparticles using Teak (Tectona grandis) leaf extract and its anticancer and antimicrobial activity

The green synthesis of nanoparticles (NPs) utilizing a green path is eco-friendly and profitable compared to traditional physical and chemical techniques. This research conducted a green synthesis of gold NPs (AuNPs) and silver NPs (AgNPs) using an extract of Teak (Tectona grandis) and their anticancer and anti-microbial activities. Various techniques like transmission-electron microscopy (TEM), UV-Vis spectroscopy, thermal-gravimetric analyses (TGA), X-ray diffraction (XRD), and Fourier transform-infrared spectroscopy (FT-IR) were used to analyze synthesized AuNPs and AgNPs. The effects of different factors like the amount of extract used, solution pH, and contact time were measured to obtain the best possible conditions for synthesizing NPs. The AgNPs showed significant anticancer activity against HepG2 with an IC50 of 6.17 mg/ml compared to Teak extract (>50 mg/ml) and AuNPs (44.1 mg/ml), while AuNPs (6 % Teak extract and 2.9 × 10-3 M HAuCl4) showed significant antibacterial and antifungal activity against Pseudomonas aeruginosa, Aspergillus niger, Bacillus subtilis, and Escherichia coli with an inhibition zone of 11 mm, 12 mm, 12.5 mm, and 15.5 mm, respectively as compared to other treatments. These findings confirmed the medical applications of AuNPs and AgNPs and might open new possibilities in this field.

Biogenic polymer nanoparticles to remove hydrophobic organic contaminants from water

Soil and water pollution is of significant concern worldwide because of the consequences of environmental degradation and harmful effects on human health. Water bodies are very much polluted by various organic and inorganic pollutants by different human activities, including industrial wastes. Environmental pollution remains high because of urbanization-induced industrial developments and human lifestyle. It accumulates pollutants in the environment including plants and living organisms. Even mothers' milk is poisoned because of the uncontrolled, widespread increase in pollution. The discharge levels of organic hydrophobic contaminants in the water and soil are increasing rapidly. This severe pollution must be remediated to upgrade the environment and ensure the safety of human beings. It is vital to eradicate soil and water pollution to guarantee sufficient food and water. Different techniques available to remove the pollutants vary according to the type of pollutants. Hydrophobic contaminants are more dangerous than heavy metals and other pollutants; they cannot be easily removed, requiring special care. Hydrophobic organoxenobiotics released in the environment pose severe contamination in soil and water. Therefore, developing efficient and cost-effective processes is necessary to remove hydrophobic contaminants from soil and water. With nanoparticle-mediated remediation techniques, the green-synthesized nanoparticles exhibit improved performance. This review consolidates reports on the remediation techniques of hydrophobic contaminants, focusing on green-synthesized remediation agents. The very limited works on green synthesis of polymeric nanoparticles, particularly polyurethane-based materials for organic contaminants removal demand more attention in this area. PRACTITIONER POINTS: Consolidated the effects of hydrophobic organic and plastic contaminants on environment degradation. Summarized the advantages of green synthesized polymer nanoparticles for efficient removal of hydrophobic contaminants. Discussed the different sources of pollution and remediation techniques referring 112 research works.

Evaluation of antibacterial activity, in-vitro cytotoxicity and catalytic activity of biologically synthesized silver nanoparticles using leaf extracts of Leea macrophylla

Nanotechnology has become a cutting-edge field of research that has emerged as an interdisciplinary research area and contributes to almost every field of science. With the increasing demand for sustainable greener products, attention has recently been focused on green nanotechnology. This study manifested the aptitude of Leea macrophylla (LM) leaf extract, fortified with phytochemicals, to biosynthesize silver nanoparticles (AgNPs) for the first time. As soon as the AgNPs were biosynthesized, they immediately changed color, and the distinctive surface plasmon resonance (SPR) occurred at 420 nm in the Ultraviolet-Visible spectrum, proving that the biosynthesis had been successful. Fourier Transform Infrared Spectroscopy (FTIR) was used to examine the phytochemicals present in the LM leaf extract, those are accountable for the formation and stabilization of AgNPs. The Transmission Electron Microscope (TEM) revealed the formation of quasi spherical silver nanoparticles with an average diameter of 22.77 nm. Synthesized nanoparticles were further characterized by X-ray diffraction (XRD), Field Emission Scanning Electron microscope (FESEM), Energy Dispersive X-ray (EDX), Dynamic Light Scattering (DLS) and Thermogravimetric analysis (TGA). The production of AgNPs with high metal content from LM leaf extract exhibited encouraging results. The LM leaf extract mediated silver nanoparticles evinced significant antibacterial and catalytic activities. The cytotoxicity effects of biosynthesized AgNPs were tested on brine shrimps.

Biosynthesis, Spectroscopic, and Antibacterial Investigations of Silver Nanoparticles

Silver nanoparticles can be produced by an array of procedures, such as chemical, physical, and biological processes. The process of biosynthesis is more economical and significantly more environmentally friendly. We describe an environmentally compatible method (biosynthesis) of producing silver nanoparticles (Ag: NPs) with the capping component Artocarpus heterophyllus in this research work. Powder-X-ray crystallography (P-XRD), Fourier Transform Infrared (FT-IR), UV-visible (UV-Vis), Photoluminescence (PL), Field emission scanning electron microscopy (FE-SEM), and an antimicrobial test were all used to examine the synthesized samples. The P-XRD analysis revealed that the produced NPs have an FCC form with a typical particle size of 23 nm. FT-IR spectra further demonstrate the availability of the functional groups in the synthesized nanoparticles. The absorbance and transmittance spectra of the UV-Vis study have shown substantial transparency and less absorbance of the Ag: NPs in the entire visible region. The bandgap of the Ag: NPs was found to be 3.25 eV using the Tauc relation. In the PL study, an emission peak at 472 nm was found, suggesting the fluorescence emission of Ag: NPs. The FE-SEM micrographs provide confirmation of the surface-wide aggregate of nanostructural homogeneities. The FE-SEM micrographs illustrate that Ag: NPs are homogeneous aggregates of very small spheres. Variations in particle size and surface area-to-volume ratios of synthesized NPs have been proven to be responsible for the antibacterial activities. According to the antibacterial study, Ag: NPs restrain the development of both normal and harmful bacteria and so have the potential to be utilized for coating surgical equipment for aseptic operators in the healthcare industry.

