Characterization, antioxidant and antimicrobial activity of silver nanoparticles synthesized using marine endophytic fungus- Cladosporium cladosporioides

Assessing the Potential of Aconitum Laeve Extract for Biogenic Silver and Gold Nanoparticle Synthesis and Their Biological and Catalytic Applications

The adoption of green chemistry protocols in nanoparticle (NP) synthesis has exhibited substantial potential and is presently a central focus in research for generating versatile NPs applicable across a broad spectrum of applications. In this scientific contribution, we, for the first time, examined the ability of Aconitum Laeve (A. Laeve) crude extract to synthesize silver and gold nanoparticles (AgNPs@AL; AuNP@AL) and explored their potential applications in biological activities and the catalytic degradation of environmental pollutants. The synthesized NPs exhibited a distinctive surface plasmon resonance pattern, a spherical morphology with approximate sizes of 5-10 nm (TEM imaging), a crystalline architecture (XRD analysis), and potential functional groups identified by FTIR spectroscopy. The antibacterial activity was demonstrated by inhibition zones that measured 16 and 14 mm for the AgNPs@AL and AuNP@AL at a concentration of 80 µg/mL against Staphylococcus aureus and 14 and 12 mm against Escherichia coli, respectively. The antioxidant potential of the synthesized NPs was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2-Phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-Oxide (PTIO), and 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assays. Our findings suggest that the AuNP@AL effectively countered the tested radicals considerably, displaying IC50 values of 115.9, 103.54, and 180.85 µg/mL against DPPH, PTIO, and ABTS, respectively. In contrast, the AgNPs@AL showed IC50 values of 144.9, 116.36, and 95.39 µg/mL against the respective radicals. In addition, both the NPs presented significant effectiveness in the photocatalytic degradation of methylene blue and rhodamine B. The overall observations indicate that A. Laeve possesses a robust capability to synthesize spherical nanoparticles, exhibiting excellent dispersion and showcasing potential applications in both biological activities and environmental remediation.

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

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

Unveiling the cytotoxic and anti-proliferative potential of green-synthesized silver nanoparticles mediated by Colletotrichum gloeosporioides

Fungal endophytes are a putative source of bioactive metabolites that have found significant applications in nanomedicine due to their metabolic versatility. In the present study, an aqueous extract of the fungal endophyte, Colletotrichum gloeosporioides associated with a medicinal plant Oroxylum indicum, has been used for the fabrication of green silver nanoparticles (CgAgNPs) and further evaluated their cytotoxic and anti-proliferative activity. Bioanalytical techniques including UV-Vis spectral analysis revealed a sharp band at 435 nm and functional molecules from the aqueous extract involved in the synthesis of CgAgNPs were evidenced through FTIR. Further, the crystalline nature of CgAgNPs was determined through XRD analysis and microscopy techniques including AFM, TEM and FESEM demonstrated the spherical shape of CgAgNPs exhibiting a crystalline hexagonal lattice and the size was found to be in the range of 9-29 nm. The significant cytotoxic potential of CgAgNPs was observed against breast cancer cells, MDA-MB-231 and MCF-7 with IC50 values of 18.398 ± 0.376 and 38.587 ± 1.828 μg mL-1, respectively. The biochemical study revealed that the treatment of MDA-MB-231 and MCF-7 cells with CgAgNPs reduces glucose uptake, suppresses cell proliferation, and enhances LDH release, indicating reduced cell viability and progression. Moreover, our research revealed differential expression of genes associated with apoptosis, cell cycle inhibition and metastasis suppression, evidencing anti-proliferative activity of CgAgNPs. The main objective of the present study is to harness anti-breast cancer activity of novel biogenic nanoparticles synthesized using the aqueous extract of O. indicum associated C. gloeosporioides and study the underlying mechanistic pathway exerted by these mycogenic nanoparticles.

Application of Nanomaterials in the Production of Biomolecules in Microalgae: A Review

Nanomaterials (NMs) are becoming more commonly used in microalgal biotechnology to empower the production of algal biomass and valuable metabolites, such as lipids, proteins, and exopolysaccharides. It provides an effective and promising supplement to the existing algal biotechnology. In this review, the potential for NMs to enhance microalgal growth by improving photosynthetic utilization efficiency and removing reactive oxygen species is first summarized. Then, their positive roles in accumulation, bioactivity modification, and extraction of valuable microalgal metabolites are presented. After the application of NMs in microalgae cultivation, the extracted metabolites, particularly exopolysaccharides, contain trace amounts of NM residues, and thus, the impact of these residues on the functional properties of the metabolites is also evaluated. Finally, the methods for removing NM residues from the extracted metabolites are summarized. This review provides insights into the application of nanotechnology for sustainable production of valuable metabolites in microalgae and will contribute useful information for ongoing and future practice.

