Fungi-assisted silver nanoparticle synthesis and their applications

Pongamia pinnata seed extract-mediated green synthesis of silver nanoparticle loaded nanogel for estimation of their antipsoriatic properties

This research describes the eco-friendly green synthesis of silver nanoparticles employing Pongamia pinnata seed extracts loaded with nanogel formulations (AgNPs CUD NG) to improve the retention, accumulation, and the penetration of AgNPs into the epidermal layer of psoriasis. AgNPs were synthesized using the Box-Behnken design. Optimized AgNPs and AgNPs CUD NG were physico-chemically evaluated using UV-vis spectroscopy, SEM, FT-IR, PXRD, viscosity, spreadability, and retention studies. It was also functionally assessed using an imiquimod-induced rat model. The entrapment efficiency of AgNPs revealed ~ 79.35%. Physico-chemical parameters announced the formation of AgNPs via surface plasmon resonance and interaction between O-H, C = O, and amide I carbonyl group of protein extract and AgNO3. Optimized AgNPs showed spherical NPs ~ 116 nm with better physical stability and suitability for transdermal applications. AgNPs CUD NG revealed non-Newtonian, higher spreadability, and better extrudability, indicating its suitability for a transdermal route. AgNPs CUD NG enhanced the retention of AgNPs on the psoriatic skin compared to normal skin. Optimized formulations exhibit no irritation by the end of 72 h, indicating formulation safety. AgNPs CUD NG at a dose of 1 FTU showed significant recovery from psoriasis with a PASI score of ~ 0.8 compared to NG base and marketed formulations. Results indicated that seed extract-assisted AgNPs in association with CUD-based NG formulations could be a promising nanocarrier for psoriasis and other skin disorders.

Progress in the Sustainable Development of Biobased (Nano)materials for Application in Water Treatment Technologies

Water pollution remains a widespread problem, affecting the health and wellbeing of people around the globe. While current advancements in wastewater treatment and desalination show promise, there are still challenges that need to be overcome to make these technologies commercially viable. Nanotechnology plays a pivotal role in water purification and desalination processes today. However, the release of nanoparticles (NPs) into the environment without proper safeguards can lead to both physical and chemical toxicity. Moreover, many methods of NP synthesis are expensive and not environmentally sustainable. The utilization of biomass as a source for the production of NPs has the potential to mitigate issues pertaining to cost, sustainability, and pollution. The utilization of biobased nanomaterials (bio-NMs) sourced from biomass has garnered attention in the field of water purification due to their cost-effectiveness, biocompatibility, and biodegradability. Several research studies have been conducted to efficiently produce NPs (both inorganic and organic) from biomass for applications in wastewater treatment. Biosynthesized materials such as zinc oxide NPs, phytogenic magnetic NPs, biopolymer-coated metal NPs, cellulose nanocrystals, and silver NPs, among others, have demonstrated efficacy in enhancing the process of water purification. The utilization of environmentally friendly NPs presents a viable option for enhancing the efficiency and sustainability of water pollution eradication. The present review delves into the topic of biomass, its origins, and the methods by which it can be transformed into NPs utilizing an environmentally sustainable approach. The present study will examine the utilization of greener NPs in contemporary wastewater and desalination technologies.

Fungal-mediated synthesis of silver nanoparticles: a novel strategy for plant disease management

Various traditional management techniques are employed to control plant diseases caused by bacteria and fungi. However, due to their drawbacks and adverse environmental effects, there is a shift toward employing more eco-friendly methods that are less harmful to the environment and human health. The main aim of the study was to biosynthesize silver Nanoparticles (AgNPs) from Rhizoctonia solani and Cladosporium cladosporioides using a green approach and to test the antimycotic activity of these biosynthesized AgNPs against a variety of pathogenic fungi. The characterization of samples was done by using UV-visible spectroscopy, SEM (scanning electron microscopy), FTIR (fourier transmission infrared spectroscopy), and XRD (X-ray diffractometry). During the study, the presence of strong plasmon absorbance bands at 420 and 450 nm confirmed the AgNPs biosynthesis by the fungi Rhizoctonia solani and Cladosporium cladosporioides. The biosynthesized AgNPs were 80-100 nm in size, asymmetrical in shape and became spherical to sub-spherical when aggregated. Assessment of the antifungal activity of the silver nanoparticles against various plant pathogenic fungi was carried out by agar well diffusion assay. Different concentration of AgNPs, 5 mg/mL 10 mg/mL and 15 mg/mL were tested to know the inhibitory effect of fungal plant pathogens viz. Aspergillus flavus, Penicillium citrinum, Fusarium oxysporum, Fusarium metavorans, and Aspergillus aflatoxiformans. However, 15 mg/mL concentration of the AgNPs showed excellent inhibitory activity against all tested fungal pathogens. Thus, the obtained results clearly suggest that silver nanoparticles may have important applications in controlling various plant diseases caused by fungi.

Biogenic metallic nanoparticles: from green synthesis to clinical translation

Biogenic metallic nanoparticles (NPs) have garnered significant attention in recent years due to their unique properties and various applications in different fields. NPs, including gold, silver, zinc oxide, copper, titanium, and magnesium oxide NPs, have attracted considerable interest. Green synthesis approaches, utilizing natural products, offer advantages such as sustainability and environmental friendliness. The theranostics applications of these NPs hold immense significance in the fields of medicine and diagnostics. The review explores intricate cellular uptake pathways, internalization dynamics, reactive oxygen species generation, and ensuing inflammatory responses, shedding light on the intricate mechanisms governing their behaviour at a molecular level. Intriguingly, biogenic metallic NPs exhibit a wide array of applications in medicine, including but not limited to anti-inflammatory, anticancer, anti-diabetic, anti-plasmodial, antiviral properties and radical scavenging efficacy. Their potential in personalized medicine stands out, with a focus on tailoring treatments to individual patients based on these NPs' unique attributes and targeted delivery capabilities. The article culminates in emphasizing the role of biogenic metallic NPs in shaping the landscape of personalized medicine. Harnessing their unique properties for tailored therapeutics, diagnostics and targeted interventions, these NPs pave the way for a paradigm shift in healthcare, promising enhanced efficacy and reduced adverse effects.

Potentials of roots, stems, leaves, flowers, fruits, and seeds extract for the synthesis of silver nanoparticles

Silver nanoparticles (AgNPs) have gained significant attention in various applications due to their unique properties that differ from bulk or macro-sized counterparts. In the advancement of nanotechnology, a reliable, non-toxic, and eco-friendly green synthesis has widely been developed as an alternative method for the production of AgNPs, overcoming limitations associated with the traditional physical and chemical methods. Green synthesis of AgNPs involves the utilization of biological sources including plant extracts with silver salt as the precursor. The potential of phytochemicals in plant extracts serves as a reducing/capping and stabilizing agent to aid in the bio-reduction of Ag+ ions into a stable nanoform, Ag0. This review provides insights into the potentials of various plant parts like root, stem, leaf, flower, fruit, and seed extracts that have been extensively reported for the synthesis of AgNPs.