In-vivo anticoccidial efficacy of green synthesized iron-oxide nanoparticles using Ficus racemosa Linn leaf extract. (Moraceae) against Emeria tenella infection in broiler chicks

Coccidiosis is an acute gastrointestinal parasitic disease and causes approximately $2.80 to $3.27 per m2 loss in a broiler farm of a 33-day-old flock. In this study, iron oxide nanoparticles (IONPs) were green synthesized using the aqueous leaf extract of Ficus racemosa as a reducing and capping agent to reduce the emerging resistance in coccidia spores against conventional treatments and boost the immune level in broilers. These IONPs were evaluated for their impacts on the growth performance, biochemistry, blood profile, and histology in the coccidiodized broiler chicken with Emeria tenella under in vivo conditions. The characteristics and stability of particles were obtained using UV-Vis spectroscopy, Fourier transforms infrared (FTIR), X-Ray diffraction (XRD), energy dispersive X-ray absorption (EDX), scanning electron microscopy (SEM), zeta potential and zeta size. The results indicated that IONPs at the moderate dose of 15 mg/kg (p = 0.001) reduced the coccidial impacts by eliminating oocyst shedding per gram feces (up to 91%) and reducing clinical symptoms (lesions (LS = 0), bloody diarrhea (No), and mortality (0%) in chicken at day 10 of treatment as compared to the negative control group-B (infected & non-treated). A dose-dependent and time-dependent trend were observed during treatments (10, 15, and 20 mg/kg) of 1-3 weeks using IONPs against the coccidial impacts on the growth parameters (body weight gain, mean feed consumption, feed conversion ratio) and biochemistry (plasma glucose, total protein, uric acid, ALT, AST, and ALP) in chickens. Additionally, F. racemosa IONPs at a dose of 15 and 20 mg/kg significantly recovered the parasitized and highly damaged hepatocytes, liver tissues, and ceca tissues after 1-3 weeks of treatment in broiler chickens. Overall, the 15 mg/kg concentration of IONPs exhibited fast recovery and growth enhancement in coccidiodized broilers. Therefore, the 15 mg/kg dose of green synthesized IONPs using leaf extract of F. racemosa could be a potential and safe anticoccidial agent with targeted implications in the poultry industry.

Biosynthesis, characterization, and investigation of antimicrobial and cytotoxic activities of silver nanoparticles using Solanum tuberosum peel aqueous extract

Metallic nanoparticle biosynthesis is thought to offer opportunities for a wide range of biological uses. The green process of turning biological waste into utilizable products gaining attention due to its economical and eco-friendly approach in recent years. This study reported the ability of Solanum tuberosum (ST) peel extract to the green synthesis of non-toxic, stable, small-sized silver nanoparticles without any toxic reducing agent utilizing the phytochemical components present in its structure. UV-visible spectroscopy, X-ray diffraction analysis, Fourier transform infrared spectroscopy, flourier scanning electron microscopy, atomic force microscopy, transmission electron microscopy, and energy dispersive analysis X-ray confirmed the biosynthesis and characterization of silver nanoparticles. Also, dynamic light scattering and thermogravimetric analyses showed stable synthesized nanoparticles. The antibacterial activity of the biosynthesized silver nanoparticles was evaluated against four different bacterial strains, Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Staphylococcus aureus (S. aureus) Bacillus subtilis (B. subtilis), and a yeast, Candida albicans (C. albicans) using the minimum inhibitory concentration technique. The cytotoxic activities were determined against Human dermal fibroblast (HDF), glioblastoma (U118), colorectal adenocarcinoma (CaCo-2), and human ovarian (Skov-3) cell lines cancer cells using MTT test. The nanoparticle capping agents that could be involved in the reduction of silver ions to Ag NPs and their stabilization was identified using FTIR. Nanoparticles were spherical in shape and had a size ranging from 3.91 to 27.07 nm, showed crystalline nature, good stability (-31.3 mV), and the presence of capping agents. ST-Ag NPs significantly decreased the growth of bacterial strains after treatment. The in vitro analysis showed that the ST-Ag NPs demonstrated dose-dependent cytotoxicity against cell lines. Based on the data, it is feasible to infer that biogenic Ag NPs were capped with functional groups and demonstrated considerable potential as antibacterial and anticancer agents for biomedical and industrial applications.

A new strategy to achieve high antimicrobial activity: green synthesised silver nanoparticle formulations with Galium aparine and Helichrysum arenarium

Silver nanoparticles (AgNPs), which have recently gained attention due to their antimicrobial activity, can also be produced by green synthesis. The aims of this study were to (i) characterise green synthesized AgNPs using microwave-assisted aqueous extracts of Galium aparine (G-AgNPs) and Helichrysum arenarium (H-AgNPs) and (ii) investigate the combined antimicrobial effects of the G- and H-AgNPs in different ratios. Nanoparticle formation and reactions were determined with UV-Vis spectroscopy. The G-AgNPs were 52.0±10.9 nm in size, with a 0.285±0.034 polydispersity index (PDI), and a -17.9±0.9 mV zeta potential. For H-AgNPs these characteristics were 23.9±1.0 nm, 0.280±0.032, and -21.3±2.7 mV, respectively. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) confirmed that the particles were monodisperse and spherical. The Fourier transform-infrared spectroscopy (FT-IR) results showed the presence of reducing agents that stabilised the AgNPs. Three different nanoformulations (NF-1, NF-2, and NF-3) were prepared by combining these two synthesised nanoparticles in different ratios and their antimicrobial activity was tested against E. coli, S. aureus, C. albicans, and A. flavus. Our study is the first to show that combining AgNPs from two different biological sources can produce effective nanoformulations with improved antibacterial activity against E. coli and S. aureus. These nanoformulations showed lower minimum inhibitory concentrations (31.25 µg/mL against E. coli with all NFs; 62.5 µg/mL for NF-1 and 125 µg/mL for NF-2/3 against S. aureus) than G-AgNPs (62.5 µg/mL for E. coli) or H-AgNPs (125 µg/mL for S. aureus) alone. Their high combined inhibitory effect against E. coli (NF-1-3) was synergistic and against S. aureus (NF-2 and NF-3) potentially additive. Considering such promising results, we believe our study provides some direction for new research and strategies in antimicrobial therapeutics.

