Plant-mediated synthesis of nanoparticles and their antimicrobial activity against phytopathogens

Beyond Conventional Antibiotics Approaches: Global Perspectives on Alternative Therapeutics including Herbal Prevention, and Proactive Management Strategies in Bovine mastitis

Mastitis, an intramammary inflammation resulting from microbial infectious agents, continues to pose a significant challenge within the dairy sector, adversely affecting animal well-being and leading to substantial economic losses. These losses are attributed to decreased milk production, heightened culling rates, and the expenses related to diagnostics, veterinary care, medication, and labor. Moreover, additional costs emerge due to reduced forthcoming milk yields, compromised reproductive health, and increased susceptibility to various illnesses. Identifying the responsible agents is crucial for disease management and the implementation of antimicrobial treatments. Despite the prevalent use of antibiotic treatment, the pressing need for new therapeutic alternatives to combat bovine mastitis arises from limitations, including low cure rates, rising resistance, and the presence of antibiotic residues in milk. This review explores the potential application of herbal extracts and essential oils known for their antimicrobial properties as alternative options for managing pathogens in mastitis treatment. It examines various treatment methods and management strategies, particularly emphasizing the progress of herbal remedies and natural therapeutics in addressing mastitis, a significant concern in bovine populations and dairy herds.

Rethinking Nanoparticle Synthesis: A Sustainable Approach vs. Traditional Methods

This review portrays a comparison between green protocols and conventional nanoparticle (NP) synthesis strategies, highlighting each method's advantages and limitations. Various top-down and bottom-up methods in NP synthesis are described in detail. The green chemistry principles are emphasized for designing safe processes for nanomaterial synthesis. Among the green biogenic sources plant extracts, vitamins, enzymes, polysaccharides, fungi (Molds and mushrooms), bacteria, yeast, algae, and lichens are discussed. Limitations in the reproducibility of green protocols in terms of availability of raw material, variation in synthetic protocol, and selection of material due to geographical differences are elaborated. Finally, a conclusion is drawn utilizing green chemical principles, & a circular economy strategy to minimize waste generation, offering a promising framework for the synthesis of NPs emphasizing sustainability.

Synergetic effects and inhibition mechanisms of the polysaccharide-selenium nanoparticle complex in human hepatocarcinoma cell proliferation

BACKGROUND

Active components from natural fungal products have shown promising potential as anti-tumor therapeutic agents. In the search for anti-tumor agents, research to overcome the drawbacks of high molecular weight and low bioavailability of pure polysaccharides, polysaccharide-conjugated selenium nanoparticles (SeNPs) has attracted much attention.

RESULTS

A novel polysaccharide-selenium nanoparticle complex was produced, in which SeNPs were decorated with polysaccharide obtained from fermented mycelia broth of Lactarius deliciosus (FLDP). Transmission electron microscope, dynamic light scattering, and X-ray photoelectron spectroscopy were utilized to characterize the FLDP-SeNPs; and human hepatocarcinoma cell line (HepG2) was used to assess growth inhibition efficacy. The FLDP-SeNPs that were prepared had a spherical shape with the smallest mean diameter of 32 nm. The FLDP-SeNPs showed satisfactory dispersibility and stability after combination, demonstrating that a reliable consolidated structure had formed. The results revealed that FLDP-SeNPs had notable growth inhibition effects on HepG2 cells. They reduced the membrane potential of mitochondria significantly, increased the generation of reactive oxygen species, enhanced levels of both Caspase-3 and Caspase-9, and led to the nucleus in a wrinkled form.

CONCLUSION

The FLDP-SeNPs could exert a synergetic toxicity reduction and inhibition enhancement effect on HepG2 cells by inducing early apoptosis, through mitochondria-mediated cytochrome C-Caspases and reactive oxygen species-induced DNA damage pathways. These results indicate that FLDP-SeNP treatment of HepG2 cells induced early apoptosis with synergetic efficacy, showing that FLDP-SeNPs can be useful as natural anti-tumor agents. © 2024 Society of Chemical Industry.

Efficient removal of Sb(III) from wastewater using selenium nanoparticles synthesized by Psidium guajava plant extract

Antimony (Sb) pollution in aquatic ecosystems has emerged as a critical environmental issue on a global scale, emphasizing the urgent need for cost-effective and user-friendly technologies to remove Sb compounds from water sources. In this study, a novel adsorbent, selenium nanoparticles (SeNPs), was synthesized using the aqueous extract of Psidium guajava L. leaves (AEP) for the purpose of eliminating Sb(III) from aqueous solutions. The biosynthesized SeNPs was characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray fluorescence spectrometer (XRF), Fourier Transform-Infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) analysis techniques. Additionally, the removal efficiency of the SeNPs for Sb(III) was systematic investigated under the effects of SeNPs dose, temperature, pH and re-usability. The results of this study showed that the adsorption data fitted well into pseudo-second order model, while the Sips modeling demonstrated a high adsorption capacity (62.7 mg/g) of SeNPs for Sb(III) ions at 303.15 K from aqueous solution. The exothermic enthalpy change of - 22.59 kJ/mol and negative Gibbs free energy change assured the viability of the adsorption process under the considered temperature conditions. Surface functional groups on SeNPs like carboxyl, amide, hydroxyl, carbonyl, and methylene significantly facilitate the adsorption processes. Furthermore, the removal efficiencies of Sb in the two actual Sb mine wastewater samples were remarkably high, achieving nearly to 100% with 1.5 g/L SeNPs within 48 h. This outcome underscores the potential of SeNPs as a highly promising solution for efficiently remediating Sb from aquatic environments, owing to their cost-effectiveness, ease of regeneration, and rapid uptake capabilities.

Versatile Ce(III)‐Terephthalic Acid@Au Metal Organic Frameworks for ROS Elimination and Photothermal Sterilization

Nanozymes have been widely used for treating reactive oxygen species (ROS) caused diseases. However, the ROS‐dependent antibacterial property is inevitably damaged during the process of scavenging ROS, which is unfavorable for the treatment of diseases related to both ROS accumulation and bacterial infections. To address the issues, biomedical materials with both ROS‐elimination ability and ROS‐independent antibacterial capacity are fabricated via in situ depositing spherical Au nanoparticles (Au NPs) on rough surface of metal organic frameworks composed of Ce(III) and terephthalic acid (Ce‐BDC@Au MOFs). The synthesized Ce‐BDC@Au MOFs show multi‐enzymatic activities owing to the reversible conversion between Ce3+ and Ce4+, and can significantly scavenge ROS in cells. The deposition of spherical Au NPs on surface of Ce‐BDC MOFs causes Au NPs to come close proximity for forming plasmon resonance coupling, inducing the resonance wavelength of Au NPs red shifted to NIR region. Based on this, Ce‐BDC@Au MOFs show good photothermal conversion efficiency under NIR laser (808 nm) irradiation. Benefitting from rough surface and photothermal conversion ability, Ce‐BDC@Au MOFs have high antibacterial efficiency against staphylococcus aureus through both mechanically damaging and photothermal destruction. This strategy is biosafety and effectiveness for treating diseases related to both ROS accumulation and bacterial infections.