Biogenic silver nanoparticle synthesis using orange peel extract and its multifaceted biomedical application

The aim of this study was to employ an agro-industrial byproduct, specifically Citrus sinensis peels, as a reservoir of polyphenols. The natural chemicals present in C. sinensis peels serve as reducing agents in an environmentally benign method for synthesizing silver nanoparticles (AgNPs). This methodology not only provides a more environmentally friendly method for synthesizing nanoparticles but also enhances the value of agricultural waste, emphasizing the sustainable utilization of resources. In our study, AgNPs were successfully synthesized using peel aqueous exact of C. sinensis and then their various biological activity has been investigated. The synthesized AgNPs were characterized by UV-vis spectroscopy, dynamic light scattering (DLS), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and transmission electron microscopy (TEM) analysis. Furthermore, their effectiveness in inhibiting growth and biofilm formation of Escherichia coli, Staphylococcus aureus, and Candida albicans has been investigated. The minimum inhibitory concentrations (MIC) for E. coli and S. aureus were both 32 μg/mL, and for C. albicans, it was 128 µg/mL. At 250 µg/mL of AgNPs, 94% and 92% biofilm inhibition were observed against E. coli and S. aureus, respectively. Furthermore, AgNPs demonstrated significant toxic effects against human prostate cancer cell line DU145 as investigated by anti-apoptotic, 4',6-diamidino-2-phenylindole (DAPI), reactive oxygen species (ROS), and acridine orange/ethidium bromide (AO/EtBr) assays. We also conducted uptake analysis on these pathogens and cancer cell lines to preliminarily investigate the mechanisms underlying their toxic effects. These findings confirm that AgNPs can serve as a cost-effective, non-toxic, and environmentally friendly resource for green synthesis of medicinal AgNPs. Moreover, this approach offers an alternative recycling strategy that contributes to the sustainable use of biological by-products.

A review on mycogenic metallic nanoparticles and their potential role as antioxidant, antibiofilm and quorum quenching agents

The emergence of antimicrobial resistance among biofilm forming pathogens aimed to search for the efficient and novel alternative strategies. Metallic nanoparticles have drawn a considerable attention because of their significant applications in various fields. Numerous methods are developed for the generation of these nanoparticles however, mycogenic (fungal-mediated) synthesis is attractive due to high yields, easier handling, eco-friendly and being energy efficient when compared with conventional physico-chemical methods. Moreover, mycogenic synthesis provides fungal derived biomolecules that coat the nanoparticles thus improving their stability. The process of mycogenic synthesis can be extracellular or intracellular depending on the fungal genera used and various factors such as temperature, pH, biomass concentration and cultivation time may influence the synthesis process. This review focuses on the synthesis of metallic nanoparticles by using fungal mycelium, mechanism of synthesis, factors affecting the mycosynthesis and also describes their potential applications as antioxidants and antibiofilm agents. Moreover, the utilization of mycogenic nanoparticles as quorum quenching agent in hampering the bacterial cell-cell communication (quorum sensing) has also been discussed.

Entomopathogenic fungi-based silver nanoparticles: a potential substitute of synthetic insecticides to counter behavioral and physiological immunity in Aedes aegypti mosquito (Diptera: Culicidae)

Excessive use of synthetic insecticides has resulted in environmental contamination and adverse effects on humans and other non-target organisms. Entomopathogenic fungi offer eco-friendly alternatives; however, their application for pest control requires significant advancement owing to limitations like slow killing time and effectiveness only when applied in higher amounts, whereas exposure to UV radiation, high temperature, and humidity can also reduce their viability and shelf-life. The nanoparticles synthesized using fungal extracellular extracts provide a new approach to use fungal pathogens. Our study focused on the synthesis of Metarhizium anisopliae-based silver nanoparticles (AgNPs) and evaluation of their efficiency on various physiological and behavioral parameters of the mosquito Aedes aegypti. The synthesis, size (27.6 d.nm, PDI = 0.209), zeta potential (- 24.3 mV), and shape of the AgNPs were determined through dynamic light scattering, scanning and transmission electron microscopic, and UV-visual spectroscopic analyses (432 nm). Our results showed significantly reduced survival (100% decrease in case of 3.2 and 1.8 μL/cm2 volumes, and 60% decrease in case of 0.8 μL/cm2 volume), phenoloxidase activity (t = 39.91; p = 0.0001), and gut microbiota, with increased oxidative stress and cell apoptosis in AgNPs-challenged mosquitoes. Furthermore, the AgNPs-exposed mosquitoes presented a concentration-specific decrease in flight locomotor activity (F = 17.312; p < 0.0001), whereas no significant changes in antifungal activity, self-grooming frequencies, or time spent were found. These findings enhance our understanding of mosquito responses to AgNPs exposure, and offer a more efficient mosquito control strategy using entomopathogenic fungi.

Bio-fabrication of silver nanoparticles using Commelina erecta, L.: a mechanistic approach on synthesis, optimization, antibacterial, and antioxidant potential

The ongoing exploration of economical, sustainable, and environment-friendly methods for synthesizing monodisperse colloidal metal nanoparticles is growing day by day due to their potential application in various fields. The use of plant derivatives in nanoparticle synthesis and their suitability as sustainable catalysts have emerged as significant areas of research. In this study, silver nanoparticles were synthesized using an aqueous extract obtained from the commonly found weed Commelina erecta, L. Extensive study is conducted to optimize various synthesis parameters such as pH, reducing agent concentration, silver nitrate concentration, and temperature. The plant extract utilized in the synthesis process contained variety of antioxidants, including malic acid, phenol, benzoic acid, and catechol, which played a crucial role in both reduction and capping during the synthesis process, thereby making them suitable for biomedical applications. The optimized synthesis process yielded silver nanoparticles with a particle size of 16.2 ± 3.1 nm. These nanoparticles exhibited excellent stability and demonstrated remarkable antibacterial activity compared to the standard antibacterial agent, streptomycin. In addition, the silver nanoparticles displayed promising antioxidant activity attributed to the presence of antioxidant functional groups on their surface. This study reports, for the first time, the synthesis of silver nanoparticles using antioxidant compounds present in C. erecta, L. plant extract. The antioxidant compounds identified through GC-MS belong to phenols, phenolic acids, and carboxylic acid groups. Furthermore, the exceptional antimicrobial and antioxidant properties exhibited by the synthesized silver nanoparticles offer new possibilities for their potential applications.