Silver nanoparticles green synthesized with leaf extract of disease-resistant amaranthus genotypes effectively suppress leaf blight (Rhizoctonia solani Kühn) disease in a susceptible red amaranthus cultivar

Silver nanoparticles (AgNPs) were green synthesized using leaf extract of the leaf blight disease (Rhizoctonia solani) susceptible red amaranthus (Amaranthus tricolor L.) and the disease-resistant green (A. dubius) and the wild amaranthus (A. viridis) genotypes, physically characterized, and assessed for their anti-fungal effects against R. solani. The green synthesized nanostructures showed an absorption maximum typical of silver nanoparticles in spectroscopy, and face-centered cubic structures in X-ray diffraction. Field Emission Scanning Electron Microscopic analysis and High-Resolution Transmission Electron Microscopy revealed the size range to be 35-45 nm for all the samples. In vitro mycelial growth inhibition of the pathogen occurred with 500 and 750 ppm concentrations of the nanoparticles in a poisoned-food assay. Further, detached leaves of red amaranthus variety were sprayed with the nanoparticles, and then challenged with the pathogen. There was significant difference in lesion development on leaves sprayed with Ad-AgNPs and Av-AgNPs compared to those treated with At-AgNPs. In the in vivo assay, challenging with the pathogen after spraying the foliage of the leaf blight susceptible red amaranthus variety with Ad-AgNPs at 750 ppm concentration recorded the lowest disease index (7.40) followed by that received Av-AgNPs spray at the same concentration (17.69), five days after inoculation. At-AgNPs treated plants had a disease index of 49.38. Our findings suggest that application of AgNPs green synthesized with leaf extract of disease-resistant genotypes of amaranthus effectively suppressed leaf blight disease incidence in a susceptible amaranthus genotype. To our knowledge, this is the first report on the improved plant pathogen-suppressive activity of any metal nanoparticle when biogenically synthesized using extracts from a disease-resistant plant genotype.

Nanotechnology: A promising strategy for the control of parasitic infections

Annually 3.5 billion people are affected by the parasitic infections that results around 200,000 deaths per annum. Major diseases occur due to the neglected tropical parasites. Variety of methods have been used to treat the parasitic infections but now these methods have become ineffective due to the development of resistance in the parasites and some other side effects of traditional treatment methods. Previous methods include use of chemotherapeutic agents and ethnobotanicals for the treatment of parasites. Parasites have developed resistance against the chemotherapeutic agents. A major problem related to Ethnobotanicals is the unequal availability of drug at the target site which is responsible for the low efficacy of drug. Nanotechnology technology involves the manipulation of matter on a nanoscale level and has the potential to enhance the efficacy and safety of existing drugs, develop new treatments, and improve diagnostic methods for parasitic infections. Nanoparticles can be designed to selectively target parasites while minimizing toxicity to the host, and they can also be used to improve drug delivery and increase drug stability. Some important nanotechnology-based tools for parasitic control include nanoparticle-based drug delivery, nanoparticle diagnostics, nanoparticle vaccines, nanoparticle insecticides. Nanotechnology has the potential to revolutionize the field of parasitic control by providing new methods for detection, prevention and treatment of parasitic infections. This review discusses the current state of nanotechnology-based approaches for controlling parasitic infections and highlights their potential to revolutionize the field of parasitology.

A review on the green synthesis of nanoparticles, their biological applications, and photocatalytic efficiency against environmental toxins

Green synthesis of nanoparticles (NPs) using plant materials and microorganisms has evolved as a sustainable alternative to conventional techniques that rely on toxic chemicals. Recently, green-synthesized eco-friendly NPs have attracted interest for their potential use in various biological applications. Several studies have demonstrated that green-synthesized NPs are beneficial in multiple medicinal applications, including cancer treatment, targeted drug delivery, and wound healing. Additionally, due to their photodegradation activity, green-synthesized NPs are a promising tool in environmental remediation. Photodegradation is a process that uses light and a photocatalyst to turn a pollutant into a harmless product. Green NPs have been found efficient in degrading pollutants such as dyes, herbicides, and heavy metals. The use of microbes and flora in green synthesis technology for nanoparticle synthesis is biologically safe, cost-effective, and eco-friendly. Plants and microbes can now use and accumulate inorganic metallic ions in the environment. Various NPs have been synthesized via the bio-reduction of biological entities or their extracts. There are several biological and environmental uses for biologically synthesized metallic NPs, such as photocatalysis, adsorption, and water purification. Since the last decade, the green synthesis of NPs has gained significant interest in the scientific community. Therefore, there is a need for a review that serves as a one-stop resource that points to relevant and recent studies on the green synthesis of NPs and their biological and photocatalytic efficiency. This review focuses on the green fabrication of NPs utilizing diverse biological systems and their applications in biological and photodegradation processes.