Revolutionizing agriculture with nanotechnology: Innovative approaches in fungal disease management and plant health monitoring

Nanotechnology has emerged as a transformative force in modern agriculture, offering innovative solutions to address challenges related to fungal plant diseases and overall agricultural productivity. Specifically, the antifungal activities of metal, metal oxide, bio-nanoparticles, and polymer nanoparticles were examined, highlighting their unique mechanisms of action against fungal pathogens. Nanoparticles can be used as carriers for fungicides, offering advantages in controlled release, targeted delivery, and reduced environmental toxicity. Nano-pesticides and nano-fertilizers can enhance nutrient uptake, plant health, and disease resistance were explored. The development of nanosensors, especially those utilizing quantum dots and plasmonic nanoparticles, promises early and accurate detection of fungal pathogens, a crucial step in timely disease management. However, concerns about their potential toxic effects on non-target organisms, environmental impacts, and regulatory hurdles underscore the importance of rigorous research and impact assessments. The review concludes by emphasizing the significant prospects of nanotechnology in reshaping the future of agriculture but advocates for a balanced approach that prioritizes safety, sustainability, and environmental stewardship.

Integrative transcriptomic and metabolomic analyses reveals the toxicity and mechanistic insights of bioformulated chitosan nanoparticles against Magnaporthe oryzae

Rice blast, an extremely destructive disease caused by the filamentous fungal pathogen Magnaporthe oryzae, poses a global threat to the production of rice (Oryza sativa L.). The emerging trend of reducing dependence on chemical fungicides for crop protection has increased interest in exploring bioformulated nanomaterials as a sustainable alternative antimicrobial strategy for effectively managing plant diseases. Herein, we used physiomorphological, transcriptomic, and metabolomic methods to investigate the toxicity and molecular action mechanisms of moringa-chitosan nanoparticles (M-CNPs) against M. oryzae. Our results demonstrate that M-CNPs exhibit direct antifungal properties by impeding the growth and conidia formation of M. oryzae in a concentration-dependent manner. Propidium iodide staining indicated concentration-dependent significant apoptosis (91.33%) in the fungus. Ultrastructural observations revealed complete structural damage in fungal cells treated with 200 mg/L M-CNPs, including disruption of the cell wall and destruction of internal organelles. Transcriptomic and metabolomic analyses revealed the intricate mechanism underlying the toxicity of M-CNPs against M. oryzae. The transcriptomics data indicated that exposure to M-CNPs disrupted various processes integral to cell membrane biosynthesis, aflatoxin biosynthesis, transcriptional regulation, and nuclear integrity in M. oryzae., emphasizing the interaction between M-CNPs and fungal cells. Similarly, metabolomic profiling demonstrated that exposure to M-CNPs significantly altered the levels of several key metabolites involved in the integral components of metabolic pathways, microbial metabolism, histidine metabolism, citrate cycle, and lipid and protein metabolism in M. oryzae. Overall, these findings demonstrated the potent antifungal action of M-CNPs, with a remarkable impact at the physiological and molecular level, culminating in substantial apoptotic-like fungal cell death. This research provides a novel perspective on investigating bioformulated nanomaterials as antifungal agents for plant disease control.

Antimicrobial activity of probiotic bacteria-mediated cadmium oxide nanoparticles against fish pathogens

The current research was designed to investigate the antibacterial activity of probiotic bacteria mediated cadmium oxide nanoparticles (CdO NPs) on common fish pathogenic bacteria like Serratia marcescens, Aeromonas hydrophila, Vibrio harveyi, and V. parahaemolyticus. CdO NPs were synthesized using probiotic bacteria as follows: Lactobacillus species with different precursor of cadmium sulfate concentrations (5, 10, and 20 mM). The average crystalline sizes of the CdO NPs were determined based on the XRD patterns using the Debye-Scherrer equation for different precursor concentrations. Specifically, sizes of 40, 48, and 67 nm were found at concentrations of 5, 10, and 20 mM, respectively. The antibacterial efficacy of CdO NPs was estimated using a well diffusion assay, which demonstrated the best efficacy of 20 mM CdO NPs against all pathogens. AFM analysis of nanoparticle-treated and untreated biofilms was performed to further validate the antibacterial effect. Antibacterial activity of CdO nanoparticles synthesized at varying concentrations (5, 10, and 20 mM) against fish pathogens (S. marcescens, A. hydrophila, V. harveyi, and V. parahaemolyticus). The results indicated the highest inhibitory effect of 20 mM CdO NPs across all concentrations (30, 60, and 90 μg/mL), demonstrating significant inhibition against S. marcescens. These findings will contribute to the development of novel strategies for combating aquatic diseases and advancing aquaculture health management practices.

Biosynthesis of palladium, platinum, and their bimetallic nanoparticles using rosemary and ginseng herbal plants: evaluation of anticancer activity

In this research, palladium (II) and platinum (II), as well as their bimetallic nanoparticles were synthesized using medicinal plants in an eco-friendly manner. Rosemary and Ginseng extracts were chosen due to their promising anticancer potential. The synthesized nanoparticles underwent characterization through FT-IR spectroscopy, DLS, XRD, EDX, SEM, and TEM techniques. Once the expected structures were confirmed, the performance of these nanoparticles, which exhibited an optimal size, was evaluated as potential anticancer agents through in vitro method on colon cancer cell lines (Ls180, SW480). MTT assay studies showed that the synthesized nanoparticles induced cell death. Moreover, real-time PCR was employed to investigate autophagy markers and the effect of nanoparticles on the apoptosis process, demonstrating a significant effect of the synthesized compounds in this regard.

