Microbial synthesis of semiconductor CdS nanoparticles, their characterization, and their use in the fabrication of an ideal diode

Effects of environmental metal and metalloid pollutants on plants and human health: exploring nano-remediation approach

Metal and metalloid pollutants severely threatens environmental ecosystems and human health, necessitating effective remediation strategies. Nanoparticle (NPs)-based approaches have gained significant attention as promising solutions for efficient removing heavy metals from various environmental matrices. The present review is focused on green synthesized NPs-mediated remediation such as the implementation of iron, carbon-based nanomaterials, metal oxides, and bio-based NPs. The review also explores the mechanisms of NPs interactions with heavy metals, including adsorption, precipitation, and redox reactions. Critical factors influencing the remediation efficiency, such as NPs size, surface charge, and composition, are systematically examined. Furthermore, the environmental fate, transport, and potential risks associated with the application of NPs are critically evaluated. The review also highlights various sources of metal and metalloid pollutants and their impact on human health and translocation in plant tissues. Prospects and challenges in translating NPs-based remediation from laboratory research to real-world applications are proposed. The current work will be helpful to direct future research endeavors and promote the sustainable implementation of metal and metalloid elimination.

Diversity of Mycogenic Oxide and Chalcogenide Nanoparticles: A Review

Oxide and chalcogenide nanoparticles have great potential for use in biomedicine, engineering, agriculture, environmental protection, and other research fields. The myco-synthesis of nanoparticles with fungal cultures, their metabolites, culture liquids, and mycelial and fruit body extracts is simple, cheap and environmentally friendly. The characteristics of nanoparticles, including their size, shape, homogeneity, stability, physical properties and biological activity, can be tuned by changing the myco-synthesis conditions. This review summarizes the data on the diversity of oxide and chalcogenide nanoparticles produced by various fungal species under different experimental conditions.

Plant and Microbial Approaches as Green Methods for the Synthesis of Nanomaterials: Synthesis, Applications, and Future Perspectives

The unique biological and physicochemical characteristics of biogenic (green-synthesized) nanomaterials (NMs) have attracted significant interest in different fields, with applications in the agrochemical, food, medication delivery, cosmetics, cellular imaging, and biomedical industries. To synthesize biogenic nanomaterials, green synthesis techniques use microorganisms, plant extracts, or proteins as bio-capping and bio-reducing agents and their role as bio-nanofactories for material synthesis at the nanoscale size. Green chemistry is environmentally benign, biocompatible, nontoxic, and economically effective. By taking into account the findings from recent investigations, we shed light on the most recent developments in the green synthesis of nanomaterials using different types of microbes and plants. Additionally, we cover different applications of green-synthesized nanomaterials in the food and textile industries, water treatment, and biomedical applications. Furthermore, we discuss the future perspectives of the green synthesis of nanomaterials to advance their production and applications.

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.

Fungal- and Algal-Derived Synthesis of Various Nanoparticles and Their Applications

Nanoparticles synthesis through biological mediated methods with a particular focus on the processes mediated by fungi and algae is discussed, which systematically reviews nanoparticle characterization, composition, synthesis methods, and, lastly but not least, the applications of NPs across five different categories to provide a reference for future research. Most traditional methods to generate nanoparticles have certain limitations, like the toxicity of precursor materials, the need for high-temperature management, and the high cost of synthesis, which ultimately hinders their utility in sectors. Greener synthesis through fungus and algae done through bioreduction by biomolecules or enzymes present in them is low-energy, low-cost, and needs a low-temperature environment, providing a unique technique for the manufacture of various metallic nanoparticles utilized in an array of industries and healthcare.

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

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

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.