Fungi-mediated synthesis of nanoparticles: characterization process and agricultural applications

In the field of nanotechnology, the use of biologically active products from fungi for the reduction and synthesis of nanoparticles as an alternative to toxic chemicals has received extensive attention, due to their production of large quantities of proteins, high yields, easy handling, and the low toxicity of the residues. Fungi have become valuable tools for the manufacture of nanoparticles in comparison with other biological systems because of their enhanced growth control and diversity of metabolites, including enzymes, proteins, peptides, polysaccharides, and other macro-molecules. The ability to use different species of fungi and to perform the synthesis under different conditions enables the production of nanoparticles with different physicochemical characteristics. Fungal nanotechnology has been used to develop and offer products and services in the agricultural, medicinal, and industrial sectors. Agriculturally, it has found applications in plant disease management, crop improvement, biosensing, and the production of environmentally friendly, non-toxic pesticides and fertilizers to enhance agricultural production in general. The subject of this review is the application of fungi in the synthesis of inorganic nanoparticles, characterization, and possible applications of fungal nanoparticles in the diverse agricultural sector. The literature shows potential uses of fungi in biogenic synthesis, enabling the production of nanoparticles with different physiognomies. © 2023 Society of Chemical Industry.

Updates on Biogenic Metallic and Metal Oxide Nanoparticles: Therapy, Drug Delivery and Cytotoxicity

The ambition to combat the issues affecting the environment and human health triggers the development of biosynthesis that incorporates the production of natural compounds by living organisms via eco-friendly nano assembly. Biosynthesized nanoparticles (NPs) have various pharmaceutical applications, such as tumoricidal, anti-inflammatory, antimicrobials, antiviral, etc. When combined, bio-nanotechnology and drug delivery give rise to the development of various pharmaceutics with site-specific biomedical applications. In this review, we have attempted to summarize in brief the types of renewable biological systems used for the biosynthesis of metallic and metal oxide NPs and the vital contribution of biogenic NPs as pharmaceutics and drug carriers simultaneously. The biosystem used for nano assembly further affects the morphology, size, shape, and structure of the produced nanomaterial. The toxicity of the biogenic NPs, because of their pharmacokinetic behavior in vitro and in vivo, is also discussed, together with some recent achievements towards enhanced biocompatibility, bioavailability, and reduced side effects. Because of the large biodiversity, the potential biomedical application of metal NPs produced via natural extracts in biogenic nanomedicine is yet to be explored.

Recent Advances and Perspectives of Nanomaterials in Agricultural Management and Associated Environmental Risk: A Review

The advancement in nanotechnology has enabled a significant expansion in agricultural production. Agri-nanotechnology is an emerging discipline where nanotechnological methods provide diverse nanomaterials (NMs) such as nanopesticides, nanoherbicides, nanofertilizers and different nanoforms of agrochemicals for agricultural management. Applications of nanofabricated products can potentially improve the shelf life, stability, bioavailability, safety and environmental sustainability of active ingredients for sustained release. Nanoscale modification of bulk or surface properties bears tremendous potential for effective enhancement of agricultural productivity. As NMs improve the tolerance mechanisms of the plants under stressful conditions, they are considered as effective and promising tools to overcome the constraints in sustainable agricultural production. For their exceptional qualities and usages, nano-enabled products are developed and enforced, along with agriculture, in diverse sectors. The rampant usage of NMs increases their release into the environment. Once incorporated into the environment, NMs may threaten the stability and function of biological systems. Nanotechnology is a newly emerging technology, so the evaluation of the associated environmental risk is pivotal. This review emphasizes the current approach to NMs synthesis, their application in agriculture, interaction with plant-soil microbes and environmental challenges to address future applications in maintaining a sustainable environment.

Antifungal Activity of Juglans-regia-Mediated Silver Nanoparticles (AgNPs) against Aspergillus-ochraceus-Induced Toxicity in In Vitro and In Vivo Settings

Aflatoxins produced by some species of Aspergillus are considered secondary toxic fungal by-products in feeds and food. Over the past few decades, many experts have focused on preventing the production of aflatoxins by Aspergillus ochraceus and also reducing its toxicity. Applications of various nanomaterials in preventing the production of these toxic aflatoxins have received a lot of attention recently. The purpose of this study was to ascertain the protective impact of Juglans-regia-mediated silver nanoparticles (AgNPs) against Aspergillus-ochraceus-induced toxicity by exhibiting strong antifungal activity in in vitro (wheat seeds) and in vivo (Albino rats) settings. For the synthesis of AgNPs, the leaf extract of J. regia enriched with high phenolic (72.68 ± 2.13 mg GAE/g DW) and flavonoid (18.89 ± 0.31 mg QE/g DW) contents was used. Synthesized AgNPs were characterized by various techniques, including TEM, EDX, FT-IR, and XRD, which revealed that the particles were spherical in shape with no agglomeration and fine particle size in the range of 16-20 nm. In vitro antifungal activity of AgNPs was tested on wheat grains by inhibiting the production of toxic aflatoxins by A. ochraceus. According to the results obtained from High-Performance Liquid Chromatography (HPLC) and Thin-Layer Chromatography (TLC) analyses, there was a correlation between the concentration of AgNPs and a decrease in the production of aflatoxin G1, B1, and G2. For in vivo antifungal activity, Albino rats were administrated with different doses of AgNPs in five groups. The results indicated that the feed concentration of 50 µg/kg feed of AgNPs was more effective in improving the disturbed levels of different functional parameters of the liver (alanine transaminase (ALT): 54.0 ± 3.79 U/L and aspartate transaminase (AST): 206 ± 8.69 U/L) and kidney (creatinine 0.49 ± 0.020 U/L and BUN 35.7 ± 1.45 U/L), as well as the lipid profile (LDL 22.3 ± 1.45 U/L and HDL 26.3 ± 2.33 U/L). Furthermore, the histopathological analysis of various organs also revealed that the production of aflatoxins was successfully inhibited by AgNPs. It was concluded that the harmful effects of aflatoxins produced by A. ochraceus can be successfully neutralized by using J. regia-mediated AgNPs.