Biogenic synthesis of silver nanoparticles using Rubus fruticosus extract and their antibacterial efficacy against Erwinia caratovora and Ralstonia solanacearum phytopathogens

In the current research, we produced green, cost-effective, eco-friendly silver nanoparticles using a single-step approach. Plants are considered highly desirable systems for nanoparticle synthesis because they possess a variety of secondary metabolites with significant reduction potential. In the current research, the dried leaf extract of Rubus fruticosus was utilized as a capping and reducing agent for the fabrication of silver nanoparticles, to prepare reliable biogenic silver nanoparticles and subsequently to investigate their potential against some common phytopathogens. The prepared silver nanoparticles were exploited to quantify the total flavonoid content (TFC), total phenolic content (TPC) and DPPH-based antioxidant activity. Different concentrations of aqueous extracts of plant leaves and silver nitrate (AgNO3) were reacted, and the color change of the reactant mixture confirmed the formation of Rubus fruticosus leaf-mediated silver nanoparticles (RFL-AgNPs). A series of characterization techniques such as UV-vis spectroscopy, transmission electron microscopy, energy dispersive X-ray analysis and X-ray diffraction revealed the successful synthesis of silver nanoparticles. The surface plasmon resonance peak appeared at 449 nm. XRD analysis demonstrated the crystalline nature, EDX confirmed the purity, and TEM demonstrated that the nanoparticles are mostly spherical in form. Furthermore, the biosynthesized nanoparticles were screened for in vitro antibacterial activity, antioxidant activity, and total phenolic and flavonoid content. The nanoparticles were used in different concentrations alone and in combination with plant extracts to inhibit Erwinia caratovora and Ralstonia solanacearum. In high-throughput assays used to inhibit these plant pathogens, the nanoparticles were highly toxic against bacterial pathogens. This study can be exploited for planta assays against phytopathogens utilizing the same formulations for nanoparticle synthesis and to develop potent antibacterial agents to combat plant diseases.

Green-synthesized silver nanoparticles from Zingiber officinale extract: antioxidant potential, biocompatibility, anti-LOX properties, and in silico analysis

INTRODUCTION

Zingiber officinale extract has emerged as a compelling candidate for green synthesis of nanoparticles, offering diverse applications across medicine, cosmetics, and nutrition. This study delves into the investigation of in vitro toxicity and explores the biomedical utility of green-synthesized silver nanoparticles derived from ginger extract (GE-AgNPs).

METHODS

We employed established protocols to evaluate in vitro aspects such as antioxidant capacity, anti-inflammatory potential, and biocompatibility of GE-AgNPs. Additionally, molecular docking was employed to assess their anti-lipoxygenase (anti-LOX) activity.

RESULTS

Our findings highlight that the extraction of ginger extract at a pH of 6, utilizing a cosolvent blend of ethanol and ethyl acetate in a 1:1 ratio, yields heightened antioxidant capacity attributed to its rich phenolic and flavonoid content. In the context of silver nanoparticle synthesis, pH 6 extraction yields the highest quantity of nanoparticles, characterized by an average size of 32.64 ± 1.65 nm. Of particular significance, GE-AgNPs (at pH 6) demonstrated remarkable efficacy in scavenging free radicals, as evidenced by an IC50 value of 6.83 ± 0.47 µg/mL. The results from the anti-LOX experiment indicate that GE-AgNPs, at a concentration of 10 µg/mL, can inhibit LOX activity by 25%, outperforming ginger extract which inhibits LOX by 17-18%. Notably, clionasterol exhibited higher binding energy and enhanced stability (-8.9 kcal/mol) compared to nordihydroguaiaretic acid. Furthermore, a cell viability study confirmed the safety of GE-AgNPs at a concentration of 17.52 ± 7.00 µg/mL against the L929 cell line.

CONCLUSION

These comprehensive findings underscore the significant biomedical advantages of GE-AgNPs and emphasize their potential incorporation into cosmetic products at a maximum concentration of 10 µg/mL.

Utilizing Cymbopogon Proximus Grass Extract for Green Synthesis of Zinc Oxide Nanorod Needles in Dye Degradation Studies

This study successfully synthesized zinc oxide nanorod needles (ZnO-NRNs) using an environmentally friendly method employing Cymbopogon Proximus extract. The resulting ZnO-NRNs exhibited exceptional physicochemical and structural properties, confirmed through various characterization techniques, including UV-Vis spectrophotometry, dynamic light scattering (DLS), transmission electron microscopy (TEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDX). The analysis revealed a hexagonal wurtzite structure with high crystallinity, a 3.6 eV band gap, and a notably blue-shifted absorption band. ZnO-NRNs showed impressive photocatalytic activity, degrading Rhodamine B dye by 97% under UV and visible sunlight, highlighting their photostability and reusability. This green synthesis process offers cost effectiveness and environmental sustainability for practical applications.

An overview of green synthesized silver nanoparticles towards bioactive antibacterial, antimicrobial and antifungal applications

Present review emphatically introduces the synthesis, biocompatibility, and applications of silver nanoparticles (AgNPs), including their antibacterial, antimicrobial, and antifungal properties. A comprehensive discussion of various synthesis methods for AgNPs, with a particular focus on green chemistry mediated by plant extracts has been made. Recent research has revealed that the optical properties of AgNPs, including surface plasmon resonance (SPR), depend on the particle size, as well as the synthesis methods, preparation synthesis parameters, and used reducing agents. The significant emphasis on the use of synthesized AgNPs as antibacterial, antimicrobial, and antifungal agents in various applications has been reviewed. Furthermore, the application areas have been thoroughly examined, providing a detailed discussion of the underlying mechanisms, which aids in determining the optimal control parameters during the synthesis process of AgNPs. Furthermore, the challenges encountered while utilizing AgNPs and the corresponding advancements to overcome them have also been addressed. This review not only summarizes the achievements and current status of plant-mediated green synthesis of AgNPs but also explores the future prospects of these materials and technology in diverse areas, including bioactive applications.

Therapeutic potential and pharmacological significance of extracellular vesicles derived from traditional medicinal plants

Medicinal plants are the primary sources for the discovery of novel medicines and the basis of ethnopharmacological research. While existing studies mainly focus on the chemical compounds, there is little research about the functions of other contents in medicinal plants. Extracellular vesicles (EVs) are functionally active, nanoscale, membrane-bound vesicles secreted by almost all eukaryotic cells. Intriguingly, plant-derived extracellular vesicles (PDEVs) also have been implicated to play an important role in therapeutic application. PDEVs were reported to have physical and chemical properties similar to mammalian EVs, which are rich in lipids, proteins, nucleic acids, and pharmacologically active compounds. Besides these properties, PDEVs also exhibit unique advantages, especially intrinsic bioactivity, high stability, and easy absorption. PDEVs were found to be transferred into recipient cells and significantly affect their biological process involved in many diseases, such as inflammation and tumors. PDEVs also could offer unique morphological and compositional characteristics as natural nanocarriers by innately shuttling bioactive lipids, RNA, proteins, and other pharmacologically active substances. In addition, PDEVs could effectively encapsulate hydrophobic and hydrophilic chemicals, remain stable, and cross stringent biological barriers. Thus, this study focuses on the pharmacological action and mechanisms of PDEVs in therapeutic applications. We also systemically deal with facets of PDEVs, ranging from their isolation to composition, biological functions, and biotherapeutic roles. Efforts are also made to elucidate recent advances in re-engineering PDEVs applied as stable, effective, and non-immunogenic therapeutic applications to meet the ever-stringent demands. Considering its unique advantages, these studies not only provide relevant scientific evidence on therapeutic applications but could also replenish and inherit precious cultural heritage.