Silver Nanoparticle Production Mediated by Vitis vinifera Cane Extract: Characterization and Antibacterial Activity Evaluation

The ever-growing range of possible applications of nanoparticles requires their mass production. However, there are problems resulting from the prevalent methods of nanoparticle production; physico-chemical routes of nanoparticle synthesis are not very environmentally friendly nor cost-effective. Due to this, the scientific community started exploring new methods of nanoparticle assembly with the aid of biological agents. In this study, ethanolic Vitis vinifera cane extract combined with silver nitrate was used to produce silver nanoparticles. These were subsequently characterized using UV-visible (UV-Vis) spectrometry, transmission electron microscopy, and dynamic light-scattering analysis. The antimicrobial activity of produced nanoparticles was tested against the planktonic cells of five strains of Gram-negative bacterium Pseudomonas aeruginosa (PAO1, ATCC 10145, ATCC 15442, DBM 3081, and DBM 3777). After that, bactericidal activity was assessed using solid medium cultivation. In the end, nanoparticles’ inhibitory effect on adhering cells was analyzed by measuring changes in metabolic activity (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay-MTT). Our results confirmed that ethanolic Vitis vinifera cane extract is capable of mediating silver nanoparticle production; synthesis was conducted using 10% of extract and 1 mM of silver nitrate. The silver nanoparticles’ Z-average was 68.2 d nm, and their zeta potential was –30.4 mV. These silver nanoparticles effectively inhibited planktonic cells of all P. aeruginosa strains in concentrations less than 5% v/v and inhibited biofilm formation in concentrations less than 6% v/v. Moreover, minimum bactericidal concentration was observed to be in the range of 10–16% v/v. According to the results in this study, the use of wine agriculture waste is an ecological and economical method for the production of silver nanoparticles exhibiting significant antimicrobial properties.

Biogenic Sulfur-Based Chalcogenide Nanocrystals: Methods of Fabrication, Mechanistic Aspects, and Bio-Applications

Bio-nanotechnology has emerged as an efficient and competitive methodology for the production of added-value nanomaterials (NMs). This review article gathers knowledge gleaned from the literature regarding the biosynthesis of sulfur-based chalcogenide nanoparticles (S-NPs), such as CdS, ZnS and PbS NPs, using various biological resources, namely bacteria, fungi including yeast, algae, plant extracts, single biomolecules, and viruses. In addition, this work sheds light onto the hypothetical mechanistic aspects, and discusses the impact of varying the experimental parameters, such as the employed bio-entity, time, pH, and biomass concentration, on the obtained S-NPs and, consequently, on their properties. Furthermore, various bio-applications of these NMs are described. Finally, key elements regarding the whole process are summed up and some hints are provided to overcome encountered bottlenecks towards the improved and scalable production of biogenic S-NPs.

Marine Macroalgae Display Bioreductant Efficacy for Fabricating Metallic Nanoparticles: Intra/Extracellular Mechanism and Potential Biomedical Applications

The application of hazardous chemicals during nanoparticle (NP) synthesis has raised alarming concerns pertaining to their biocompatibility and equally to the environmental harmlessness. In the recent decade, nanotechnological research has made a gigantic shift in order to include the natural resources to produce biogenic NPs. Within this approach, researchers have utilized marine resources such as macroalgae and microalgae, land plants, bacteria, fungi, yeast, actinomycetes, and viruses to synthesize NPs. Marine macroalgae (brown, red, and green) are rich in polysaccharides including alginates, fucose-containing sulfated polysaccharides (FCSPs), galactans, agars or carrageenans, semicrystalline cellulose, ulvans, and hemicelluloses. Phytochemicals are abundant in phenols, tannins, alkaloids, terpenoids, and vitamins. However, microorganisms have an abundance of active compounds ranging from sugar molecules, enzymes, canonical membrane proteins, reductase enzymes (NADH and NADPH), membrane proteins to many more. The prime reason for using the aforesaid entities in the metallic NPs synthesis is based on their intrinsic properties to act as bioreductants, having the capability to reduce and cap the metal ions into stabilized NPs. Several green NPs have been verified for their biocompatibility in human cells. Bioactive constituents from the above resources have been found on the green metallic NPs, which has demonstrated their efficacies as prospective antibiotics and anti-cancer agents against a range of human pathogens and cancer cells. Moreover, these NPs can be characterized for the size, shapes, functional groups, surface properties, porosity, hydrodynamic stability, and surface charge using different characterization techniques. The novelty and originality of this review is that we provide recent research compilations on green synthesis of NPs by marine macroalgae and other biological sources (plant, bacteria, fungi, actinomycetes, yeast, and virus). Besides, we elaborated on the detailed intra- and extracellular mechanisms of NPs synthesis by marine macroalgae. The application of green NPs as anti-bacterial, anti-cancer, and popular methods of NPs characterization techniques has also been critically reviewed.