Phytosynthesis of Silver Nanoparticles Using Oscimum sanctum Leaf Extract and Studies on Its Antidiabetic, Antioxidant, and Antibacterial Properties

The green synthesis of plasmonic metal nanoparticles (NPs) has gained considerable attention among researchers as it is cost-effective, environmentally friendly, energy-saving, and nontoxic. We have synthesized silver NPs (Ag NPs) with Oscimum sanctum (holy Tulsi) medicinal plant leaf extract by green synthesis methods. Further, we investigate the antibacterial, antioxidant, and antidiabetic activities of the synthesized Ag NPs. Oscimum sanctum leaf extract has secondary metabolites such as phenolic and flavonoid compounds, which play a significant role in the synthesis of Ag NPs. Subsequently, these bioactive molecules get adsorbed on the large surfaces of the synthesized NPs. Spectroscopic techniques such as X-ray diffraction (XRD), UV-visible absorption, Fourier-transform infrared, and scanning electron microscopy have been used to study and characterize the phytosynthesized Ag NPs. The XRD pattern confirms the formation of crystalline Ag NPs with a high degree of intensity. UV-visible absorption spectra confirm the surface plasmon resonance peak in the range of 440-450 nm. A scanning electron microscopy picture reveals homogeneous growth of Ag NPs with particle sizes of 200-400 nm; however, crystallite size along different planes has been estimated in the range of 18-23 nm. We have found that these Ag NPs synthesized with Oscimum sanctum leaf extract show inhibitory activity against α-amylase and α-glucosidase enzymes in vitro. Our findings further reveal that these Ag NPs are more effective in inhibiting the growth of Salmonella typhi bacteria as compared to other bacterial strains.

Enhanced Antioxidant Activity and Reduced Cytotoxicity of Silver Nanoparticles Stabilized by Different Humic Materials

The current article describes the biological activity of new biomaterials combining the "green" properties of humic substances (HSs) and silver nanoparticles. The aim is to investigate the antioxidant activity (AOA) of HS matrices (macroligands) and AgNPs stabilized with humic macroligands (HS-AgNPs). The unique chemical feature of HSs makes them very promising ligands (matrices) for AgNP stabilization. HSs have previously been shown to exert many pharmacological effects mediated by their AOA. AgNPs stabilized with HS showed a pronounced ability to bind to reactive oxygen species (ROS) in the test with ABTS. Also, higher AOA was observed for HS-AgNPs as compared to the HS matrices. In vitro cytotoxicity studies have shown that the stabilization of AgNPs with the HS matrices reduces the cytotoxicity of AgNPs. As a result of in vitro experiments with the use of 2,7-dichlorodihydrofluorescein diacetate (DCFDA), it was found that all HS materials tested and the HS-AgNPs did not exhibit prooxidant effects. Moreover, more pronounced AOA was shown for HS-AgNP samples as compared to the original HS matrices. Two putative mechanisms of the pronounced AOA of the tested compositions are proposed: firstly, the pronounced ability of HSs to inactivate ROS and, secondly, the large surface area and surface-to-volume ratio of HS-AgNPs, which facilitate electron transfer and mitigate kinetic barriers to the reduction reaction. As a result, the antioxidant properties of the tested HS-AgNPs might be of particular interest for biomedical applications aimed at inhibiting the growth of bacteria and viruses and the healing of purulent wounds.

Mycosynthesis of silver nanoparticles: a review

Metallic nanoparticles currently show multiple applications in the industrial, clinical and environmental fields due to their particular physicochemical characteristics. Conventional approaches for the synthesis of silver nanoparticles (AgNPs) are based on physicochemical processes which, although they show advantages such as high productivity and good monodispersity of the nanoparticles obtained, have disadvantages such as the high energy cost of the process and the use of harmful radiation or toxic chemical reagents that can generate highly polluting residues. Given the current concern about the environment and the potential cytotoxic effects of AgNPs, once they are released into the environment, a new green chemistry approach to obtain these nanoparticles called biosynthesis has emerged. This new alternative process counteracts some limitations of conventional synthesis methods, using the metabolic capabilities of living beings to manufacture nanomaterials, which have proven to be more biocompatible than their counterparts obtained by traditional methods. Among the organisms used, fungi are outstanding and are therefore being explored as potential nanofactories in an area of research known as mycosynthesis. For all the above, this paper aims to illustrate the advances in state of the art in the mycosynthesis of AgNPs, outlining the two possible mechanisms involved in the process, as well as the AgNPs stabilizing substances produced by fungi, the variables that can affect mycosynthesis at the in vitro level, the applications of AgNPs obtained by mycosynthesis, the patents generated to date in this field, and the limitations encountered by researchers in the area.

The impact of silver nanoparticles on the growth of plants: The agriculture applications

Nanotechnology is the most advanced and rapidly progressing field of science and technology. It primarily deals with developing novelty in nanomaterials by understanding and controlling matter at the nanoscale level. Silver nanoparticles (AgNPs) are the most prominent nanoparticles incorporated with wide-ranging applications, owing to their distinct characteristics. Different methods have been employed for nanoparticles synthesis like chemical method, physical method, photochemical method, top-down/bottom-up approach and biological methods. The positive impacts of silver nanoparticles have been observed in various economy-based sectors, including agriculture. The scientific curiosity about AgNPs in agriculture and plant biotechnology has shown optimum efficacy over the last few years. It not only enhances seed germination and plant growth, but also improves the quantum efficiency of the photosynthetic process. AgNPs play a vital role in agriculture by having several applications that are crucial for ensuring food security and improving crop production. Moreover, they also act as nano-pesticides, providing sufficient dose to the target plants without releasing unnecessary pesticides into the environment. Nano-fertilizers slowly release nutrients to the plants, thereby preventing excessive nutrient loss. AgNPs are utilized for effective and non-toxic pest management, making them an excellent tool for combating pests safely. They combine either edible or non-biodegradable polymers for active food packaging. In addition, AgNPs also possess diverse biological properties such as antiviral, antibacterial and antifungal activities, which protect plants from hazardous microbes. The aim of this review is to comprehensively survey and summarize recent literature regarding the positive and negative impacts of AgNPs on plant growth, as well as their agricultural applications.

The Role of Silver Nanoparticles in Electrochemical Sensors for Aquatic Environmental Analysis

With rapidly increasing environmental pollution, there is an urgent need for the development of fast, low-cost, and effective sensing devices for the detection of various organic and inorganic substances. Silver nanoparticles (AgNPs) are well known for their superior optoelectronic and physicochemical properties, and have, therefore, attracted a great deal of interest in the sensor arena. The introduction of AgNPs onto the surface of two-dimensional (2D) structures, incorporation into conductive polymers, or within three-dimensional (3D) nanohybrid architectures is a common strategy to fabricate novel platforms with improved chemical and physical properties for analyte sensing. In the first section of this review, the main wet chemical reduction approaches for the successful synthesis of functional AgNPs for electrochemical sensing applications are discussed. Then, a brief section on the sensing principles of voltammetric and amperometric sensors is given. The current utilization of silver nanoparticles and silver-based composite nanomaterials for the fabrication of voltammetric and amperometric sensors as novel platforms for the detection of environmental pollutants in water matrices is summarized. Finally, the current challenges and future directions for the nanosilver-based electrochemical sensing of environmental pollutants are outlined.