Phytochemistry and Biological Activities of Endophytic Fungi from the Meliaceae Family

Meliaceae plants are found worldwide in tropical or subtropical climates. They are important ethnobotanically as sources of traditional medicine, with 575 species and 51 genera. Previous research found that microorganisms are plant pioneers to produce secondary metabolites with diverse compound structures and bioactivities. Several plants of the Meliaceae family contain secondary metabolites isolated from endophytic fungi. Furthermore, related articles from 2002 to 2022 were collected from SciFinder, Google Scholar, and PubMed. About 276 compounds were isolated from endophytic fungi such as terpenoids, polyketides, lactones, pyrones, quinone, anthraquinones, xanthones, coumarines, isocoumarines, resorcylic acid lactones, cytochalasins, aromatics, ester, quinols, alkaloids, nitro compound, fatty acids, and sugars with bioactivities such as antioxidant, antibacterial, antifungal, anti-influenza, neuroprotective activities, anti-HIV, cytotoxic, allelopathic, anti-inflammatory, antifeedant effects, and BSLT toxicity. Meanwhile, secondary metabolites isolated from endophytic fungi were reported as one of the sources of active compounds for medicinal chemistry. This comprehensive review summarizes the ethnobotanical uses and secondary metabolites derived from Meliaceae endophytic fungi.

Evaluation of acute toxicity response to the algae Chlorella pyrenoidosa of biosynthetic silver nanoparticles catalysts

Biosynthetic of silver nanoparticles (AgNPs) by using fungi has attracted much attention due to its high catalytic efficiency and environmentally friendly characteristic. However, a few studies have focused on the ecological toxicity effects of biogenic AgNPs on algae. Here, we first investigated the catalytic reduction of 4-nitrophenol (4-NP) by WZ07-AgNPs biosynthesized by Letendraea sp. WZ07. WZ07-AgNPs had significant catalytic activity with 97.08% degradation of 4-NP in 3.5 min. Then, the toxic effects of WZ07-AgNPs and commercial-AgNPs were compared by Chlorella pyrenoidosa growth, chlorophyll content, protein content, physiological, and biochemical indexes. The results demonstrated that the algal cell biomass of C. pyrenoidosa was differentially inhibited after exposure to different concentrations of AgNPs, which showed concentration dependence and time dependence. The 96h-EC₅₀ values of WZ07-AgNPs and commercial-AgNPs on C. pyrenoidosa were 15.99 mg/mL and 12.69 mg/mL, respectively. With the increase concentration of AgNPs, the chlorophyll content was gradually decreased, the protein content was first increased and then decreased, the activities of superoxide dismutase (SOD) and catalase (CAT) were decreased, and the level of malondialdehyde (MDA) was increased significantly of C. pyrenoidosa. In general, AgNPs affect the growth of algae to some extent. However, compared with commercial-AgNPs, WZ07-AgNPs is less toxic to C. pyrenoidosa, which could be used as a potential and an eco-friendly catalyst. This study provides a basis for the safe application of biosynthetic AgNPs.

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.

New Green Approaches in Nanoparticles Synthesis: An Overview

Nanotechnology is constantly expanding, with nanomaterials being more and more used in common commercial products that define our modern life. Among all types of nanomaterials, nanoparticles (NPs) occupy an important place, considering the great amount that is produced nowadays and the diversity of their applications. Conventional techniques applied to synthesize NPs have some issues that impede them from being appreciated as safe for the environment and health. The alternative to these might be the use of living organisms or biological extracts that can be involved in the green approach synthesis of NPs, a process that is free of harmful chemicals, cost-effective and a low energy consumer. Several factors, including biological reducing agent concentration, initial precursor salt concentration, agitation, reaction time, pH, temperature and light, can influence the characteristics of biologically synthesized NPs. The interdependence between these reaction parameters was not explored, being the main impediment in the implementation of the biological method on an industrial scale. Our aim is to present a brief review that focuses on the current knowledge regarding how the aforementioned factors can control the size and shape of green-synthesized NPs. We also provide an overview of the biomolecules that were found to be suitable for NP synthesis. This work is meant to be a support for researchers who intend to develop new green approaches for the synthesis of NPs.