Development, Characterization, and Antibacterial Analysis of the Selenium-Doped Bio-Glass-Collagen-Gelatin Composite Scaffold for Guided Bone Regeneration

Background Guided bone regeneration (GBR) is an often-used technique to aid the successful placement of dental implants in sites with deficient bone. The search for the ideal GBR membrane with bioactive components improving the regenerative outcomes is still on. In this study, a novel composite GBR membrane was developed using selenium-doped bio-glass, collagen, and gelatin. It was further characterized for surface, chemical, biocompatibility, and antibacterial properties. Methodology Selenium-doped bio-glass was prepared using the sol-gel method. The membrane was fabricated using an equal ratio of collagen and gelatin mixed with 1% selenium-doped bio-glass. The solution was poured to obtain a thin layer of the material which was lyophilized to obtain the final GBR membrane. The membrane was analyzed with scanning electron microscopy, energy dispersive X-ray (EDX) analysis, attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), zebrafish cytotoxicity test, and antibacterial assay. Results The membrane revealed good surface roughness with lamellar and fibrillar arrangement with a minute granular surface ideal for cell attachment and proliferation. The EDX analysis revealed the presence of carbon, oxygen, and nitrogen as predominant components with trace amounts of calcium, phosphorus, silica, and selenium. Fourier transform infrared spectroscopy analysis also proved the presence of collagen, gelatin, and bio-glass. The membrane revealed excellent biocompatibility with zebrafish growth at a normal rate with 90% viability maintained at 48, 72, and 96 hours and 95% viability at 120 hours. It also exhibited excellent antibacterial activity against Staphylococcus aureus and Escherichia coli with minimal growth of bacterial colonies. Conclusion The developed novel selenium bio-glass collagen and gelatin composite scaffold has a good surface and antibacterial properties along with excellent biocompatibility. Further cell line and in vivo studies should be conducted to explore its role in bone regeneration.

Selenium nanoparticles based on Amphipterygium glaucum extract with antibacterial, antioxidant, and plant biostimulant properties

BACKGROUND

In recent years, crop production has expanded due to the variety of commercially available species. This increase in production has led to global competition and the search for biostimulant products that improve crop quality and yield. At the same time, agricultural products that protect against diseases caused by phytopathogenic microorganisms are needed. Thus, the green synthesis of selenium nanoparticles (SeNPs) is a proposal for achieving these needs. In this research, SeNPs were synthesized from methanolic extract of Amphipterygium glaucum leaves, and chemically and biologically characterized.

RESULTS

The characterization of SeNPs was conducted by ultraviolet-visible spectrophotometry (UV-Vis), scanning electron microscopy (SEM), electron microscopy transmission (TEM), Dynamic Light Scattering (DLS), energy dispersion X-ray spectroscopy (EDX), and infrared spectrophotometry (FTIR) techniques. SeNPs with an average size of 40-60 nm and spherical and needle-shaped morphologies were obtained. The antibacterial activity of SeNPs against Serratia marcescens, Enterobacter cloacae, and Alcaligenes faecalis was evaluated. The results indicate that the methanolic extracts of A. glaucum and SeNPs presented a high antioxidant activity. The biostimulant effect of SeNPs (10, 20, 50, and 100 µM) was evaluated in vinca (Catharanthus roseus), and calendula (Calendula officinalis) plants under greenhouse conditions, and they improved growth parameters such as the height, the fresh and dry weight of roots, stems, and leaves; and the number of flowers of vinca and calendula.

CONCLUSIONS

The antibacterial, antioxidant, and biostimulant properties of SeNPs synthesized from A. glaucum extract demonstrated in this study support their use as a promising tool in crop production.

Characterization of Silver Nanoparticles Synthesized by the Aqueous Extract of Zanthoxylum nitidum and Its Herbicidal Activity against Bidens pilosa L

Phytosynthesis of silver nanoparticles (Ag NPs) has been progressively acquiring attractiveness. In this study, the root of Zanthoxylum nitidum was used to synthesize Ag NPs, and its pre-emergence herbicidal activity was tested. The synthesized Ag NPs by the aqueous extract from Z. nitidum were characterized by visual inspection, ultraviolet-visible spectroscopy, dynamic light scattering (DLS), X-ray diffraction (XRD), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX). The plant-mediated synthesis was completed within 180 min and the Ag NPs exhibited a characteristic peak at around 445 nm. The results of the DLS measurement showed that the average hydrodynamic diameter was 96 nm with a polydispersity index (PDI) of 0.232. XRD results indicated the crystalline nature of the phytogenic Ag NPs. A TEM analysis revealed that the nanoparticles were spherical with an average particle size of 17 nm. An EDX spectrum confirmed the presence of an elemental silver signal. Furthermore, the Ag NPs exhibited a herbicidal potential against the seed germination and seedling growth of Bidens Pilosa L. The present work indicates that Ag NPs synthesized by plant extract could have potential for the development of a new nanoherbicide for weed prevention and control.

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.

Synergistic impact of nanomaterials and plant probiotics in agriculture: A tale of two-way strategy for long-term sustainability

Modern agriculture is primarily focused on the massive production of cereals and other food-based crops in a sustainable manner in order to fulfill the food demands of an ever-increasing global population. However, intensive agricultural practices, rampant use of agrochemicals, and other environmental factors result in soil fertility degradation, environmental pollution, disruption of soil biodiversity, pest resistance, and a decline in crop yields. Thus, experts are shifting their focus to other eco-friendly and safer methods of fertilization in order to ensure agricultural sustainability. Indeed, the importance of plant growth-promoting microorganisms, also determined as "plant probiotics (PPs)," has gained widespread recognition, and their usage as biofertilizers is being actively promoted as a means of mitigating the harmful effects of agrochemicals. As bio-elicitors, PPs promote plant growth and colonize soil or plant tissues when administered in soil, seeds, or plant surface and are used as an alternative means to avoid heavy use of agrochemicals. In the past few years, the use of nanotechnology has also brought a revolution in agriculture due to the application of various nanomaterials (NMs) or nano-based fertilizers to increase crop productivity. Given the beneficial properties of PPs and NMs, these two can be used in tandem to maximize benefits. However, the use of combinations of NMs and PPs, or their synergistic use, is in its infancy but has exhibited better crop-modulating effects in terms of improvement in crop productivity, mitigation of environmental stress (drought, salinity, etc.), restoration of soil fertility, and strengthening of the bioeconomy. In addition, a proper assessment of nanomaterials is necessary before their application, and a safer dose of NMs should be applicable without showing any toxic impact on the environment and soil microbial communities. The combo of NMs and PPs can also be encapsulated within a suitable carrier, and this method aids in the controlled and targeted delivery of entrapped components and also increases the shelf life of PPs. However, this review highlights the functional annotation of the combined impact of NMs and PPs on sustainable agricultural production in an eco-friendly manner.