Mycosynthesis of Metal-Containing Nanoparticles-Synthesis by Ascomycetes and Basidiomycetes and Their Application

Fungi contain species with a plethora of ways of adapting to life in nature. Consequently, they produce large amounts of diverse biomolecules that can be generated on a large scale and in an affordable manner. This makes fungi an attractive alternative for many biotechnological processes. Ascomycetes and basidiomycetes are the most commonly used fungi for synthesis of metal-containing nanoparticles (NPs). The advantages of NPs created by fungi include the use of non-toxic fungus-produced biochemicals, energy efficiency, ambient temperature, pressure conditions, and the ability to control and tune the crystallinity, shape, and size of the NPs. Furthermore, the presence of biomolecules might serve a dual function as agents in NP formation and also capping that can tailor the (bio)activity of subsequent NPs. This review summarizes and reviews the synthesis of different metal, metal oxide, metal sulfide, and other metal-based NPs mediated by reactive media derived from various species. The phyla ascomycetes and basidiomycetes are presented separately. Moreover, the practical application of NP mycosynthesis, particularly in the fields of biomedicine, catalysis, biosensing, mosquito control, and precision agriculture as nanofertilizers and nanopesticides, has been studied so far. Finally, an outlook is provided, and future recommendations are proposed with an emphasis on the areas where mycosynthesized NPs have greater potential than NPs synthesized using physicochemical approaches. A deeper investigation of the mechanisms of NP formation in fungi-based media is needed, as is a focus on the transfer of NP mycosynthesis from the laboratory to large-scale production and application.

Diversity of Biogenic Nanoparticles Obtained by the Fungi-Mediated Synthesis: A Review

Fungi are very promising biological objects for the green synthesis of nanoparticles. Biogenic synthesis of nanoparticles using different mycological cultures and substances obtained from them is a promising, easy and environmentally friendly method. By varying the synthesis conditions, the same culture can be used to produce nanoparticles with different sizes, shapes, stability in colloids and, therefore, different biological activity. Fungi are capable of producing a wide range of biologically active compounds and have a powerful enzymatic system that allows them to form nanoparticles of various chemical elements. This review attempts to summarize and provide a comparative analysis of the currently accumulated data, including, among others, our research group's works, on the variety of the characteristics of the nanoparticles produced by various fungal species, their mycelium, fruiting bodies, extracts and purified fungal metabolites.

Antifungal mechanisms of silver nanoparticles on mycotoxin producing rice false smut fungus

Ustilaginoidea virens, which causes rice false smut disease, is a destructive filamentous fungal pathogen, attracting more attention to search for effective fungicides against U. virens. Here, the results showed that the inhibition of 2 nm AgNPs on U. virens growth and virulence displayed concentration-dependent manner. Abnormalities of fungal morphology were observed upon exposure to AgNPs. RNA-sequencing (RNA-seq) analysis revealed that AgNPs treatment up-regulated 1185 genes and down-regulated 937 genes, which significantly overlapped with the methyltransferase UvKmt6-regulated genes. Furthermore, we found that AgNPs reduced the UvKmt6-mediated H3K27me3 modification, resulting in the up-regulation of ustilaginoidin biosynthetic genes The decrease of H3K27me3 level was associated with the inhibition of mycelial growth by AgNPs treatment. These results suggested that AgNPs are an effective nano-fungicide for the control of rice false smut disease, but when using AgNPs, it needs to be combined with mycotoxin-reducing fungicides to reduce the risk of toxin pollution.

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.

Anti-bacterial effects of functional cosmetics containing silver ions (Ag+ ) on problematic toenails in Republic of Korea

BACKGROUND

Problematic toenails caused by various diseases that are infected by various bacteria are discolored or deformed if left unattended for a long time are gradually increasing in modern society. Accordingly, the present study examines the anti-bacterial effects of LCN products, focused on Pseudomonas aeruginosa and Trichophyton rubrum, which can appear in problematic toenail symptoms. After the treatment, a significant anti-bacterial effect occurring on problematic toenails when a product containing silver ion (Ag⁺ ) will be analyzed.

METHODS

The anti-bacterial activity of LCN functional gel products in anti-fungal and/or anti-bacterial potency was confirmed by the paper disk method against two strains (Pseudomonas aeruginosa and Trichophyton rubum).

RESULTS

From July 2019 to October 2019, 30 men and women in their 20s and 50s who needed to manage problematic toenails in Wonju city, Gangwon-do, Republic of Korea, were asked to use LCN products once every two weeks. After 4 months, changes in the managed toenails were observed. Both products showed very good anti-microbial activity against, Trichophyton rubum but a very weak one against Pseudomonas aeruginosa.

CONCLUSION

As a result of this study, although there was a difference between individuals, the feet treated with LCN products showed effective anti-bacterial activity against topical anti-bacterial effects.

Biosynthesized Gold, Silver, Palladium, Platinum, Copper, and Other Transition Metal Nanoparticles

Nanomedicine is a potential provider of novel therapeutic and diagnostic routes of treatment. Considering the development of multidrug resistance in pathogenic bacteria and the commonness of cancer, novel approaches are being sought for the safe and efficient synthesis of new nanoparticles, which have multifaceted applications in medicine. Unfortunately, the chemical synthesis of nanoparticles raises justified environmental concerns. A significant problem in their widespread use is also the toxicity of compounds that maintain nanoparticle stability, which significantly limits their clinical use. An opportunity for their more extensive application is the utilization of plants, fungi, and bacteria for nanoparticle biosynthesis. Extracts from natural sources can reduce metal ions in nanoparticles and stabilize them with non-toxic extract components.