Biogenic silver based nanostructures: Synthesis, mechanistic approach and biological applications

The alarming impact of antibiotic resistance sparked the quest for complementary treatments to overcome the confrontation over resistant pathogens. Metallic nanoparticles, especially silver nanoparticles (Ag NPs) have gained a much attention because of their remarkable biological characteristics. Moreover, their medicinal properties can be enhanced by preparing the composites with other materials. This article delves a comprehensive review of biosynthesis route for Ag NPs and their nanocomposites (NCs) with in-depth mechanism, methods and favorable experimental parameters. Comprehensive biological features Ag NPs such as antibacterial, antiviral, antifungal have been examined, with a focus on their potential uses in biomedicine and diagnostics has also been discussed. Additionally, we have also explored the hitches and potential outcomes of biosynthesis of Ag NPs in biomedical filed.

Nanobiotechnological approaches in antinociceptive therapy: Animal-based evidence for analgesic nanotherapeutics of bioengineered silver and gold nanomaterials

Pain management is a major challenge in healthcare systems worldwide. Owing to undesirable side effects of current analgesic medications, there is an exceeding need to develop the effective alternative therapeutics. Nowadays, the application of nanomaterials is being highly considered, as their exceptional properties arising from the nanoscale dimensions are undeniable. With the increasing use of metal NPs, more biocompatible and costly methods of synthesis have been developed in which different biological rescores including microorganisms, plants and algae are employed. Nanobiotechnology-based synthesis of nanosized particles is an ecological approach offering safe production of nanoparticles (NPs) by biological resources eliminating the toxicity attributed to the conventional routes. This review provides an assessment of biosynthesized silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) as antinociceptive agents in recent studies. Living animal models (mice and rats) have been used for analyzing the effect of biogenic NPs on decreasing the nociceptive pain utilizing different methods such as acetic acid-induced writhing test, hot plate test, and formalin test. Potent analgesic activity exhibited by green fabricated AgNPs and AuNPs represents the bright future of nanotechnology in the management of pain and other social and medicinal issues followed by this unpleasant sensation. Moreover, there NPs showed a protective effects on liver, kidney, and body weight in animal models that make them attractive for clinical studies. However, further research is required to fully address the harmless antinociceptive effect of NPs for clinical usage.

Versatile Silver-Nanoparticle-Impregnated Membranes for Water Treatment: A Review

Increased affordability, smaller footprint, and high permeability quality that meets stringent water quality standards have accelerated the uptake of membranes in water treatment. Moreover, low pressure, gravity-based microfiltration (MF) and ultrafiltration (UF) membranes eliminate the use of electricity and pumps. However, MF and UF processes remove contaminants by size exclusion, based on membrane pore size. This limits their application in the removal of smaller matter or even harmful microorganisms. There is a need to enhance the membrane properties to meet needs such as adequate disinfection, flux amelioration, and reduced membrane fouling. To achieve these, the incorporation of nanoparticles with unique properties in membranes has potential. Herein, we review recent developments in the impregnation of polymeric and ceramic microfiltration and ultrafiltration membranes with silver nanoparticles that are applied in water treatment. We critically evaluated the potential of these membranes in enhanced antifouling, increased permeability quality and flux compared to uncoated membranes. Despite the intensive research in this area, most studies have been performed at laboratory scale for short periods of time. There is a need for studies that assess the long-term stability of the nanoparticles and the impact on disinfection and antifouling performance. These challenges are addressed in this study and future directions.

Anti-cancer activity of green synthesized silver nanoparticles using Ardisia gigantifolia leaf extract against gastric cancer cells

Using extracts from herbs for silver nanoparticle synthesis is attracting attention for its anticancer activity. Ardisia gigantifolia is a herb used in traditional Chinese medicine for treating stomach ailments, and some compounds isolated from this plant exhibit the inhibitory activity against different cancer cells. However, the synthesis of silver nanoparticle using extract of Ardisia gigantiflia leaves and their anti-cancer activity was not reported. In this report, the green synthesized silver nanoparticles using Ardisia gigantiflia extract (Arg-AgNPs) has average diameter of 6 nm with functional groups including O-H, C-H, and CO founded on the surface of these nanoparticles. The viability assays results revealed Arg-AgNPs reduced gastric cancer cell proliferation in a dose-dependent manner, with IC₅₀ values of 1.37 and 0.65 μg/mL for AGS cells and 1.03 and 0.96 μg/mL for MKN45 cells. Arg-AgNPs caused cell cycle arrest at the G0/G1 phase and suppressed cell migration. Additionally, Arg-AgNPs significantly increased the percentage of senescent cells and promoted overproduction of reactive oxygen species (ROS) compared to the control. Thus, this study indicates that Arg-AgNPs can be considered as a promising candidate against human gastric cancer cells.

Durian Shell-Mediated Simple Green Synthesis of Nanocopper against Plant Pathogenic Fungi

The synthesis of fungicides in eco-friendly and cost-effective ways is significantly essential for agriculture. Plant pathogenic fungi cause many ecological and economic issues worldwide, which must be treated with effective fungicides. Here, this study proposes the biosynthesis of fungicides, which combines copper and Cu₂O nanoparticles (Cu/Cu₂O) synthesized using durian shell (DS) extract as a reducing agent in aqueous media. Sugar and polyphenol compounds contained in DS, as the main phytochemicals acting in the reduction procedure, were extracted under different temperatures and duration conditions to obtain the highest yields. We confirmed the extraction process performed at 70 °C for 60 min to be the most effective in extracting sugar (6.1 g/L) and polyphenols (22.7 mg/L). We determined the suitable conditions for Cu/Cu₂O synthesis using a DS extract as a reducing agent for a synthesis time of 90 min, a volume ratio of DR extract/Cu²⁺ of 15:35, an initial pH solution of 10, a synthesis temperature of 70 °C, and a CuSO₄ concentration of 10 mM. The characterization results of as-prepared Cu/Cu₂O NP showed a highly crystalline structure of Cu₂O and Cu with sizes estimated in the range of 40-25 nm and 25-30 nm, respectively. Through in vitro experiments, the antifungal efficacy of Cu/Cu₂O against Corynespora cassiicola and Neoscytalidium dimidiatum was investigated by the inhibition zone. The green-synthesized Cu/Cu₂O nanocomposites, which are potential antifungals against plant pathogens, exhibited excellent antifungal efficacy against both Corynespora cassiicola (MIC = 0.25 g/L, the diameter of the inhibition zone was 22.00 ± 0.52 mm) and Neoscytalidium dimidiatum (MIC = 0.0625 g/L, the diameter of the inhibition zone was 18.00 ± 0.58 mm). Cu/Cu₂O nanocomosites prepared in this study could be a valuable suggestion for the control of plant pathogenic fungi affecting crop species globally.