Formulation and Evaluation of Quality Parameters of Effervescent Granules from the Potent Antioxidant between Two Variants of the Adaptogenic Herb Ocimum tenuiflorum L

Ocimum tenuiflorum L. is found throughout semitropical and tropical parts of Southeast Asia. In Nepal, O. tenuiflorum L. is popular with two variants: Krishna Tulsi consisting of purple-colored leaves and Sri Tulsi consisting of green-colored leaves. O. tenuiflorum L. is considered the queen of herbs and is a traditionally and clinically proven medicinal herb for its application and efficacy. However, no commercial pharmaceutical preparations of O. tenuiflorum L. are available using effervescent vehicles. Therefore, the present study aimed to compare the antioxidant activity of leaves from the two varieties of O. tenuiflorum L. and formulate and evaluate the quality parameters of effervescent granules of the potent extract. The antioxidant activity of O. tenuiflorum L. ethanolic extracts was evaluated by DPPH radical scavenging assay at 1, 10, and 100 µg/mL concentrations, where ascorbic acid was used as the positive control. The antioxidant activity of purple-leafed O. tenuiflorum L. was found to be higher than that of green-leafed O. tenuiflorum L. Therefore, effervescent granules of the ethanolic extract of purple-leafed O. tenuiflorum L. were formulated using the pharmaceutical excipients tartaric acid, citric acid, and sodium bicarbonate and the quality parameters of the granules were evaluated. The formulated granules met the quality parameters assessed from the angle of repose, bulk density, tapped density, Carr's Index, Hausner's ratio, effervescent cessation time, and stability studies. Thus, the formulated effervescent granules of O. tenuiflorum L. can be used for therapeutic purposes or as a functional food.

Green synthesis and antimicrobial mechanism of nanoparticles: applications in agricultural and agrifood safety

The growing demand for food and its safety are a challenge for agriculture and agrifood. This has led to the incorporation of alternatives such as organic agriculture, the use of biocontrollers, the development of transgenic plants resistant to pathogens and the incorporation of nanotechnology. In this sense, agrochemicals based on nanoparticles (NPs) have been developed. Recently, the green synthesis of NPs has grown rapidly and, for this reason, molecules, microorganisms, fungi and plants are used. Synthesis from plant extracts offers a broad spectrum and, despite the fact that NPs are usually dispersed in size and shape, extensive antimicrobial effectiveness has been demonstrated at nanomolar concentrations. It has been shown that the mechanism of action can be through the dissipation of the driving force of the protons, the alteration of cellular permeability, the formation of bonds with the thiol group of the proteins, the generation of reactive species of oxygen, and the hyperoxidation of DNA, RNA and even the cell membrane. To improve the efficiency of NPs, modifications have been made such as coating with other metals, the addition of antibiotics, detergents and surfactants, as well as the acidification of the solution. Consequently, NPs are considered as a promising method for achieving safety in the agricultural and agrifood area. However, it is necessary to investigate the side effects of NPs, when applied in agroecological systems, on the textural, nutriment and sensory properties of food, as well as the impact on human health. © 2022 Society of Chemical Industry.

Green Synthesized Silver Nanoparticles: A Novel Approach for the Enhanced Growth and Yield of Tomato against Early Blight Disease

Tomato plants are among the most widely cultivated and economically important crops worldwide. Farmers' major challenge when growing tomatoes is early blight disease caused by Alternaria solani, which results in significant yield losses. Silver nanoparticles (AgNPs) have gained popularity recently due to their potential antifungal activity. The present study investigated the potential of green synthesized silver nanoparticles (AgNPs) for enhancing the growth and yield of tomato plants and their resistance against early blight disease. AgNPs were synthesized using leaf extract of the neem tree. Tomato plants treated with AgNPs showed a significant increase in plant height (30%), number of leaves, fresh weight (45%), and dry weight (40%) compared to the control plants. Moreover, the AgNP-treated plants exhibited a significant reduction in disease severity index (DSI) (73%) and disease incidence (DI) (69%) compared to the control plants. Tomato plants treated with 5 and 10 ppm AgNPs reached their maximum levels of photosynthetic pigments and increased the accumulation of certain secondary metabolites compared to the control group. AgNP treatment improved stress tolerance in tomato plants as indicated by higher activities of antioxidant enzymes such as PO (60%), PPO (65%), PAL (65.5%), SOD (65.3%), CAT (53.8%), and APX (73%). These results suggest that using green synthesized AgNPs is a promising approach for enhancing the growth and yield of tomato plants and protecting them against early blight disease. Overall, the findings demonstrate the potential of nanotechnology-based solutions for sustainable agriculture and food security.

Fighting Phytopathogens with Engineered Inorganic-Based Nanoparticles

The development of effective and ecofriendly agrochemicals, including bactericides, fungicides, insecticides, and nematicides, to control pests and prevent plant diseases remains a key challenge. Nanotechnology has provided opportunities for the use of nanomaterials as components in the development of anti-phytopathogenic agents. Indeed, inorganic-based nanoparticles (INPs) are among the promising ones. They may play an effective role in targeting and killing microbes via diverse mechanisms, such as deposition on the microbe surface, destabilization of cell walls and membranes by released metal ions, and the induction of a toxic mechanism mediated by the production of reactive oxygen species. Considering the lack of new agrochemicals with novel mechanisms of action, it is of particular interest to determine and precisely depict which types of INPs are able to induce antimicrobial activity with no phytotoxicity effects, and which microbe species are affected. Therefore, this review aims to provide an update on the latest advances in research focusing on the study of several types of engineered INPs, that are well characterized (size, shape, composition, and surface features) and show promising reactivity against assorted species (bacteria, fungus, virus). Since effective strategies for plant protection and plant disease management are urgently needed, INPs can be an excellent alternative to chemical agrochemical agents as indicated by the present studies.