Ganoderma lucidum: Unutilized natural medicine and promising future solution to emerging diseases in Africa

Ganoderma lucidum is a well-known medicinal mushroom that has been used for the prevention and treatment of different ailments to enhance longevity and health specifically in China, Japan, and Korea. It was known as “God’s herb” in ancient China as it was believed to prolong life, enhance the youthful spirit and sustain/preserve vitality. G. lucidum is seldom collected from nature and is substantially cultivated on wood logs and sawdust in plastic bags or bottles to meet the international market demand. Both in vitro and in vivo studies on the copious metabolic activities of G. lucidum have been carried out. Varied groups of chemical compounds including triterpenoids, polysaccharides, proteins, amino acids, nucleosides, alkaloids, steroids, lactones, lectins, fatty acids, and enzymes with potent pharmacological activities have been isolated from the mycelia and fruiting bodies of G. lucidum. Several researchers have reported the abundance and diversification of its biological actions triggered by these chemical compounds. Triterpenoids and polysaccharides of G. lucidum have been reported to possess cytotoxic, hepatoprotective, antihypertensive, hypocholesterolemic, antihistaminic effects, antioxidant, antimicrobial, anti-inflammatory, hypoglycemic antiallergic, neuroprotective, antitumor, immunomodulatory and antiangiogenic activities. Various formulations have been developed, patented, and utilized as nutraceuticals, cosmeceuticals, and pharmaceuticals from G. lucidum extracts and active compounds. Thus, this review presents current updates on emerging infectious diseases and highlights the scope, dynamics, and advances in infectious disease management with a particular focus on Ganoderma lucidum, an unutilized natural medicine as a promising future solution to emerging diseases in Africa. However, details such as the chemical compound and mode of action of each bioactive against different emerging diseases were not discussed in this study.

Mycology-Nanotechnology Interface: Applications in Medicine and Cosmetology

In today's time, nanotechnology is being utilized to develop efficient products in the cosmetic and pharmaceutical industries. The application of nanotechnology in transforming bioactive material into nanoscale products substantially improves their biocompatibility and enhances their effectiveness, even when used in lower quantities. There is a significant global market potential for these nanoparticles because of which research teams around the world are interested in the advancements in nanotechnology. These recent advances have shown that fungi can synthesize metallic nanoparticles via extra- and intracellular mechanisms. Moreover, the chemical and physical properties of novel metallic nanoparticles synthesised by fungi are improved by regulating the surface chemistry, size, and surface morphology of the nanoparticles. Compared to chemical synthesis, the green synthesis of nanoparticles offers a safe and sustainable approach for developing nanoparticles. Biosynthesised nanoparticles can potentially enhance the bioactivities of different cellular fractions, such as plant extracts, fungal extracts, and metabolites. The nanoparticles synthesised by fungi offer a wide range of applications. Recently, the biosynthesis of nanoparticles using fungi has become popular, and various ways are being explored to maximize nanoparticles synthesis. This manuscript reviews the characteristics and applications of the nanoparticles synthesised using the different taxa of fungi. The key focus is given to the applications of these nanoparticles in medicine and cosmetology.

Biogenic synthesis of silver nanoparticles mediated by the consortium comprising the marine fungal filtrates of Penicillium oxalicum and Fusarium hainanense along with their antimicrobial, antioxidant, larvicidal and anticancer potency

AIM

To biosynthesize silver nanoparticles (AgNPs) using fungal isolates [DS-2 (Penicillium oxalicum) and DW-8 (Fusarium hainanense)] as well as their mixed cell free filtrate (CFF) acting as a consortium (DSW-28) and their bio-potentials.

METHODS AND RESULTS

The fungi (DS-2 and DW-8) were harvested and CFF was prepared. CFF of each fungus and their mixture were reacted with silver nitrate solution under dark conditions for the synthesis of AgNPs. The UV-Visible spectra determined the surface plasmon resonance at 438, 441 and 437 nm for the AgNPs synthesized by DS-2, DW-8 and DSW-28, respectively. The band gap energy was found between 2.21 eV to 2.24 eV which depicted their ability to act as a semiconductor. The TEM imaging revealed the spherical shape and small size of AgNPs. The XRD pattern exhibited the crystalline structure corresponding to their peaks. The FTIR spectra indicates the presence of different functional groups present on the surface of AgNPs. The broad-spectrum antimicrobial activity was exhibited by AgNPs. The AgNPs also acts as an effective antioxidant by depicting their radical scavenging activity against DPPH. Moreover, the AgNPs also inhibited the growth of 4^th instar larvae of Aedes aegypti and Culex quinquefasciatus more efficiently in a dose-dependent method. The biosynthesized AgNPs from DSW-28 showed a significant anticancer activity against MCF-7 cells.

CONCLUSION

The silver nanoparticles synthesized by the CFF of two different fungi acts synergistically in a consortium leading towards the production of silver nanoparticles with smaller size and higher bioactivity.