Current advances in bio-fabricated quantum dots emphasising the study of mechanisms to diversify their catalytic and biomedical applications

Quantum dots (QDs), owing to their single atom-like electronic structure due to quantum confinement, are often referred to as artificial atoms. This unique physical property results in the diverse functions exhibited by QDs. A wide array of applications have been achieved by the surface functionalization of QDs, resulting in exceptional optical, antimicrobial, catalytic, cytotoxic and enzyme inhibition properties. Ordinarily, traditionally prepared QDs are subjected to post synthesis functionalization via a variety of methods, such as ligand exchange or covalent and non-covalent conjugation. Nevertheless, solvent toxicity, combined with the high temperature and pressure conditions during the preparation of QDs and the low product yield due to multiple steps in the functionalization, limit their overall use. This has driven scientists to investigate the development of greener, environmental friendly and cost-effective methods that can circumvent the complexity and strenuousness associated with traditional processes of bio-functionalization. In this review, a detailed analysis of the methods to bio-prepare pre-functionalized QDs, with elucidated mechanisms, and their application in the areas of catalysis and biomedical applications has been conducted. The environmental and health and safety aspects of the bio-derived QDs have been briefly discussed to unveil the future of nano-commercialization.

Zinc phosphate nanoparticles: A review on physical, chemical, and biological synthesis and their applications

Nanotechnology is considered one of the emerging fields of science that has influenced diverse applications, including food, biomedicine, and cosmetics. The production and usage of materials with nanoscale dimensions like nanoparticles are attractive parts of nanotechnology. Among different nanoparticles, zinc phosphate nanoparticles have attracted attention due to their biocompatibility, biosafety, non-toxicity, and environmental compatibility. These nanoparticles could be employed in various applications like anticorrosion, antibacterial, dental cement, glass ceramics, tissue engineering, and drug delivery. A variety of physical, chemical, and green synthesis methods have been used to synthesize zinc phosphate nanoparticles. All these methods have some limitations along with certain advantages. Chemical approaches may cause health risks and environmental problems due to the toxicity of hazardous chemicals used in these techniques. Moreover, physical methods require high amounts of energy as well as expensive instruments. However, biological methods are free of chemical contaminants and eco-friendly. This review is aimed to explore different methods for the synthesis of zinc phosphate nanoparticles, including physical, chemical, and more recently, biological approaches (using various sources such as plants, algae, and microorganisms). Also, it summarizes the practicable applications of zinc phosphate nanoparticles as anticorrosion pigment, dental cement, and drug delivery agents.

Artificial-regulated synthesis of nanocrystals in live cells

Live cells, as reservoirs of biochemical reactions, can serve as amazing integrated chemical plants where precursor formation, nucleation and growth of nanocrystals, and functional assembly can be carried out accurately following an artificial program. It is crucial but challenging to deliberately direct intracellular pathways to synthesize desired nanocrystals that cannot be produced naturally in cells, because the relevant reactions exist in different spatiotemporal dimensions and will never encounter spontaneously. This article summarizes progress in the introduction of inorganic functional nanocrystals into live cells via the ‘artificial-regulated space–time-coupled live-cell synthesis’ strategy. We also describe ingenious bio-applications of the nanocrystal–cell systems, and quasi-biosynthesis strategies expanded from live-cell synthesis. Artificial-regulated live-cell synthesis—which involves the interdisciplinary application of biology, chemistry, nanoscience and medicine—will enable researchers to better exploit the unanticipated potentialities of live cells and open up new directions in synthetic biology.