Sedeveria pink ruby Extract-Mediated Synthesis of Gold and Silver Nanoparticles and Their Bioactivity against Livestock Pathogens and in Different Cell Lines

Biological synthesis of metal nanoparticles has a significant impact in developing sustainable technologies for human, animal, and environmental safety. In this study, we synthesized gold and silver nanoparticles (NPs) using Sedeveria pink ruby (SP) extract and characterized them using UV–visible spectrophotometry, FESEM-EDX, HR-TEM, XRD, and FT-IR spectroscopy. Furthermore, antimicrobial and antioxidant activities and cytotoxicity of the synthesized NPs were evaluated. UV–visible absorption spectra showed λmax at 531 and 410 nm, corresponding to the presence of SP gold NPs (SP-AuNPs) and SP silver NPs (SP-AgNPs). Most NPs were spherical and a few were triangular rods, measuring 5–30 and 10–40 nm, respectively. EDX elemental composition analysis revealed that SP-AuNPs and SP-AgNPs accounted for >60% and 30% of NPs, respectively. Additionally, some organic moieties were present, likely derived from various metabolites in the natural plant extract, which acted as stabilizing and reducing agents. Next, the antimicrobial activity of the NPs against pathogenic microbes was tested. SP-AgNPs showed potent antibacterial activity against Escherichia coli and Yersinia pseudotuberculosis. Moreover, at moderate and low concentrations, both NPs exhibited weak cytotoxicity in chicken fibroblasts (DF-1) and macrophages (HD11) as well as human intestinal cancer cells (HT-29). Meanwhile, at high concentrations, the NPs exhibited strong cytotoxicity in both chicken and human cell lines. Therefore, the synthesized SP-AuNPs and SP-AgNPs may act as promising materials to treat poultry diseases.

Nano-biofertilizers as bio-emerging strategies for sustainable agriculture development: Potentiality and their limitations

Nanotechnology is a burgeoning revolutionary technology in the 21st century. Climate emergencies caused by natural or anthropogenic activities have tragically consequential repercussions on agricultural output worldwide. Modern cropping systems profoundly rely on synthetic fertilizers to deliver necessary nutrients, yet their prolonged and persistent administration is hazardous to the environment, soil fertility, and nutritional dynamics of the rhizospheric microbiome. By addressing the drawback of physico-chemically synthesized nano-dimensioned fertilizer, this review emphasizes on integrating nanoparticles and biofertilizers conjointly as nano-biofertilizers (NBF) which can safeguard global food security, in light of the population surge. Inoculation with nanoparticles and biofertilizers strengthens plant growth and stress tolerance. However, combined together (NBF), they have emerged as a more economically and environmentally sustainable, highly versatile, and long-lasting agriculture tool. Microbe-based green synthesis using the encapsulation of inorganic nanoparticles of Si, Zn, Cu, Fe, Ni, Ti, and Ag as well as organic materials, including chitosan, cellulose, and starch, to formulate NBFs can eliminate the constraints of conventional fertilizer contamination. The application of NBFs is in its infancy in agriculture, yet it has promising potential for transforming traditional farming techniques into smart agriculture, compared to any of the existing strategies. From this perspective, this review is an attempt to provide a comprehensive understanding of the formulations, fabrication, and characterization of NBFs while unraveling the underlying mechanisms of plant-NBF interactions along with their contribution to climate change-induced biotic and abiotic stress tolerance. We substantially summarize the latest advancements of field applications of NBFs for precision farming. Moreover, we critically revised their applications in agro-ecosystems according to the current literature, while also discussing the bottlenecks and future trends for developing potent NBFs.

Antifungal Activity of Selenium Nanoparticles Obtained by Plant-Mediated Synthesis

The continuous need to satisfy world food demand has led to the search for new alternatives to combat economic losses in agriculture caused by phytopathogenic fungi. These organisms cause plant diseases, reducing their productivity and decreasing fruit quality. Among the new tools being explored is nanotechnology. Nanoparticles with antimicrobial properties could be an excellent alternative to address this problem. In this work, selenium nanoparticles (SeNPs) were obtained using plant extracts of Amphipterygium glaucum leaves (SeNPs-AGL) and Calendula officinalis flowers (SeNPs-COF). Characterization of the SeNPs was performed and their ability as antifungal agents against two commercially relevant plant pathogenic fungi, Fusarium oxysporum and Colletotrichum gloeosporioides, was evaluated. Assays were performed with different concentrations of SeNPs (0, 0.25, 0.5, 1.0, and 1.7 mg/mL). It was observed that both SeNPs had antifungal activity against both plant pathogens at concentrations of 0.25 mg/mL and above. SeNPs-AGL demonstrated better antifungal activity and smaller size (around 8.0 nm) than SeNPs-COF (134.0 nm). FTIR analysis evidenced the existence of different functional groups that constitute both types of SeNPs. There are factors that have to be considered in the antimicrobial activity of SeNPs such as nanoparticle size and phytochemical composition of the plant extracts used, as these may affect their bioavailability.

Anti-diabetic efficacy and selective inhibition of methyl glyoxal, intervention with biogenic Zinc oxide nanoparticle

Non-enzymatic glycation of biomolecules results in advanced glycation end products (AGEs), which are responsible for secondary complications in diabetes. Inhibiting methyl glyoxal (MGO) induced advanced glycation end product (AGE) formation is the only way to alleviate diabetic complications. This study aimed to look into the abilities of herbal extract Kigelia africana and K. africana synthesized zinc oxide nanoparticles (ZnONPs) to inhibit the emergence of MG-derived AGEs. The study intended to determine antioxidant and AGE inhibition of the plant extract and ZnONPs. ZnONPs were tested for the efficiency of anti-diabetic activity in streptozotocin-induced diabetic Wister rats. We discovered that the MGO-trapping effects on the prevention of AGE production were mediated by the downregulation of the amplification of MGO-trapping impacts on the hypoglycemic and antihyperlipidemic mechanisms of ZnONPs. According to histological findings, the treatment with ZnONPs also successfully lowers inflammation in the hepatic and renal tissues. Overall, future mechanistic research could establish ZnONPs potential anti-diabetic properties.

New perception about the use of nanofungicides in sustainable agriculture practices

Protecting plants from pathogens using synthetic nanofungicides is not very effective, because it is harmful to the environment. However, it is synthetic fungicides that farmers are familiar with and commonly use. In this modern era, nanotechnology offers a smart solution to environmental issues at the nanoscale level. It is an emergent field and nanoparticles can be synthesized through various methods. Nanofungicides are efficient due to their solubility and permeability, low dose-dependent toxicity, low dose, enhanced bioavailability, targeted delivery, enhanced bioavailability, and controlled release. There are many metallic compounds, such as Cu, Zn, Ag, and TiO₂ available which are used as nanofungicides. There is a contrary relationship between the size of the nanoparticles and their efficacy and antifungal potential. This review article offers a wide knowledge about formulation of nanomaterials as nanofungicides and their role in disease management in plants.