Recent Advances in Silver Nanoparticles Containing Nanofibers for Chronic Wound Management

Infections are the primary cause of death from burns and diabetic wounds. The clinical difficulty of treating wound infections with conventional antibiotics has progressively increased and reached a critical level, necessitating a paradigm change for enhanced chronic wound care. The most prevalent bacterium linked with these infections is Staphylococcus aureus, and the advent of community-associated methicillin-resistant Staphylococcus aureus has posed a substantial therapeutic challenge. Most existing wound dressings are ineffective and suffer from constraints such as insufficient antibacterial activity, toxicity, failure to supply enough moisture to the wound, and poor mechanical performance. Using ineffective wound dressings might prolong the healing process of a wound. To meet this requirement, nanoscale scaffolds with their desirable qualities, which include the potential to distribute bioactive agents, a large surface area, enhanced mechanical capabilities, the ability to imitate the extracellular matrix (ECM), and high porosity, have attracted considerable interest. The incorporation of nanoparticles into nanofiber scaffolds constitutes a novel approach to “nanoparticle dressing” that has acquired significant popularity for wound healing. Due to their remarkable antibacterial capabilities, silver nanoparticles are attractive materials for wound healing. This review focuses on the therapeutic applications of nanofiber wound dressings containing Ag-NPs and their potential to revolutionize wound healing.

Investigating the anticancer efficacy of biogenic synthesized MgONPs: An in vitro analysis

The biogenic approach of synthesizing metal nanoparticles is an exciting and interesting research area with a wide range of applications. The present study reports a simple, convenient, low-cost method for synthesizing magnesium oxide nanoparticles (MgONPs) from pumpkin seed extracts and their anticancer efficacy against ovarian teratocarcinoma cell line (PA-1). The characteristic features of biogenic MgONPs were assessed by UV–visible spectrophotometry (UV–vis), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The formation of spherical NPs with an average size of 100 nm was observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Moreover, MgONPs exhibit considerable cytotoxicity with an IC₅₀ dose of 12.5 μg/ml. A dose-dependent rise in the induction of apoptosis, ROS formation, and inhibition in the migration of PA-1 cells was observed up to 15 μg/ml concentration, reflecting their significant anticancer potential against ovarian teratocarcinoma cell line. However, additional work, especially in different in vitro and in vivo models, is recommended to find out their real potential before this environment-friendly and cost-effective nanoformulation could be exploited for the benefit of humankind.

Fungi-derived agriculturally important nanoparticles and their application in crop stress management - Prospects and environmental risks

Nanotechnology has a wide range of agricultural applications, with emphasize on the development of novel nano-agrochemicals such as, nano-fertilizer and nano-pesticides. It has a significant impact on sustainable agriculture by increasing agricultural productivity, while reducing the use of inorganic fertilizers, pesticides, and herbicides. Nano-coating delivery methods for agrochemicals have improved agrochemical effectiveness, safety, and consistency. Biosynthesis of nanoparticles (NPs) has recently been recognized as an effective tool, contrary to chemically derived NPs, for plant abiotic and biotic stress control, and crop improvement. In this regard, fungi have tremendous scope and importance for producing biogenic NPs of various sizes, shapes, and characteristics. Fungi are potential candidates for synthesis of biogenic NPs due to their enhanced bioavailability, biological activity, and higher metal tolerance. However, their biomimetic properties and high capacity for dispersion in soil, water environments, and foods may have negative environmental consequences. Furthermore, their bioaccumulation raises significant concerns about the novel properties of nanomaterials potentially causing adverse biological effects, including toxicity. This review provides a concise outline of the growing role of fungal-mediated metal NPs synthesis, its potential applications in crop field, and associated issues of nano-pollution in soil and its future implications.

Biological Synthesis of Silver Nanoparticles by Amaryllis vittata (L.) Herit: From Antimicrobial to Biomedical Applications

The current study sought to synthesize silver nanoparticles (AgNPs) from Amaryllis vittata (L.) leaf and bulb extracts in order to determine their biological significance and use the toxic plants for human health benefits. The formation of silver nanoparticles was detected by a change in color from whitish to brown for bulb-AgNPs and from light green to dark brown for leaf-AgNPs. For the optimization of silver nanoparticles, various experimental physicochemical parameters such as pH, temperature, and salt were determined. UV-vis spectroscopy, Fourier transform infrared spectroscopy, X-ray dispersion spectroscopy, scanning electron microscopy, and energy dispersion spectroscopy analysis were used to characterize nanoparticles. Despite the fact that flavonoids in plant extracts were implicated in the reduction and capping procedure, the prepared nanoparticles demonstrated maximum absorbency between 400 and 500 nm. SEM analysis confirmed the preparation of monodispersed spherical crystalline particles with fcc structure. The bioinspired nanoparticles were found to show effective insecticidal activity against Tribolium castaneum and phytotoxic activity against Lemna aequincotialis. In comparison to plant extracts alone, the tested fabricated nanoparticles showed significant potential to scavenge free radicals and relieve pain. Antibacterial testing against human pathogenic strains, i.e., Escherichia coli and Pseudomonas aureginosa, and antifungal testing against Aspergillus niger revealed the significant potential for microbe resistance using AgNPs. As a result of the findings, the tested silver nanoparticles demonstrated promising potential for developing new and effective pharmacological and agricultural medications. Furthermore, the effects of biogenic AgNPs on an in vitro culture of Solanum tuberosum L. plants were investigated, and the findings indicated that bulb-AgNPs and leaf-AgNPs produced biomass and induced antioxidants via their active constituents. As a result, bulb-AgNPs and leaf-AgNPs may be recommended for use in Solanum tuberosum L. tissue culture for biomass fabrication and metabolic induction.

Recent advances in microbial ε-poly-L-lysine fermentation and its diverse applications

The naturally occurring homo-polyamide biopolymer, ε-poly-L-lysine (ε-PL) consists of 25-35 L-lysine residues with amide linkages between α-carboxyl groups and ε-amino groups. ɛ-PL exhibits several useful properties because of its unusual structure, such as biodegradability, water solubility, no human toxicity, and broad-spectrum antibacterial activities; it is widely applied in the fields of food, medicine, clinical chemistry and electronics. However, current industrial production of ε-PL is only performed in a few countries. Based on an analysis of the physiological characteristics of ε-PL fermentation, current advances that enhance ε-PL fermentation, from strain improvement to product isolation are systematically reviewed, focusing on: (1) elucidating the metabolic pathway and regulatory mechanism of ε-PL synthesis; (2) enhancing biosynthetic performance through mutagenesis, fermentation optimization and metabolic engineering; and (3) understanding and improving the biological activity and functional properties of ε-PL. Finally, perspectives on engineering and exploiting ε-PL as a source material for the production of various advanced materials are also discussed, providing scientific guidelines for researchers to further improve the ε-PL fermentation process.