Nanobionics: A Sustainable Agricultural Approach towards Understanding Plant Response to Heavy Metals, Drought, and Salt Stress

In the current scenario, the rising concentration of heavy metals (HMs) due to anthropogenic activities is a severe problem. Plants are very much affected by HM pollution as well as other abiotic stress such as salinity and drought. It is very important to fulfil the nutritional demands of an ever-growing population in these adverse environmental conditions and/or stresses. Remediation of HM in contaminated soil is executed through physical and chemical processes which are costly, time-consuming, and non-sustainable. The application of nanobionics in crop resilience with enhanced stress tolerance may be the safe and sustainable strategy to increase crop yield. Thus, this review emphasizes the impact of nanobionics on the physiological traits and growth indices of plants. Major concerns and stress tolerance associated with the use of nanobionics are also deliberated concisely. The nanobionic approach to plant physiological traits and stress tolerance would lead to an epoch of plant research at the frontier of nanotechnology and plant biology.

Green Synthesis of Iridium Nanoparticles from Winery Waste and Their Catalytic Effectiveness in Water Decontamination

An environmentally friendly procedure was adopted for the first time to prepare green iridium nanoparticles starting from grape marc extracts. Grape marcs, waste of Negramaro winery production, were subjected to aqueous thermal extraction at different temperatures (45, 65, 80, and 100 °C) and characterized in terms of total phenolic contents, reducing sugars, and antioxidant activity. The results obtained showed an important effect of temperature with higher amounts of polyphenols and reducing sugars and antioxidant activity in the extracts with the increase of temperature. All four extracts were used as starting materials to synthesize different iridium nanoparticles (Ir-NP1, Ir-NP2, Ir-NP3, and Ir-NP4) that were characterized by Uv-Vis spectroscopy, transmission electron microscopy, and dynamic light scattering. TEM analysis revealed the presence of very small particles in all samples with sizes in the range of 3.0-4.5 nm with the presence of a second fraction of larger nanoparticles (7.5-17.0 nm) for Ir-NPs prepared with extracts obtained at higher temperatures (Ir-NP3 and Ir-NP4). Since the wastewater remediation of toxic organic contaminants on catalytic reduction has gained much attention, the application of the prepared Ir-NPs as catalysts towards the reduction of methylene blue (MB), chosen as the organic dye model, was evaluated. The efficient catalytic activity of Ir-NPs in the reduction of MB by NaBH₄ was demonstrated and Ir-NP2 was prepared using the extract obtained at 65 °C, showing the best catalytic performance, with a rate constant of 0.527 ± 0.012 min^-1 and MB reduction of 96.1% in just six min, with stability for over 10 months.

<i>In Vitro</i> Evaluation of Antibacterial Properties of Biogenically Synthesized Zinc Oxide Nanoparticles on Pathogenic Paddy Bacteria

Zinc oxide nanoparticles (ZnO-NP) were successfully synthesized from aloe vera extract and zinc sulphate as zinc precursor. Characterizations of the ZnO-NP were performed using UV–Vis spectrophotometer, XRD, FESEM and TEM analysis. The absorption peak from UV–Vis was at 380 nm while the XRD diagram displays high purity ZnO-NP. FESEM and TEM analysis showed agglomerated particles with a wide size distribution range. Polymerase chain reaction (PCR) analysis of Xanthomonas oryzae pv. oryzae (Xoo) pathotype 0.0 generated a product with the size of 230 bp similar to in silico PCR results, verifying the pathotype on molecular level. Subsequently, the antimicrobial activities of the ZnO-NP against Xoo pathotype 0.0 were assessed. Xoo (108 cfu/ml) were grown in LB broth supplemented with various concentrations of ZnO-NP. Collection of samples were done at 24 hours, 48 hours and 72 hours of incubation, grown on LB agar and observed for bacterial growth. Colony forming unit (cfu/ml) values revealed the number of viable cells decreased with high concentrations of ZnO-NP whereas minimal inhibition was observed at lower ZnO-NP concentrations. At lower bacteria cfu/ml (103 cfu/ml), it was found that at 24 hours incubation, ZnO-NP gave comparable antibacterial effects to commercial ZnO-NP and commercial non-nanoZnO after exposure for 1 hour. However, the antimicrobial effects decreased after 48 hours. It was also noted that the ZnO-NP provide better suppression of bacterial growth at lower bacterial concentration.

Ziziphus spina-christi extract-stabilized novel silver nanoparticle synthesis for combating Fusarium oxysporum-causing pepper wilt disease: in vitro and in vivo studies

The novelty of the present study is studying the ability of aqueous Ziziphus spina-christi leaves' extract (ZSCE) to produce eco-friendly and cost-effective silver nanoparticles (Ag NPs) against Fusarium wilt disease. Phytochemical screening of ZSCE by HPLC showed that they contain important antimicrobial substances such as Rutin, Naringin, Myricetin, Quercetin, Kaempferol, Hesperidin, Syringeic, Eugenol, Pyrogallol, Gallic and Ferulic. Characterization methods reveal a stable Ag NPs with a crystalline structure, spherical in shape with average particle size about 11.25 nm. ZSCE and Ag NPs showed antifungal potential against F. oxysporum at different concentrations with MIC of Ag NPs as 0.125 mM. Ag NPs treatment was the most effective, as it gave the least disease severity (20.8%) and the highest protection rate (75%). The application of ZSCE or Ag NPs showed a clear recovery, and its effectiveness was not limited for improving growth and metabolic characteristics only, but also inducing substances responsible for defense against pathogens and activating plant immunity (such as increasing phenols and strong expression of peroxidase and polyphenol oxidase as well as isozymes). Owing to beneficial properties such as antifungal activity, and the eco-friendly approach of cost and safety, they can be applied in agricultural field as novel therapeutic nutrients.