Green Synthesis of Nanomaterials

Nanotechnology is considered one of the paramount forefronts in science over the last decade. Its versatile implementations and fast-growing demand have paved the way for innovative measures for the synthesis of higher quality nanomaterials. In the early stages, traditional synthesis methods were utilized, and they relied on both carcinogenic chemicals and high energy input for production of nano-sized material. The pollution produced as a result of traditional synthesis methods induces a need for environmentally safer synthesis methods. As the downfalls of climate change become more abundant, the scientific community is persistently seeking solutions to combat the devastation caused by toxic production methods. Green methods for nanomaterial synthesis apply natural biological systems to nanomaterial production. The present review highlights the history of nanoparticle synthesis, starting with traditional methods and progressing towards green methods. Green synthesis is a method just as effective, if not more so, than traditional synthesis; it provides a sustainable approach to nanomaterial manufacturing by using naturally sourced starting materials and relying on low energy processes. The recent use of active molecules in natural biological systems such as bacteria, yeast, algae and fungi report successful results in the synthesis of various nanoparticle systems. Thus, the integration of green synthesis in scientific research and mass production provides a potential solution to the limitations of traditional synthesis methods.

Intracellular Hybrid Biosystem in a Protozoan to Trigger Visible-Light-Driven Photocatalysis

Incorporating artificial photosensitizers with microorganisms has recently been recognized as an effective way to convert light energy into chemical energy. However, the incorporated biosystem is usually constructed in an extracellular manner and is vulnerable to the external environment. Here, we develop an intracellular hybrid biosystem in a higher organism protozoa Tetrahymena pyriformis, in which the in vivo synthesized CdS nanoparticles trigger photoreduction of nitrobenzene into aniline under visible-light irradiation. Integrating a photosensitizer CdS into T. pyriformis enables the photosensitizer CdS, inherent nitroreductase, and the cytoplasmic reductive substance in T. pyriformis to synergistically engage in the photocatalysis process, generating a greatly enhanced aniline yield with a 40-fold increment. Moreover, building an intracellular hybrid biosystem in mutant T. pyriformis could even grant it new capability of reducing nitrobenzene into aniline under visible-light irradiation. Such an intracellular hybrid biosystem paves a new way to functionalize higher organisms and diversify light energy conversion.

Microencapsulation of biosynthesized zinc oxide nanoparticles (ZnO-NPs) using Plumeria leaf extract and kinetic studies in the release of ZnO-NPs from microcapsules

Biosynthesis using plant extract is known as one of the potential techniques to synthesize different zinc oxide nanoparticles (ZnO-NPs) in different size ranges. ZnO-NPs were synthesized using Plumeria leaf extract with laboratory chemical reagent Zn(CH3COO)2 and followed by the micro-encapsulation of biosynthesized ZnO-NPs using chitosan and cellulose with TEOF as a cross-linker employing freeze gelation method. Both neat and encapsulated ZnO-NPs have been characterized by FT-IR, UV spectroscopy, XRD, and SEM techniques. The UV-spectroscopic analysis confirmed the characteristic band of ZnO-NPs at 356.0 nm, and FIIR showed the peaks at 544 cm−1 and 545 cm−1 corresponding to the Zn–O bond. Powder XRD pattern showed the wurtzite structure of ZnO and gave the calculated average crystallite size as of 27.23 nm. In the case of encapsulated ZnO-NPs, the UV–visible spectrum showed two strong absorption peaks at 232.5 nm, 242.5 nm, and a weak peak at 357 nm. A broad peak at 3333 cm−1 in FT-IR spectra is either due to N–H stretching in the amide group of chitosan or hydroxyl group in encapsulated ZnO-NPs. It was observed that chitosan loaded ZnO-NPs had higher entrapment efficiency (81.98%) at 15 mL of plant extract. The kinetic profile in the release of ZnO particles out from encapsulated ZnO-NPs was observed to follow four kinetic paths in 120 min at pH 1.2. The particle release followed the zero-order kinetic in the first 50 min and then followed by Hixson–Crowell kinetic in the next 50 min with two different rate constants, 2.6 × 10−3 min−1 and 13 × 10−3 min−1, before it backs to the zero-order kinetics. This study shows that ZnO nanoparticles can easily be biosynthesized and encapsulated for use in the pharmaceutical industry.