Green Metallic Nanoparticles: Biosynthesis to Applications

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

Biosustainable production of nanoparticles via mycogenesis for biotechnological applications: A critical review

The demand for the green synthesis of nanoparticles has gained prominence over the conventional chemical and physical syntheses, which often entails toxic chemicals, energy consumption and ultimately lead to negative environmental impact. In the green synthesis approach, naturally available bio-compounds found in plants and fungi can be effective and have been proven to be alternative reducing agents. Fungi or mushrooms are particularly interesting due to their high content of bioactive compounds, which can serve as excellent reducing agents in the synthesis of nanoparticles. Apart from the economic and environmental benefits, such as ease of availability, low synthesis/production cost, safe and no toxicity, the nanoparticles synthesized from this green method have unique physical and chemical properties. Stabilisation of the nanoparticles in an aqueous solution is exceedingly high, even after prolonged storage with unperturbed size uniformity. Biological properties were significantly improved with higher biocompatibility, anti-microbial, anti-oxidant and anti-cancer properties. These remarkable properties allow further exploration in their applications both in the medical and agricultural fields. This review aims to explore the mushroom-mediated biosynthesis of nanomaterials, specifically the mechanism and bio-compounds involved in the synthesis and their interactions for the stabilisation of nanoparticles. Various metal and non-metal nanoparticles have been discussed along with their synthesis techniques and parameters, making them ideal for specific industrial, agricultural, and medical applications. Only recent developments have been explored in this review.

Recent advances on therapeutic potentials of gold and silver nanobiomaterials for human viral diseases

Viral diseases are prominent among the widely spread infections threatening human well-being. Real-life clinical successes of the few available therapeutics are challenged by pathogenic resistance and suboptimal delivery to target sites. Nanotechnology has aided the design of functionalised and non-functionalised Au and Ag nanobiomaterials through physical, chemical and biological (green synthesis) methods with improved antiviral efficacy and delivery. In this review, innovative designs as well as interesting antiviral activities of the nanotechnology-inclined biomaterials of Au and Ag, reported in the last 5 years were critically overviewed against several viral diseases affecting man. These include influenza, respiratory syncytial, adenovirus, severe acute respiratory syndromes (SARS), rotavirus, norovirus, measles, chikungunya, HIV, herpes simplex virus, dengue, polio, enterovirus and rift valley fever virus. Notably identified among the nanotechnologically designed promising antiviral agents include AuNP-M2e peptide vaccine, AgNP of cinnamon bark extract and AgNP of oseltamivir for influenza, PVP coated AgNP for RSV, PVP-AgNPs for SARS-CoV-2, AuNRs of a peptide pregnancy-induce d hypertension and AuNP nanocarriers of antigen for MERS-CoV and SARS-CoV respectively. Others are AgNPs of collagen and Bacillus subtilis for rotavirus, AgNPs labelled Ag30-SiO 2 for murine norovirus in water, AuNPs of Allium sativum and AgNPs of ribavirin for measles, AgNPs of Citrus limetta and Andrographis Paniculata for Chikungunya, AuNPs of efavirenz and stavudine, and AgNPs-curcumin for HIV, NPAuG3-S8 for HSV, AgNPs of Moringa oleifera and Bruguiera cylindrica for dengue while AgNPs of polyethyleneimine and siRNA analogues displayed potency against enterovirus. The highlighted candidates are recommended for further translational studies towards antiviral therapeutic designs.

Optimization of the Synthesis of Fungus-Mediated Bi-Metallic Ag-Cu Nanoparticles

Bi-metallic nanoparticles (NPs) have appeared to be more efficient as antimicrobials than mono-metallic NPs. The fungus Aspergillus terreus-mediated synthesis of bi-metallic Ag-Cu NPs was optimized using response surface methodology (RSM) to reach the maximum yield of NPs. The optimal conditions were validated using ANOVA. The optimal conditions were 1.5 mM total metal (Ag + Cu) concentration, 1.25 mg fungal biomass, 350 W microwave power, and 15 min reaction time. The structure and shape of the synthesized NPs (mostly 20–30 nm) were characterized using several analytical tools. The biological activities of the synthesized NPs were assessed by studying their antioxidant, antibacterial, and cytotoxic activity in different NP concentrations. A dose-dependent response was observed in each test. Bi-metallic Ag-Cu NPs inhibited three clinically relevant human pathogens: Klebsiella pneumoniae, Enterobacter cloacae, and Pseudomonas aeruginosa. Escherichia coli, Enterococcus faecalis, and Staphylococcus aureus were inhibited less. The DPPH and hydrogen peroxide scavenging activities of the NPs were high, reaching 90% scavenging. Ag-Cu NPs could be studied as antimicrobials in different applications. The optimization procedure using statistical analyses was successful in improving the yield of nanoparticles.

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

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

Green Synthesis of Ag Nanoparticles for Plasmon-Assisted Photocatalytic Degradation of Methylene Blue

Green synthesis of metal nanoparticles has been gaining great interest due to the increasing need for eco-friendly manufacturing and application of nanomaterials. Metal nanoparticles, especially silver nanoparticles, are widely used in water treatments and as environmental remedy. Here we present a method to synthesize silver nanoparticles at room temperature using green tea extract under visible light irradiation, along with an application for enhanced photocatalytic degradation on methylene blue (MB) dye. Ag nanoparticles were synthesized under different photoreduction times and then further characterized. The photocatalytic rate of synthesized nanoparticles was also investigated and compared with TiO2 nanowires under UV and visible light irradiations. The results showed that Ag nanoparticles can directly degrade MB dye through plasmonic excitation and electron transferring under visible light, and Ag nanoparticles can further enhance TiO2 photonic degradation by enhanced e-h separation with UV and/or a wide band light, including UV light. Ag nanoparticles under visible light photoreduction for 0.5 h presented better behavior for two kinds of plasmonic enhanced photodegradation; the average size of the nanoparticles is about 30 nm. Therefore, the green synthesized Ag nanoparticles exhibit promising prospects in chemical and biological pollutant treatment.

Metal Nanoparticles as Novel Antifungal Agents for Sustainable Agriculture: Current Advances and Future Directions

The use of metal nanoparticles is considered a good alternative to control phytopathogenic fungi in agriculture. To date, numerous metal nanoparticles (e.g., Ag, Cu, Se, Ni, Mg, and Fe) have been synthesized and used as potential antifungal agents. Therefore, this proposal presents a critical and detailed review of the use of these nanoparticles to control phytopathogenic fungi. Ag nanoparticles have been the most investigated nanoparticles due to their good antifungal activities, followed by Cu nanoparticles. It was also found that other metal nanoparticles have been investigated as antifungal agents, such as Se, Ni, Mg, Pd, and Fe, showing prominent results. Different synthesis methods have been used to produce these nanoparticles with different shapes and sizes, which have shown outstanding antifungal activities. This review shows the success of the use of metal nanoparticles to control phytopathogenic fungi in agriculture.