Chitosan coated - biogenic silver nanoparticles from wheat residues as green antifungal and nanoprimig in wheat seeds

In this study, chitosan-coated biogenic silver nanoparticles (AgNP-CH) were obtained through green chemistry by recycling wheat crop leaf residues. The nanoparticles were characterized by UV-VIS spectroscopy, and total reflectance-Fourier transform infrared spectroscopy confirmed the nanoparticle formation, and the incorporation of chitosan surrounding silver nanoparticles. The size and morphology of nanoparticles were evaluated by microscopy techniques, showing a size range of 2-10 nm, with spherical shape and narrow distribution. The antifungal assay indicated a higher antimicrobial activity showing values of minimum inhibitory concentrations of 41.7 μg/mL against Fusarium oxysporum, and 208.37 μg/mL for Aspergillus niger, A. versicolor and A. brasiliensis. Finally, non-phytotoxic effects were observed in germination assays at early plant stage of development, and an increase in chlorophyll levels were observed at the doses tested with AgNP-CH. Thus, the use of AgNP-CH could be a potential alternative for the prevention of fungal infections in cereals in the early stages of wheat crop development.

Green synthesized silver nanoparticles from eucalyptus leaves can enhance shelf life of banana without penetrating in pulp

Bananas are exposed to serious post-harvest problems resulting in agricultural and economic losses across the world. The severity of problem is linked with the process of rapid ripening and pathogens attack. Such problems have led to economic losses as well as a lower yield of nutritionally rich bananas. The global demand to increase the life span of bananas and their protection from pathogens-borne diseases urged the use of antimicrobial edible coatings of nanoparticles. The present experiment has explored the innovative development of green synthesized nanoparticles from Eucalyptus leaf extract (ELE) to increase the shelf life of bananas up to 32 days from the day of collection. Statistically significant results were recorded (P = 0.05) by applying five different concentrations of silver nanoparticles (AgNPs) in ranges of 0.01-0.05%. Various morphological and physiological parameters such as color, decay, firmness, weight loss, pulp to peel ratio, pH, titrable acidity (TA), phenolic contents, protein estimation, ethylene production, starch content and total soluble sugars were measured in Cavendish banana (Basrai). Bananas treated with 0.01% AgNPs showed maximum control on its ripeness over morphological and physiological changes. The increase in shelf life was in order 0.01%>0.02%>0.03%>0.04%>0.05%> control. Further, AgNPs reduced the process of ripening by controlling ethylene production. The result has also proved the safety of banana consumption by simple removal of banana peel as penetration of AgNPs from the peel to the pulp was not detected. It is recommended to use 0.01% AgNPs to enhance the shelf life of banana without effecting its nutritive value.

Myconanoparticles Break Antibiotic Resistance in Staphylococcus aureus and Acinetobacter baumannii

In this current study, the extracts of endophytic fungi (Aspergillus niger) were utilized to synthesize the silver nanoparticles (AnNps). In silico screening was carried out by docking secondary metabolites of Aspergillus niger with drug-resistant proteins such as penicillin-binding protein (pbp2a) and clumping factor A of Staphylococcus aureus, penicillin-binding protein (PBP3), and outer membrane protein of Acinetobacter baumannii. The molecular docking analysis revealed the interaction between secondary metabolites of Aspergillus niger with virulence factors of the pathogenic bacteria. AnNps are characterized by various physicochemical methods to determine the size, shape, and stability. Antibacterial efficacy of synthesized nanoparticles (AnNps) was screened in clinical pathogens. AnNp treatment significantly reduced the growth of MDR pathogens. The results suggested that AnNps can be incorporated to produce antimicrobial agents to control drug resistant pathogenic bacteria.

Antibacterial activity of nano zinc oxide green-synthesised from Gardenia thailandica triveng. Leaves against Pseudomonas aeruginosa clinical isolates: in vitro and in vivo study

The increasing emergence of bacterial resistance is a challenge for the research community, thus novel antibacterial agents should be developed. Metal nanoparticles are promising antibacterial agents and could solve the problem of antibiotic resistance. Herein, we used Gardenia thailandica methanol extract (GTME) to biogenically synthesise zinc oxide nanoparticles (ZnO-NPs). The characterisation of ZnO-NPs was performed by UV spectroscopy, FTIR, scanning and transmission electron microscopes, dynamic light scattering, and X-ray diffraction. The antibacterial activity of ZnO-NPs was studied both in vitro and in vivo against Pseudomonas aeruginosa clinical isolates. Its minimum inhibitory concentration values ranged from 2 to 64 µg/mL, and it significantly decreased the membrane integrity and resulted in a significant increase in the inner and outer membrane permeability. Also, the ZnO-NPs treated cells possessed a distorted and deformed shape when examined by scanning electron microscope. The in vivo study (biochemical parameters and histological investigation) was conducted and it revealed a protective effect of ZnO-NPs against the deleterious influences of P. aeruginosa bacteria on lung, liver, and kidney tissues. LC-ESI-MS/MS revealed a phytochemical tentative identification of 57 compounds for the first time. We propose that GTME is a useful source for ZnO-NPs which has a promising antibacterial activity.