SIGNIFICANCE AND IMPACT OF STUDY

The impressive bioactivity of the silver nanoparticles synthesized by the mixture of CFF of various fungi acting as a consortium recommends their prospective use in agriculture as well as in biomedical as an antimicrobial, antioxidant, larvicidal and anticancer agents in future.

Application of Metal Nanoparticles for Production of Self-Sterilizing Coatings

Metal nanoparticles (NPs) are increasingly being used in many areas, e.g., industry, pharmacy, and biomedical engineering. NPs can be obtained through chemical and biological synthesis or using physical methods. AgNPs, AuNPs, CuNPs, FeNPs, MgNPs, SnO2NPs, TiO2NPs, and ZnONPs are the most commonly synthesized metal nanoparticles. Many of them have anti-microbial properties and documented activity supported by many tests against some species of pathogenic bacteria, viruses, and fungi. AgNPs, which are used for the production of commercial self-sterilizing packages, are one of the best-explored nanoparticles. Moreover, the EFSA has approved the use of small doses of silver nanoparticles (0.05 mg Ag·kg−1) to food products. Recent studies have shown that metal NPs can be used for the production of coatings to prevent the spread of the SARS-CoV-2 virus, which has caused the global pandemic. Some nanoparticles (e.g., ZnONPs and MgONPs) have the Generally Recognized As Safe (GRAS) status, i.e., they are considered safe for consumption and can be used for the production of edible coatings, protecting food against spoilage. Promising results have been obtained in research on the use of more than one type of nanometals, which prevents the development of pathogen resistance through various mechanisms of inactivation thereof.

Endophytic Microorganisms From the Tropics as Biofactories for the Synthesis of Metal-Based Nanoparticles: Healthcare Applications

Nanoparticles (NPs) have gained great attention in recent years due to their extensive and innovative applications in the field of medicine. However, conventional physicochemical approaches for the synthesis of NPs may be limited and costly, and the reaction by-products are potentially toxic for human health and the environment. Bio-mediated synthesis of NPs exploiting microorganisms as nanofactories has emerged as an alternative to traditional methods, as it provides economic and environmental benefits. Tropical ecosystems harbor a high diversity of endophytes, which have a diverse array of metabolic pathways that confer habitat adaptation and survival and that can be used to produce novel bioactive compounds with a variety of biological properties. Endophytic bacteria and fungi cultivated under optimum conditions have potential for use in biogenic synthesis of NPs with different characteristics and desired activities for medical applications, such as antimicrobial, antitumoral, antioxidant and anti-inflammatory properties. The bio-mediated synthesis of metal-based NPs can be favored because endophytic microorganisms may tolerate and/or adsorb metals and produce enzymes used as reducing agents. To our knowledge, this is the first review that brings together exclusively current research highlighting on the potential of endophytic bacteria and fungi isolated from native plants or adapted to tropical ecosystems and tropical macroalgae as nanofactories for the synthesis of NPs of silver, gold, copper, iron, zinc and other most studied metals, in addition to showing their potential use in human health.

Physicochemical properties, anticancer and antimicrobial activities of metallic nanoparticles green synthesized by Aspergillus kambarensis

In the present study, metal and metal oxide nanoparticles were successfully synthesized using Aspergillus kambarensis. UV-Vis spectroscopy showed maximum absorbance of 417 nm for silver (AgNPs), 542 nm for gold (AuNPs), 582 nm for copper (CuNPs) and 367 nm for zinc oxide (ZnONPs) nanoparticles. Fourier transform infrared spectroscopy indicated the presence of various mycochemicals with diverse functional groups in the fungal cell-free filtrate. Transmission electron microscopy revealed mono and poly dispersed particles with an estimate size of 50 nm and different shapes for synthesized manufacture metallic nanoparticles (MNPs. Dynamic light scattering confirmed that MNPs were dispersed in the size range less than 50 nm. Zeta potential analysis showed values of -41.32 mV (AgNPs), -41.26 mV (AuNPs), -34.74 mV (CuNPs) and 33.72 mV (ZnONPs). X-ray diffraction analysis demonstrated crystalline nature for MNPs. All the synthesized MNPs except AuNPs showed strong antifungal and antibacterial activity in disc diffusion assay with growth inhibition zones of 13.1-44.2 mm as well as anticancer activity against HepG-2 cancer cell line with IC50 in the range of 62.01-77.03 µg/ml. Taken together, the results show that biologically active MNPs synthesized by A. kambarensis for the first time could be considered as promising antimicrobial and anticancer agents for biomedical applications.