Assessment of the Antibacterial Potential of Biosynthesized Silver Nanoparticles Combined with Vancomycin Against Methicillin-Resistant Staphylococcus aureus-Induced Infection in Rats

Methicillin-resistant Staphylococcus aureus (MRSA) is considered one of the most serious multidrug-resistant bacteria worldwide. MRSA resistance to methicillin antibiotics made vancomycin, the acceptable treatment option. Silver nanoparticles (Ag-NPs) are among the well-known antibacterial substances showing multimode antibacterial action. Therefore, Ag-NPs are appropriate applicants for use in combination with vancomycin in order to augment its antibacterial action. This study aimed to biosynthesize silver nanoparticles and to evaluate its antibacterial activity against MRSA alone and when combined with vancomycin both in vitro and in vivo. Agaricus bisporus is used to reduce the silver nitrate salts in solution to yield silver nanoparticles which was characterized by UV-visible spectrophotometric analysis that shows maximum absorption at 420 nm as a preliminary confirmation for nanoparticles synthesis, Energy-Dispersive Analysis of X-ray (EDX) which confirms the crystalline nature of silver nanoparticles and transmission electron microscopy (TEM) image shows the particles in spherical form with mean size 27.45 nm. The synthesized silver nanoparticles were tested for antibacterial activity against MRSA, and the synergetic effects of the combination of silver nanoparticles and vancomycin were evaluated. The results showed a strong synergistic antibacterial effect between Ag-NPs and vancomycin in vitro with fractional inhibitory concentration 0.37 and in vivo against MRSA strain. The result revealed that mycosynthesized silver nanoparticles (NPs) enhance the in vitro and in vivo antibacterial activity of vancomycin against MRSA. These results suggested that sliver nanoparticles have an effective antibacterial activity against MRSA count, histopathology, and liver enzymes as well as protective immune response specially when combined with vancomycin in the lungs of infected rats with MRSA.

Advances in Nanotechnology towards Development of Silver Nanoparticle-Based Wound-Healing Agents

Since antiquity, silver-based therapies have been used in wound healing, wound care and management of infections to provide adequate healing. These therapies are associated with certain limitations, such as toxicity, skin discolouration and bacterial resistance, which have limited their use. As a result, new and innovative wound therapies, or strategies to improve the existing therapies, are sought after. Silver nanoparticles (AgNPs) have shown the potential to circumvent the limitations associated with conventional silver-based therapies as described above. AgNPs are effective against a broad spectrum of microorganisms and are less toxic, effective at lower concentrations and produce no skin discolouration. Furthermore, AgNPs can be decorated or coupled with other healing-promoting materials to provide optimum healing. This review details the history and impact of silver-based therapies leading up to AgNPs and AgNP-based nanoformulations in wound healing. It also highlights the properties of AgNPs that aid in wound healing and that make them superior to conventional silver-based wound treatment therapies.

Mycogenic Nano-Complex for Plant Growth Promotion and Bio-Control of Pythium aphanidermatum

(1) Background: biological way is one of the most ecofriendly and safe strategies for nanomaterials synthesis. So, biosynthesis-green method was used for the preparation of Zn(II) complex (in the Nano scale) from the reaction of the schiff base ligand 2,2′-((1E,1′E)-(1,2-phenylenebis (azanylylidene)), bis(methanylylidene))bis(4-bromophenol), and Zn(II)sulphate. The biogenic ZnNP-T was characterized by different methods. Our purpose was to evaluate the ability of biosynthesis-green method for the preparation of Zn(II) complex as an antifungal agent against diseases from fungal species. (2) Methods: in this work, isolates of Pythium aphanidermatum and Trichderma longibrachiatum were obtained, and Trichderma longibrachiatum was used to prepare nano metal complex. We tested the pathogenicity of nano metal complex against seedling and germination of seeds, and we evaluated the effectiveness of ZnNP-T for growth promotion of Vicia feba in early stage and inhibitory activity against Pythium aphanidermatum. (3) Results: antagonistic activity of ZnNP-T was tested in vitro against Pythium aphanidermatum, and then the growth rates of Vicia faba were determined. The obtained data revealed that mycelial growth of pathogenic fungus was inhibited about 73.8% at 20 ppm. In addition, improved the total biomass of Vicia faba in the presence of P. aphanidermatum. All concentration of ZnNP-T positively affected root weight of Vicia faba seedlings, and positively affected shoot weight. Root and shoot lengths were affected by using 20 ppm of ZnNP-T with up to 180 and 96.5 mm of shoot and root length compared to that of the control, while germination percentage was significantly enhanced with up to 100% increase after 72 h of germination. (4) Conclusion: one of the modern challenges in vegetable or fruit production is to enhance seed germination and to grow healthy plants with strong root system. In future, there should be a focus on using of biogenic Zinc nano-complex as plant growth promoter agents.

Synthetic preparations and atomic scale engineering of silver nanoparticles for biomedical applications

Owing to their peculiar oxidative effect, silver cations (Ag⁺) are well known for their antimicrobial properties and explored as therapeutic agents for biomedical applications. Size control with improved dispersion and stability are the key factors of Ag NPs (silver nanoparticles) to be used in biomedical applications. Silver based nano-materials are highly efficient due to their biological, chemical and physical properties in comparison with bulk silver. Atomic scale fabrication is achieved by rearranging the internal components of a material, in turn, influencing the mechanical, electrical, magnetic, thermal and chemical properties. For instance, size and shape have a strong impact on the optical, thermal and catalytic properties of Ag NPs. Such properties can be tuned by controlling the surface/volume ratio of Ag nanostructures with a small size (ideally <100 nm), in turn showing peculiar biological activity different from that of bulk silver. Silver nanomaterials such as nanoparticles, thin films and nanorods can be synthesized by various physical, chemical and biological methods whose most recent implementations will be described in this review. By controlling the structure-functionality relationship, silver based nano-materials have high potential for commercialization in biomedical applications. Antimicrobial, antifungal, antiviral, and anti-inflammatory Ag NPs can be applied in several fields such as pharmaceutics, sensors, coatings, cosmetics, wound healing, bio-labelling agents, antiviral drugs, and packaging.

A Review on Silver Nanoparticles: Classification, Various Methods of Synthesis, and Their Potential Roles in Biomedical Applications and Water Treatment

Recent developments in nanoscience have appreciably modified how diseases are prevented, diagnosed, and treated. Metal nanoparticles, specifically silver nanoparticles (AgNPs), are widely used in bioscience. From time to time, various synthetic methods for the synthesis of AgNPs are reported, i.e., physical, chemical, and photochemical ones. However, among these, most are expensive and not eco-friendly. The physicochemical parameters such as temperature, use of a dispersing agent, surfactant, and others greatly influence the quality and quantity of the synthesized NPs and ultimately affect the material’s properties. Scientists worldwide are trying to synthesize NPs and are devising methods that are easy to apply, eco-friendly, and economical. Among such strategies is the biogenic method, where plants are used as the source of reducing and capping agents. In this review, we intend to debate different strategies of AgNP synthesis. Although, different preparation strategies are in use to synthesize AgNPs such as electron irradiation, optical device ablation, chemical reduction, organic procedures, and photochemical methods. However, biogenic processes are preferably used, as they are environment-friendly and economical. The review covers a comprehensive discussion on the biological activities of AgNPs, such as antimicrobial, anticancer anti-inflammatory, and anti-angiogenic potentials of AgNPs. The use of AgNPs in water treatment and disinfection has also been discussed in detail.