Synthesis of Green Engineered Silver Nanoparticles through Urtica dioica: An Inhibition of Microbes and Alleviation of Cellular and Organismal Toxicity in Drosophila melanogaster

Plant fractions have a diversity of biomolecules that can be used to make complicated reactions for the bioactive fabrication of metal nanoparticles (NPs), in addition to being beneficial as antioxidant medications or dietary supplements. The current study shows that Urtica dioica (UD) and biologically synthesized silver nanoparticles (AgNPs) of UD have antibacterial and antioxidant properties against bacteria (Escherichia coli and Pseudomonas putida) and Drosophila melanogaster (Oregon R+). According to their ability to scavenge free radicals, DPPH, ABTS, TFC, and TPC initially estimated the antioxidant potential of UD and UD AgNPs. The fabricated AgNPs were analyzed (UV−Vis, FTIR, EDS, and SEM) to determine the functional groups (alcohol, carboxylic acids, phenol, proteins, and aldehydes) and to observe the shape (agglomerated crystalline and rod-shaped structure). The disc diffusion method was used to test the antimicrobial properties of synthesized Ag-NPs against E. coli and P. putida. For 24 to 120 h, newly enclosed flies and third instar larvae of Drosophila were treated with UD and UD AgNPs. After exposure, tests for biochemical effects (acetylcholinesterase inhibition and protein estimation assays), cytotoxicity (dye exclusion), and behavioral effects (jumping and climbing assays) were conducted. The results showed that nanoparticles were found to have potent antimicrobial activity against all microbial strains tested at various concentrations. In this regard, ethno-medicinal characteristics exhibit a similar impact in D. melanogaster, showing (p < 0.05) significantly decreased cellular toxicity (trypan blue dye), enhanced biochemical markers (AChE efficacy and proteotoxicity), and improved behavioral patterns in the organism treated with UD AgNPs, especially in comparison to UD extract. The results of this study may help in the utilization of specific plants as reliable sources of natural antioxidants that may have been beneficial in the synthesis of metallic NPs, which aids in the production of nanomedicine and other therapeutic applications.

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.

Methods for Green Synthesis of Metallic Nanoparticles Using Plant Extracts and their Biological Applications - A Review

Nanotechnology, a fast-developing branch of science, is gaining extensive popularity among researchers simply because of the multitude of applications it can offer. In recent years, biological synthesis has been widely used instead of physical and chemical synthesis methods, which often produce toxic products. These synthesis methods are now being commonly adapted to discover new applications of nanoparticles synthesized using plant extracts. In this review, we elucidate the various ways by which nanoparticles can be biologically synthesized. We further discuss the applications of these nanoparticles.

The Role of Selenium Nanoparticles in Agriculture and Food Technology

Selenium (Se) is an essential micronutrient for diverse organisms such as mammals, bacteria, some insects and nematodes, archaea, and algae, as it is involved in a large number of physiological and metabolic processes and is part of approximately 25 selenoproteins in mammals. In plants, Se has no essential metabolic role, high concentrations of inorganic Se can lead to the formation of Se-amino acids, and its incorporation into selenoproteins can generate toxicity. Conversely, low doses of Se can trigger a variety of beneficial effects as an antioxidant, antimicrobial, or stress-modulating agent without being an essential element. Therefore, Se can generate toxicity depending on the dose and the chemical form in which it is supplied. Selenium nanoparticles (SeNPs) have emerged as an approach to reduce this negative effect and improve its biological properties. In turn, SeNPs have a wide range of potential advantages, making them an alternative for areas such as agriculture and food technology. This review focuses on the use of SeNPs and their different applications as antimicrobial agents, growth promoters, crop biofortification, and nutraceuticals in agriculture. In addition, the utilization of SeNPs in the generation of packaging with antioxidant and antimicrobial traits and Se enrichment of animal source foods for human consumption as part of food technology is addressed. Additionally, possible action mechanisms and potential adverse effects are discussed. The concentration, size, and synthesis method of SeNPs are determining factors of their biological properties.

The Symbiotic Fungus Leucoagaricus gongylophorus (Möller) Singer (Agaricales, Agaricaceae) as a Target Organism to Control Leaf-Cutting Ants

Simple Summary

The most used approach to control leaf-cutting ants (which cause damage in agricultural areas) is the application of synthetic chemical compounds that directly affect these insects. But another approach is the use of natural substances that attack the symbiotic fungus responsible for many aspects of the survival of the nest. In this study, we discuss the natural substances already reported in the literature to have fungicidal activity and how they could be applicable as products for the control of leaf-cutting ants.

Abstract

Atta and Acromyrmex are the main genera of leaf-cutting ants present in North and South America, causing extensive damage to agroforestry. Control of the ants requires high handling costs with few effective methods available to decrease the losses. The symbiosis between the leaf-cutting ants and the fungus Leucoagaricus gongylophorus is essential for ant nest survival. Therefore, L. gongylophorus may be a key target in controlling leaf-cutting ants, since its reduction may cause an imbalance in the symbiosis necessary to maintain the nest. Among the options for natural fungal control, plant species are considered important sources of compounds belonging to several classes of natural products that show potential as antifungal agents. This review also presents studies that establish that the antagonist fungi from the Escovopsis and Trichoderma genera effectively reduce the development of L. gongylophorus. The development of nanostructured delivery systems, which have shown advantages over conventional formulations, is suggested for ant control; no commercial nanotechnology-based product has yet been developed, and this appears to be a new approach for future studies.

Green Synthesis of Gold and Silver Nanoparticles Using Leaf Extract of Capsicum chinense Plant

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

Engineered Nanomaterials in Soil: Their Impact on Soil Microbiome and Plant Health

A staggering number of nanomaterials-based products are being engineered and produced commercially. Many of these engineered nanomaterials (ENMs) are finally disposed into the soil through various routes in enormous quantities. Nanomaterials are also being specially tailored for their use in agriculture as nano-fertilizers, nano-pesticides, and nano-based biosensors, which is leading to their accumulation in the soil. The presence of ENMs considerably affects the soil microbiome, including the abundance and diversity of microbes. In addition, they also influence crucial microbial processes, such as nitrogen fixation, mineralization, and plant growth promoting activities. ENMs conduct in soil is typically dependent on various properties of ENMs and soil. Among nanoparticles, silver and zinc oxide have been extensively prepared and studied owing to their excellent industrial properties and well-known antimicrobial activities. Therefore, at this stage, it is imperative to understand how these ENMs influence the soil microbiome and related processes. These investigations will provide necessary information to regulate the applications of ENMs for sustainable agriculture and may help in increasing agrarian production. Therefore, this review discusses several such issues.

Nano-Enabled Products: Challenges and Opportunities for Sustainable Agriculture

Nanotechnology has gained popularity in recent years owing to its established potential for application and implementation in various sectors such as medical drugs, medicine, catalysis, energy, material, and plant science. Nanoparticles (NPs) are smaller in size (1-100 nm) with a larger surface area and have many fruitful applications. The extraordinary functions of NPs are utilized in sustainable agriculture due to nano-enabled products, e.g., nano-insecticides, nano-pesticides, and nano-fertilizers. Nanoparticles have lately been suggested as an alternate method for controlling plant pests such as insects, fungi, and weeds. Several NPs exhibit antimicrobial properties considered in food packaging processes; for example, Ag-NPs are commonly used for such purposes. Apart from their antimicrobial properties, NPs such as Si, Ag, Fe, Cu, Al, Zn, ZnO, TiO2, CeO2, Al2O3, and carbon nanotubes have also been demonstrated to have negative impacts on plant growth and development. This review examines the field-use of nano-enabled products in sustainable agriculture, future perspectives, and growing environmental concerns. The remarkable information on commercialized nano-enabled products used in the agriculture and allied sectors are also provided.