Synthesis, Characterization and Biomedical Application of Silver Nanoparticles

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

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

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

Biological Synthesis of Nanocatalysts and Their Applications

Over the past few decades, the synthesis and potential applications of nanocatalysts have received great attention from the scientific community. Many well-established methods are extensively utilized for the synthesis of nanocatalysts. However, most conventional physical and chemical methods have some drawbacks, such as the toxicity of precursor materials, the requirement of high-temperature environments, and the high cost of synthesis, which ultimately hinder their fruitful applications in various fields. Bioinspired synthesis is eco-friendly, cost-effective, and requires a low energy/temperature ambient. Various microorganisms such as bacteria, fungi, and algae are used as nano-factories and can provide a novel method for the synthesis of different types of nanocatalysts. The synthesized nanocatalysts can be further utilized in various applications such as the removal of heavy metals, treatment of industrial effluents, fabrication of materials with unique properties, biomedical, and biosensors. This review focuses on the biogenic synthesis of nanocatalysts from various green sources that have been adopted in the past two decades, and their potential applications in different areas. This review is expected to provide a valuable guideline for the biogenic synthesis of nanocatalysts and their concomitant applications in various fields.

Fungi as veritable tool in current advances in nanobiotechnology

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

Biogenic Silver Nanoparticles: What We Know and What Do We Need to Know?

Nanobiotechnology is considered to be one of the fastest emerging fields. It is still a relatively new and exciting area of research with considerable potential for development. Among the inorganic nanomaterials, biogenically synthesized silver nanoparticles (bio-AgNPs) have been frequently used due to their unique physicochemical properties that result not only from their shape and size but also from surface coatings of natural origin. These properties determine antibacterial, antifungal, antiprotozoal, anticancer, anti-inflammatory, and many more activities of bio-AgNPs. This review provides the current state of knowledge on the methods and mechanisms of biogenic synthesis of silver nanoparticles as well as their potential applications in different fields such as medicine, food, agriculture, and industries.

Efficient biodegradation of Congo red dye using fungal consortium incorporated with Penicillium oxalicum and Aspergillus tubingensis

A novel approach had been carried out to develop fungal consortium, namely, RH-2, containing two marine procured fungal isolates in order to evaluate biodegradation of recalcitrant diazo dye Congo red. The fungi were isolated from the seacoast of Diu, India. According to the ITS sequencing, the strains were identified as Penicillium oxalicum (DS-2) and Aspergillus tubingensis (DS-4). Discs of 12 mm were cut out from the edge of both the fungal isolates (DS-2 and DS-4) and inoculated in flasks consisting of potato dextrose broth with 100 mg/L Congo red for the development of fungal consortium RH-2. The degradation by the fungal consortium RH-2 was more effective than the fungal monocultures DS-2 and DS-4 with the respective degradation reaching 97.15 ± 0.15%, 68.96 ± 0.09%, and 29.96 ± 0.21% in addition of yeast extract (1% w/v) within 12 h. The influence of dextrose (1% w/v), yeast extract (1% w/v), pH 5, and salt concentration (1% w/v) enhanced the degradation potential of fungal consortium RH-2. The maximal degradation was correlated with the production of laccase (12.498 ± 0.21 U/mL) and manganese peroxidase (10.314 ± 0.25 U/mL). The catabolism of Congo red was confirmed by UV-Visible spectroscopic analysis (Congo red λ-max = 499 nm) and ATR-FTIR spectroscopic analysis. The filtrates obtained after Congo red degradation were also evaluated for microbial toxicity against bacteria (Bacillus haynesii) and phytotoxicity analysis on plant seed (Trigonella foenum) which revealed that the filtrate acquired after the treatment of Congo red by fungal consortium RH-2 was less toxic than the original dye in nature. A novel aspect is determined by the evidence of mutualistic interaction between two different fungi for the rapid decolorization and degradation of dye providing a prospective of utilizing the developed consortium RH-2 as a cost-effective approach in textile wastewater treatment for cleaner environment.

Antioxidants: Classification, Natural Sources, Activity/Capacity Measurements, and Usefulness for the Synthesis of Nanoparticles

Natural extracts are the source of many antioxidant substances. They have proven useful not only as supplements preventing diseases caused by oxidative stress and food additives preventing oxidation but also as system components for the production of metallic nanoparticles by the so-called green synthesis. This is important given the drastically increased demand for nanomaterials in biomedical fields. The source of ecological technology for producing nanoparticles can be plants or microorganisms (yeast, algae, cyanobacteria, fungi, and bacteria). This review presents recently published research on the green synthesis of nanoparticles. The conditions of biosynthesis and possible mechanisms of nanoparticle formation with the participation of bacteria are presented. The potential of natural extracts for biogenic synthesis depends on the content of reducing substances. The assessment of the antioxidant activity of extracts as multicomponent mixtures is still a challenge for analytical chemistry. There is still no universal test for measuring total antioxidant capacity (TAC). There are many in vitro chemical tests that quantify the antioxidant scavenging activity of free radicals and their ability to chelate metals and that reduce free radical damage. This paper presents the classification of antioxidants and non-enzymatic methods of testing antioxidant capacity in vitro, with particular emphasis on methods based on nanoparticles. Examples of recent studies on the antioxidant activity of natural extracts obtained from different species such as plants, fungi, bacteria, algae, lichens, actinomycetes were collected, giving evaluation methods, reference antioxidants, and details on the preparation of extracts.