Role of AuNPs in Active Food Packaging Improvement: A Review

There is a worldwide concern about food loss due to reduced shelf life among food science researchers. Hence, it seems that any techniques contributing to improved food packaging are most welcome in the food sector. It has been demonstrated that the administration of nanotechnology-based techniques such as metal-based nanoparticles can fade away the unresolved obstacles in shortened shelf life and environmental concerns. Along with substantial signs of progress in nanoscience, there is a great interest in the usage of green synthesis-based methods for gold nanoparticles as the most advantageous metals, when compared to conventional chemistry-based methods. Interestingly, those aforementioned methods have significant potential to simplify targeted administration of gold nanoparticles due to a large surface-volume ratio, and diminished biohazards, aimed at increasing stability, and induction of anti-microbial or antioxidant properties. However, it is necessary to consider the hazards of gold nanoparticles including migration for food packaging purposes.

Mycosynthesis of Metal-Containing Nanoparticles-Fungal Metal Resistance and Mechanisms of Synthesis

In the 21st century, nanomaterials play an increasingly important role in our lives with applications in many sectors, including agriculture, biomedicine, and biosensors. Over the last two decades, extensive research has been conducted to find ways to synthesise nanoparticles (NPs) via mediation with fungi or fungal extracts. Mycosynthesis can potentially be an energy-efficient, highly adjustable, environmentally benign alternative to conventional physico-chemical procedures. This review investigates the role of metal toxicity in fungi on cell growth and biochemical levels, and how their strategies of resistance, i.e., metal chelation, biomineral formation, biosorption, bioaccumulation, compartmentalisation, and efflux of metals from cells, contribute to the synthesis of metal-containing NPs used in different applications, e.g., biomedical, antimicrobial, catalytic, biosensing, and precision agriculture. The role of different synthesis conditions, including that of fungal biomolecules serving as nucleation centres or templates for NP synthesis, reducing agents, or capping agents in the synthesis process, is also discussed. The authors believe that future studies need to focus on the mechanism of NP synthesis, as well as on the influence of such conditions as pH, temperature, biomass, the concentration of the precursors, and volume of the fungal extracts on the efficiency of the mycosynthesis of NPs.

Biosynthesized metal oxide nanoparticles for sustainable agriculture: next-generation nanotechnology for crop production, protection and management

The current agricultural sector is not only in its most vulnerable state but is also becoming a threat to our environment due to expanding population and growing food demands along with worsening climatic conditions. In addition, numerous agrochemicals presently being used as fertilizers and pesticides have low efficiency and high toxicity. However, the rapid growth of nanotechnology has shown great promise to tackle these issues replacing conventional agriculture industries. Since the last decade, nanomaterials especially metal oxide nanoparticles (MONPs) have been attractive for improving agricultural outcomes due to their large surface area, higher chemical/thermal stability and tunable unique physicochemical characteristics. Further, to achieve sustainability, researchers have been extensively working on ecological and cost-effective biological approaches to synthesize MONPs. Hereby, we have elaborated on recent successful biosynthesis methods using various plants/microbes. Furthermore, we have elucidated different mechanisms for the interaction of MONPs with plants, including their uptake/translocation/internalization, photosynthesis, antioxidant activity, and gene alteration, which could revolutionize crop productivity/yield through increased nutrient amount, photosynthesis rate, antioxidative enzyme level, and gene upregulations. Besides, we have briefly discussed about functionalization of MONPs and their application in agricultural-waste-management. We have further illuminated recent developments of various MONPs (Fe₂O₃/ZnO/CuO/Al₂O₃/TiO₂/MnO₂) as nanofertilizers, nanopesticides and antimicrobial agents and their implications for enhanced plant growth and pest/disease management. Moreover, the potential use of MONPs as nanobiosensors for detecting nutrients/pathogens/toxins and safeguarding plant/soil health is also illuminated. Overall, this review attempts to provide a clear insight into the latest advances in biosynthesized MONPs for sustainable crop production, protection and management and their scope in the upcoming future of eco-friendly agricultural nanotechnology.

Leucophyllum frutescens mediated synthesis of silver and gold nanoparticles for catalytic dye degradation

The application of nanotechnology is gaining worldwide attention due to attractive physico-chemical and opto-electronic properties of nanoparticles that can be also employed for catalytic dye degradation. This study reports a phytogenic approach for fabrication of silver (AgNPs) and gold nanoparticles (AuNPs) using Leucophyllum frutescens (Berl.) I. M. Johnst (Scrophulariaceae) leaf extract (LFLE). Development of intense dark brown and purple color indicated the synthesis of AgNPs and AuNPs, respectively. Further characterization using UV-visible spectroscopy revealed sharp peak at 460 nm and 540 nm for AgNPs and AuNPs, respectively that were associated to their surface plasmon resonance. High resolution transmission electron microscope (HRTEM) revealed the spherical shape of the AgNPs, whereas anisotropic AuNPs were spherical, triangular and blunt ended hexagons. The majority of the spherical AgNPs and AuNPs were ∼50 ± 15 nm and ∼22 ± 20 nm, respectively. Various reaction parameters such as, metal salt concentration, temperature and concentration of the leaf extract were optimized. Maximum synthesis of AgNPs was obtained when 5 mM for AgNO₃ reacted with 10% LFLE for 48 h at 50°C. Likewise, AuNPs synthesis was highest when 2 mM HAuCl₄ reacted with 10% LFLE for 5 h at 30°C. Energy dispersive spectroscopy (EDS) showed phase purity of both the nanoparticles and confirmed elemental silver and gold in AgNPs and AuNPs, respectively. The average hydrodynamic particles size of AgNPs was 34.8 nm while AuNPs was 140.8 nm as revealed using dynamic light scattering (DLS) that might be due to agglomeration of smaller nanoparticles into larger clusters. ZETA potential of AgNPs and AuNPs were 0.67 mV and 5.70 mV, respectively. X-ray diffraction (XRD) analysis confirmed the crystallinity of the nanoparticles. Fourier transform infrared spectroscopy (FTIR) confirmed that various functional groups from the phytochemicals present in LFLE played a significant role in reduction and stabilization during the biogenic synthesis of the nanoparticles. The bioreduced AgNPs and AuNPs catalytically degraded Rhodamine B dye (RhB) in presence of UV-light with degradation rate constants of 0.0231 s⁻¹ and 0.00831 s⁻¹, respectively. RhB degradation followed a first order rate kinetics with 23.1 % and 31.7% degradation by AgNPs and AuNPs, respectively.