Antibacterial Activity of Biosynthesized Selenium Nanoparticles Using Extracts of Calendula officinalis against Potentially Clinical Bacterial Strains

The use of selenium nanoparticles (SeNPs) in the biomedical area has been increasing as an alternative to the growing bacterial resistance to antibiotics. In this research, SeNPs were synthesized by green synthesis using ascorbic acid (AsAc) as a reducing agent and methanolic extract of Calendula officinalis L. flowers as a stabilizer. Characterization of SeNPs was performed by UV-vis spectrophotometry, infrared spectrophotometry (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM) techniques. SeNPs of 40–60 nm and spherical morphologies were obtained. The antibacterial activity of marigold extracts and fractions was evaluated by disk diffusion methodology. The evaluation of SeNPs at different incubation times was performed through the colony-forming unit (CFU) count, in both cases against Serratia marcescens, Enterobacter cloacae, and Alcaligenes faecalis bacteria. Partial antibacterial activity was observed with methanolic extracts of marigold leaves and flowers and total inhibition with SeNPs from 2 h for S. marcescens, 1 h for E. cloacae, and 30 min for A. faecalis. In addition, SeNPs were found to exhibit antioxidant activity. The results indicate that SeNPs present a potentiated effect of both antimicrobial and antioxidant activity compared to the individual use of marigold extracts or sodium selenite (Na₂SeO₃). Their application emerges as an alternative for the control of clinical pathogens.

Bioinspired Nanomodification Strategies: Moving from Chemical-Based Agrosystems to Sustainable Agriculture

Agrochemicals have supported the development of the agricultural economy and national population over the past century. However, excessive applications of agrochemicals pose threats to the environment and human health. In the last decades, nanoparticles (NPs) have been a hot topic in many fields, especially in agriculture, because of their physicochemical properties. Nevertheless, the prevalent methods for fabricating NPs are uneconomical and involve toxic reagents, hindering their extensive applications in the agricultural sector. In contrast, inspired by biological exemplifications from microbes and plants, their extract and biomass can act as a reducing and capping agent to form NPs without any toxic reagents. NPs synthesized through these bioinspired routes are cost-effective, ecofriendly, and high performing. With the development of nanotechnology, biosynthetic NPs (bioNPs) have been proven to be a substitute strategy for agrochemicals and traditional NPs in heavy-metal remediation of soil, promotion of plant growth, and management of plant disease with less toxicity and higher performance. Therefore, bioinspired synthesis of NPs will be an inevitable trend for sustainable development in agricultural fields. This critical review will demonstrate the bioinspired synthesis of NPs and discuss the influence of bioNPs on agricultural soil, crop growth, and crop diseases compared to chemical NPs or agrochemicals.

Au@Ag Core@Shell Nanoparticles Synthesized with Rumex hymenosepalus as Antimicrobial Agent

In this work, we used a sequential method of synthesis for gold-silver bimetallic nanoparticles with core@shell structure (Au@AgNPs). Rumex hymenosepalus root extract (Rh), which presents high content in catechins and stilbenes, was used as reductor agent in nanoparticles synthesis. Size distribution obtained by Transmission Electron Microscopy (TEM) gives a mean diameter of 36 ± 11 nm for Au@AgNPs, 24 ± 4 nm for gold nanoparticles (AuNPs), and 13 ± 3 nm for silver nanoparticles (AgNPs). The geometrical shapes of NPs were principally quasi-spherical. The thickness of the silver shell over AuNPs is around 6 nm and covered by active biomolecules onto the surface. Nanoparticles characterization included high angle annular dark field images (HAADF) recorded with a scanning transmission electron microscope (STEM), Energy-Dispersive X-ray Spectroscopy (EDS), X-Ray Diffraction (XRD), UV-Vis Spectroscopy, Zeta Potential, and Dynamic Light Scattering (DLS). Fourier Transform Infrared Spectrometer (FTIR), and X-ray Photoelectron Spectroscopy (XPS) show that nanoparticles are stabilized by extract molecules. A growth kinetics study was performed using the Gompertz model for microorganisms exposed to nanomaterials. The results indicate that AgNPs and Au@AgNPs affect the lag phase and growth rate of Escherichia coli and Candida albicans in a dose-dependent manner, with a better response for Au@AgNPs.

Bactericidal and fungicidal capacity of Ag2O/Ag nanoparticles synthesized with Aloe vera extract

This research aims to provide an alternative eco-friendly way to obtain silver species and assess their bactericidal activity. This study reports the synthesis of Ag₂O nanoparticles and Ag nanoparticles reduced with a green synthesis method, using a low-cost and commercial Aloe vera extract. The crystalline phases of Ag and Ag₂O nanoparticles were analyzed by X-ray diffraction. The oxidation states for both species were determined by X-ray photoelectron spectroscopy. The optical properties of the material were studied through optical absorption, which resulted in well-defined band centered at 545 nm. This result is attributed to the morphology and size of the silver nanoparticles. In addition, antibacterial tests were performed on AgNPs biosynthesized with A. vera with the Kirby-Bauer protocol on Gram-negative and Gram-positive bacteria Escherichia coli and Staphylococcus aureaus, respectively. Moreover, antifungal tests were performed with various species from Candida.

Exploitation of Antimicrobial Nanoparticles and Their Applications in Biomedical Engineering

Antibiotic resistance is a major threat to public health, which contributes largely to increased mortality rates and costs in hospitals. The severity and widespread nature of antibiotic resistance result in limited treatments to effectively combat antibiotic-resistant pathogens. Nanoparticles have different or enhanced properties in contrast to their bulk material, including antimicrobial efficacy towards a broad range of microorganisms. Their beneficial properties can be utilised in various bioengineering technologies. Thus, antimicrobial nanoparticles may provide an alternative to challenge antibiotic resistance. Currently, nanoparticles have been incorporated into materials, such as fibres, glass and paints. However, more research is required to elucidate the mechanisms of action fully and to advance biomedical applications further. This paper reviews the antimicrobial efficacies and the intrinsic properties of different metallic nanoparticles, their potential mechanisms of action against certain types of harmful pathogens and how these properties may be utilised in biomedical and healthcare products with the aim to reduce cross contaminations, disease transmissions and usage of antibiotics.