Myco-nanotechnological approach to synthesize silver oxide nanocuboids using endophytic fungus isolated from Citrus pseudolimon plant

The current study reports the isolation of Colletotrichum plurivorum, an endophytic fungus from a Citrus pseudolimon plant and its utilization in the green synthesis of silver oxide nanocuboids (Ag₂O NCs) at room temperature. The synthesized nanocrystals were thoroughly characterized by UV-vis, FTIR spectroscopy, field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), X-ray diffraction (XRD) analyses. Electron microscopic images confirmed the formation of cuboid shaped particles having size 200-250 nm in length and 80-150 nm in width, whereas, XRD and selected area electron diffraction (SAED) pattern confirms the formation of cubic Ag₂O nanocrystals. Then these Ag₂O NCs are applied in antibacterial activities against a pathogenic gram-negative bacteria Escherichia coli and gram-positive bacteria Bacillus subtilis and found very good activities against them. Currently these types of nanocuboids have drawn great interest in the field of catalysis, photocatalysis to biomedical applications.

Metal-Fungus interaction: Review on cellular processes underlying heavy metal detoxification and synthesis of metal nanoparticles

The most adverse outcome of increasing industrialization is contamination of the ecosystem with heavy metals. Toxic heavy metals possess a deleterious effect on all forms of biota; however, they affect the microbial system directly. These heavy metals form complexes with the microbial system by forming covalent and ionic bonds and affecting them at the cellular level and biochemical and molecular levels, ultimately leading to mutation affecting the microbial population. Microbes, in turn, have developed efficient resistance mechanisms to cope with metal toxicity. This review focuses on the vital tolerance mechanisms employed by the fungus to resist the toxicity caused by heavy metals. The tolerance mechanisms have been basically categorized into biosorption, bioaccumulation, biotransformation, and efflux of metal ions. The mechanisms of tolerance to some toxic metals as copper, arsenic, zinc, cadmium, and nickel have been discussed. The article summarizes and provides a detailed illustration of the tolerance means with specific examples in each case. Exposure of metals to fungal cells leads to a response that may lead to the formation of metal nanoparticles to overcome the toxicity by immobilization in less toxic forms. Therefore, fungal-mediated green synthesis of metal nanoparticles, their mechanism of synthesis, and applications have also been discussed. An understanding of how fungus resists metal toxicity can provide insights into the development of adaption techniques and methodologies for detoxification and removal of metals from the environment.

Application of a marine luminescent Vibrio sp. B4L for biosynthesis of silver nanoparticles with unique characteristics, biochemical properties, antibacterial and antibiofilm activities

Biosynthesis of silver nanoparticles (AgNPs) by marine bacteria especially luminescent Vibrio species is least investigated. In this study, AgNPs were first synthesized by the culture supernatant of a luminescent bacterium (Vibrio sp. B4L) and then, the prepared samples were characterized employing several techniques. The antibacterial activity of the AgNPs was investigated against Escherichia coli and Staphylococcus aureus using disk diffusion agar and broth microdilution methods. The growth curve, Reactive Oxygen Species (ROS) formation, and Lactate Dehydrogenase (LDH) activity of the samples were measured along with Field Emission Scanning Electron Microscopy (FESEM) observation and inhibition of biofilm formation. Dynamic light scattering (DLS) analysis showed that the average particle size of the synthesized AgNPs was in the range of about 32.67-107.18 nm and the polydispersity index (PDI) of 0.1120 indicated the formation of monodispersed particles. The average zeta potential of AgNPs obtained -36.15 mV, showing the high stability of biosynthetic nanoparticles. Antibacterial studies indicated that not only the AgNPs had antibacterial activity but also increased the antibacterial properties of tetracycline when used in combination. ROS production was enhanced in a dose-dependent manner. A high difference in LDH activities was found between AgNPs treated cells and the control group. FESEM images revealed membrane disruption and lysis in AgNPs treated cells. The formation of E. coli biofilm was 100% inhibited at 62.5 µg/ml showing that our bacteriogenic AgNPs can be a potential alternative remedies for controlling antibiotic-resistant pathogens.

Isolation and Optimization of Culture Conditions of Thraustochytrium kinnei for Biomass Production, Nanoparticle Synthesis, Antioxidant and Antimicrobial Activities

This work deals with the identification of a predominant thraustochytrid strain, the optimization of culture conditions, the synthesis of nanoparticles, and the evaluation of antioxidant and antimicrobial activities in biomass extracts and nanoparticles. Thraustochytrium kinnei was identified as a predominant strain from decomposing mangrove leaves, and its culture conditions were optimized for maximum biomass production of 13.53 g·L−1, with total lipids of 41.33% and DHA of 39.16% of total fatty acids. Furthermore, the strain was shown to synthesize gold and silver nanoparticles in the size ranges of 10–85 nm and 5–90 nm, respectively. Silver nanoparticles exhibited higher total antioxidant and DPPH activities than gold nanoparticles and methanol extract of the strain. The silver nanoparticles showed higher antimicrobial activity than gold nanoparticles and petroleum ether extract of the strain. Thus, Thraustochytrium kinnei is proven to be promising for synthesis of silver nanoparticles with high antioxidant and antimicrobial activity.