Green-synthesized CeO2 nanoparticles for photocatalytic, antimicrobial, antioxidant and cytotoxicity activities

Cerium oxide nanoparticles (CeO2 NPs) are a sought-after material in numerous fields due to their potential applications such as in catalysis, cancer therapy, photocatalytic degradation of pollutants, sensors, polishing agents. Green synthesis usually involves the production of CeO2 assisted by organic extracts obtained from plants, leaves, flowers, bacteria, algae, food, fruits, etc. The phytochemicals present in the organic extracts adhere to the NPs and act as reducing and/or oxidizing agents and capping agents to stabilize the NPs, modify the particle size, morphology and band gap energy of the as-synthesized materials, which would be advantageous for numerous applications. This review focuses on the green extract-mediated synthesis of CeO2 NPs and discusses the effects on CeO2 NPs of various synthesis methods that have been reported. Several photocatalytic, antimicrobial, antioxidant and cytotoxicity applications have been evaluated, compared and discussed. Future prospects are also suggested.

Green Roccella phycopsis Ach. mediated silver nanoparticles: synthesis, characterization, phenolic content, antioxidant, antibacterial and anti-acetylcholinesterase capacities

In this study, we develop here for the first time an easy, eco-friendly method for synthesizing silver nanoparticles (AgNPs) using the lichen Roccella phycopsis. AgNPs formation was first determined by a color change of the lichen filtrate to brown, subsequent to addition of AgNO₃ solution, and confirmed by a maximum absorbance peak at 425 nm in UV-vis spectrum. Scanning electron microscope images showed a spherical shape with a size distribution between 11 and 18 nm, while the elemental composition was elucidated by the energy dispersive X-ray spectroscopy. The chemical compounds responsible for reduction and stabilization of silver nanoparticles were detected by Frourier transform infrared spectroscopy analysis. The synthesized R. phycopsis silver nanoparticles displayed a strong antioxidant activity. Further, the antibacterial activity was more effective against Gram-negative than Gram-positive bacteria. Besides, the R. phycopsis-AgNPs were potent in inhibiting acetylcholinesterase enzyme with IC₅₀ value of 1.65 ± 0.07 mg/mL.

Polymer Nanocomposites of Selenium Biofabricated Using Fungi

Nanoparticle-reinforced polymer-based materials effectively combine the functional properties of polymers and unique characteristic features of NPs. Biopolymers have attained great attention, with perspective multifunctional and high-performance nanocomposites exhibiting a low environmental impact with unique properties, being abundantly available, renewable, and eco-friendly. Nanocomposites of biopolymers are termed green biocomposites. Different biocomposites are reported with numerous inorganic nanofillers, which include selenium. Selenium is a micronutrient that can potentially be used in the prevention and treatment of diseases and has been extensively studied for its biological activity. SeNPs have attracted increasing attention due to their high bioavailability, low toxicity, and novel therapeutic properties. One of the best routes to take advantage of SeNPs' properties is by mixing these NPs with polymers to obtain nanocomposites with functionalities associated with the NPs together with the main characteristics of the polymer matrix. These nanocomposite materials have markedly improved properties achieved at low SeNP concentrations. Composites based on polysaccharides, including fungal beta-glucans, are bioactive, biocompatible, biodegradable, and have exhibited an innovative potential. Mushrooms meet certain obvious requirements for the green entity applied to the SeNP manufacturing. Fungal-matrixed selenium nanoparticles are a new promising biocomposite material. This review aims to give a summary of what is known by now about the mycosynthesized selenium polymeric nanocomposites with the impact on fungal-assisted manufactured ones, the mechanisms of the involved processes at the chemical reaction level, and problems and challenges posed in this area.

Antibacterial and Antifungal Studies of Biosynthesized Silver Nanoparticles against Plant Parasitic Nematode Meloidogyne incognita, Plant Pathogens Ralstonia solanacearum and Fusarium oxysporum

The possibility of using silver nanoparticles (AgNPs) to enhance the plants growth, crop production, and control of plant diseases is currently being researched. One of the most effective approaches for the production of AgNPs is green synthesis. Herein, we report a green and phytogenic synthesis of AgNPs by using aqueous extract of strawberry waste (solid waste after fruit juice extraction) as a novel bioresource, which is a non-hazardous and inexpensive that can act as a reducing, capping, and stabilizing agent. Successful biosynthesis of AgNPs was monitored by UV-visible spectroscopy showing a surface plasmon resonance (SPR) peak at ~415 nm. The X-ray diffraction studies confirm the face-centered cubic crystalline AgNPs. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques confirm the rectangular shape with an average size of ~55 nm. The antibacterial and antifungal efficacy and inhibitory impact of the biosynthesized AgNPs were tested against nematode, Meloidogyne incognita, plant pathogenic bacterium, Ralstonia solanacearum and fungus, Fusarium oxysporum. These results confirm that biosynthesized AgNPs can significantly control these plant pathogens.

Copper mining bacteria: Converting toxic copper ions into a stable single-atom copper

The chemical synthesis of monoatomic metallic copper is unfavorable and requires inert or reductive conditions and the use of toxic reagents. Here, we report the environmental extraction and conversion of CuSO₄ ions into single-atom zero-valent copper (Cu⁰) by a copper-resistant bacterium isolated from a copper mine in Brazil. Furthermore, the biosynthetic mechanism of Cu⁰ production is proposed via proteomics analysis. This microbial conversion is carried out naturally under aerobic conditions eliminating toxic solvents. One of the most advanced commercially available transmission electron microscopy systems on the market (NeoArm) was used to demonstrate the abundant intracellular synthesis of single-atom zero-valent copper by this bacterium. This finding shows that microbes in acid mine drainages can naturally extract metal ions, such as copper, and transform them into a valuable commodity.

Approaches to safe living and diet after solid organ transplantation

SOT recipients are at high risk for developing severe infectious complications following discharge from the hospital. Comprehensive anticipatory guidance surrounding everyday lifestyle choices can potentially prevent exposure to infectious agents from the environment. This paper reviews the risks that pediatric and adolescent SOT recipients encounter through exposures such as household contacts, outdoor activities, travel, animal exposures, and dietary choices. Although strong evidence is lacking, this paper makes recommendations aimed at minimizing the risk of infectious complications and hospitalization in pediatric SOT recipients.