Green synthesized silver nanoparticles: Optimization, characterization, antimicrobial activity, and cytotoxicity study by hemolysis assay

Green nanotechnology has emerged as a viable option for the production of nanoparticles. The purpose of the current investigation was to synthesize silver nanoparticles (AgNPs) using Eucalyptus camaldulensis and Terminalia arjuna extracts, as well as their combinations, as green reducing and capping agents. The parameters (concentration of silver nitrate solution and plant extract, time, pH, and temperature) were optimized for maximal yields, regulated size, and stability of silver nanoparticles. The ultraviolet–visible spectrophotometer (UV-Vis) and the surface plasmon resonance band (SPR) were used to validate the synthesis of AgNPs. The size, shape, and stability of nanoparticles were assessed using a zeta analyzer and a scanning electron microscope (SEM). The biomolecules responsible for the reduction of silver ion (Ag⁺) and the stability of silver nanoparticles generated with the plant extracts were identified using Fourier-transform infrared spectroscopy (FTIR). The agar-well diffusion method was used to test the antimicrobial activity of biosynthesized nanoparticles against Bacillus subtilis, Staphylococcus aureus, Pasteurella multocida, and Escherichia coli. When 1 mM of silver nitrate (AgNO₃) was added to plant extracts and incubated for 60 min at 75°C in a neutral medium, maximum nanoparticles were produced. Biosynthesized silver nanoparticles were stable, spherical, and monodispersed according to zeta potential and scanning electron microscopy. Silver nanoparticles synthesized with combination 2 and T. arjuna showed the highest zone of inhibition (16 mm) against B. subtilis while combination 3 showed the largest zone of inhibition against S. aureus (17 ± 0.8). It was concluded that greenly produced silver nanoparticles showed good antibacterial activity while causing negligible cytotoxicity.

Green, Sustainable Synthesis of γ-Fe2O3/MWCNT/Ag Nano-Composites Using the Viscum album Leaf Extract and Waste Car Tire for Removal of Sulfamethazine and Bacteria from Wastewater Streams

Multi-walled carbon nanotubes (MWCNTs) decorated with Ag nanoparticles (NPs) are bifunctional adsorbent nanomaterials with antibacterial activity. They can be magnetically recovered from wastewater in case of coupling with γ-Fe₂O₃. In this study, for the first time, an environmentally friendly technique was applied to prepare a nanocomposite (NC) material composed of γ-Fe₂O₃/MWCNT/Ag by using Bridgestone disposable tires and Viscum album leaves extract. γ-Fe₂O₃/MWCNTs/Ag NC was employed for the removal of sulfamethazine (SMT) from aqueous solutions. Under the optimized conditions determined via the Taguchi method, the highest SMT adsorption capacity of the γ-Fe₂O₃/MWCNT/Ag NC was measured to be 47.6 mg/g. The experimental data fitted well with the pseudo-second-order kinetic model and the Langmuir isotherm. The thermodynamic parameters implied that the adsorption process was endothermic. In addition to adsorption of the drug pollutant, the NC demonstrated a superior antibacterial activity against Gram-positive bacteria. The reusability test also showed that over 79% SMT can be removed using γ-Fe₂O₃/MWCNTs/Ag NC even after four adsorption cycles. Taken together, γ-Fe₂O₃/MWCNTs/Ag NC was proven to be a promising antibacterial nano-adsorbent for wastewater treatment.

An improved surface enhanced Raman spectroscopic method using a paper-based grape skin-gold nanoparticles/graphene oxide substrate for detection of rhodamine 6G in water and food

Organic toxins are persistent chemicals of global concern capable of accumulating in environment and food. Surface enhanced Raman spectroscopy (SERS) is a promising technique that facilitates onsite detection of organic toxins. However, the fabrication of a SERS substrate is complicated and difficult to provide flexibility, fastness and cost-effectiveness. This study aims to develop a paper-based SERS method using grape skin-gold nanoparticles/graphene oxide (GE-AuNPs/GO) as SERS substrate and evaluate its efficiency with rhodamine 6G (Rh6G) as a model organic toxin and a real water and food contaminant. GE-AuNPs synthesized by green method using grape skin waste extract and GE-AuNPs/GO showed a surface plasmon resonance at 536 and 539 nm, particle size 18.6 and 19.5 nm, and zeta potential -44.6 and -59.7 mV, respectively. Paper-based SERS substrates were prepared by coating a hydrophobic thin-film of 30% polydimethylsiloxane solution in hexane on Whatman no. 1 filter paper, followed by drop-casting GE-AuNPs or GE-AuNPs/GO and drying. The SERS signals of Rh6G showed an enhancement factor of 5.8 × 10⁴ for GE-AuNPs and 1.92 × 10⁹ for GE-AuNPs/GO, implying that a combination of electromagnetic surface plasmon, charge transfer and molecular resonances may be responsible for a higher enhancement of signal by the latter. A low detection limit of 7.33 × 10^-11 M in the linear range of 10^-11-10^-5 M was obtained for GE-AuNPs/GO, while the relative standard deviation of repeatability and reproducibility was 9.6 and 12.6%, respectively. Paper-based GE-AuNPs/GO SERS substrate was highly stable as <20% loss in efficiency was shown over a 60-day storage period. Application to real samples showed a high recovery of Rh6G from tap water (93.9-100.8%) as well as food samples such as red chilli powder (91.0-95.4%), red glutinous rice ball (96.6-98.3%) and tomato ketchup (98.9-102.3%) after QuEChERS extraction. Collectively, the developed paper-based GE-AuNPs/GO can be a potential substrate for sensitive onsite detection of rhodamine 6G by SERS method.