Synthesis and modification of bio-derived antibacterial Ag and ZnO nanoparticles by plants, fungi, and bacteria

Ag and ZnO nanoparticles (NP) can be prepared by physical, chemical, or eco-friendly methods. The biosynthesis of metal and metal oxide NPs by plants, fungi, and bacteria could be a promising way to obtain biocompatible NPs that have desirable antibacterial activities. However, the uniformity of shape, size, and size distribution of NPs are crucial to producing significant antibacterial results, particularly in physiological conditions such as infected wounds or septicemia. In this review, we discuss recent progress and challenges in the use of novel approaches for the biosynthesis of Ag and ZnO nanoparticles that have antibacterial activities.

Biogenic Nanoparticles: Synthesis, Characterisation and Applications

Nanotechnology plays a big part in our modern daily lives, ranging from the biomedical sector to the energy sector. There are different physicochemical and biological methods to synthesise nanoparticles towards multiple applications. Biogenic production of nanoparticles through the utilisation of microorganisms provides great advantages over other techniques and is increasingly being explored. This review examines the process of the biogenic synthesis of nanoparticles mediated by microorganisms such as bacteria, fungi and algae, and their applications. Microorganisms offer a disparate environment for nanoparticle synthesis. Optimum production and minimum time to obtain the desired size and shape, to improve the stability of nanoparticles and to optimise specific microorganisms for specific applications are the challenges to address, however. Numerous applications of biogenic nanoparticles in medicine, environment, drug delivery and biochemical sensors are discussed.

Bioavailability and antioxidant activity of nanotechnology-based botanic antioxidants

Botanic bioactive substances have issues with their solubility, stability, and oral bioavailability in the application, which could be improved by nanotechnologies. In another hands, green synthesis of nanoparticles (NPs) with plant extract is also a promising technology for preparation of NPs due to its safety advantage, yet the bioactive botanic substances that could be more than the assistant of the green synthesis of NPs. Based on the above concerns, this review summarized the preparation of botanic NPs with various plant extract, their solubility, stability, and oral bioavailability; specific attention has been paid to the botanic Ag/Au NPs, their capacity of antioxidant, bioavailability, antimicrobial, anti-inflammatory, and anticancer.

Biogenically proficient synthesis and characterization of silver nanoparticles employing marine procured fungi Aspergillus brunneoviolaceus along with their antibacterial and antioxidative potency

OBJECTIVES

To assess the extracellular synthesis of silver nanoparticles using marine derived fungi Aspergillus brunneoviolaceus with their antibacterial and antioxidant activities.

RESULTS

The biosynthesis of silver nanoparticles was estimated by the change in color from light yellow to dark brown within 36 h as the reaction progressed. UV-Visible spectroscopy exhibited its stability at 411 nm; ATR-FTIR spectroscopy depicted the functional group responsible for its production; X-Ray Diffraction denoted its crystalline FCC structure resembling the peaks in XRD pattern, corresponding to [111], [200], [220], [311] and [222] planes; TEM imaging revealed its spherical morphology with the particle size ranging from 0.72 to 15.21 nm and Tauc's plot analysis that disclosed its band gap energy as 2.44 eV that manifested the potential of AgNPs to be semiconductors. The characterization data henceforth, confirmed the efficient production of silver nanoparticles. The biosynthesized AgNPs expressed strong antibacterial activity against two Gram-positive and three Gram-negative bacteria. They also proved to possess higher antioxidative potentials by showing their potent radical scavenging activity against DPPH (2, 2-diphenyl-1-picrylhydrazyl).

CONCLUSIONS

The study unfolds the prospect for further utilization of this mycogenically synthesized AgNPs as antibacterial, antioxidative and anticancer agents.

Antioxidant Functionalized Nanoparticles: A Combat against Oxidative Stress

Numerous abiotic stresses trigger the overproduction of reactive oxygen species (ROS) that are highly toxic and reactive. These ROS are known to cause damage to carbohydrates, DNA, lipids and proteins, and build the oxidative stress and results in the induction of various diseases. To resolve this issue, antioxidants molecules have gained significant attention to scavenge these free radicals and ROS. However, poor absorption ability, difficulty in crossing the cell membranes and degradation of these antioxidants during delivery are the few challenges associated with both natural and synthetic antioxidants that limit their bioavailability. Moreover, the use of nanoparticles as an antioxidant is overlooked, and is limited to a few nanomaterials. To address these issues, antioxidant functionalized nanoparticles derived from various biological origin have emerged as an important alternative, because of properties like biocompatibility, high stability and targeted delivery. Algae, bacteria, fungi, lichens and plants are known as the producers of diverse secondary metabolites and phenolic compounds with extraordinary antioxidant properties. Hence, these compounds could be used in amalgamation with biogenic derived nanoparticles (NPs) for better antioxidant potential. This review intends to increase our knowledge about the antioxidant functionalized nanoparticles and the mechanism by which antioxidants empower nanoparticles to combat oxidative stress.