Integrating biometallurgical recovery of metals with biogenic synthesis of nanoparticles

Industrial activities, such as mining, electroplating, cement production, and metallurgical operations, as well as manufacturing of plastics, fertilizers, pesticides, batteries, dyes or anticorrosive agents, can cause metal contamination in the surrounding environment. This is an acute problem due to the non-biodegradable nature of metal pollutants, their transformation into toxic and carcinogenic compounds, and bioaccumulation through the food chain. At the same time, platinum group metals and rare earth elements are of strong economic interest and their recovery is incentivized. Microbial interaction with metals or metals-bearing minerals can facilitate metals recovery in the form of nanoparticles. Metal nanoparticles are gaining increasing attention due to their unique characteristics and application as antimicrobial and antibiofilm agents, biocatalysts, in targeted drug delivery, for wastewater treatment, and in water electrolysis. Ideally, metal nanoparticles should be homogenous in shape and size, and not toxic to humans or the environment. Microbial synthesis of nanoparticles represents a safe, and environmentally friendly alternative to chemical and physical methods. In this review article, we mainly focus on metal and metal salts nanoparticles synthesized by various microorganisms, such as bacteria, fungi, microalgae, and yeasts, as well as their advantages in biomedical, health, and environmental applications.

Green Synthesis of Metallic Nanoparticles and Their Potential Applications to Treat Cancer

Nanoparticle synthesis using microorganisms and plants by green synthesis technology is biologically safe, cost-effective, and environment-friendly. Plants and microorganisms have established the power to devour and accumulate inorganic metal ions from their neighboring niche. The biological entities are known to synthesize nanoparticles both extra and intracellularly. The capability of a living system to utilize its intrinsic organic chemistry processes in remodeling inorganic metal ions into nanoparticles has opened up an undiscovered area of biochemical analysis. Nanotechnology in conjunction with biology gives rise to an advanced area of nanobiotechnology that involves living entities of both prokaryotic and eukaryotic origin, such as algae, cyanobacteria, actinomycetes, bacteria, viruses, yeasts, fungi, and plants. Every biological system varies in its capabilities to supply metallic nanoparticles. However, not all biological organisms can produce nanoparticles due to their enzymatic activities and intrinsic metabolic processes. Therefore, biological entities or their extracts are used for the green synthesis of metallic nanoparticles through bio-reduction of metallic particles leading to the synthesis of nanoparticles. These biosynthesized metallic nanoparticles have a range of unlimited pharmaceutical applications including delivery of drugs or genes, detection of pathogens or proteins, and tissue engineering. The effective delivery of drugs and tissue engineering through the use of nanotechnology exhibited vital contributions in translational research related to the pharmaceutical products and their applications. Collectively, this review covers the green synthesis of nanoparticles by using various biological systems as well as their applications.

Eco friendly silver nanoparticles synthesis by Brassica oleracea and its antibacterial, anticancer and antioxidant properties

Production of environmentally amenable silver nanoparticles (AgNPs) has garnered the interest of the scientific community owing to their broad application primarily in the field of optronics, sensing and extensively in pharmaceuticals as promising antioxidant, antimicrobial and anticancer agents. The current study emphases on production of ecofriendly silver nanoparticles from Brassica oleracea (BO) and investigated their antibacterial, anticancer and antioxidant activity. The characteristics of synthesized BO-AgNPs were studied by ultraviolet-visible spectroscopy, particle size analysis, electro kinetic/zeta potential analysis, and Transmission electron microscope (TEM). A distinctive absorption maximum at 400 nm confirmed the formation of BO-AgNPs and data on TEM analysis have shown that the synthesized nanoparticles were predominantly spherical in shape. The BO-AgNPs obtained were assessed for antibacterial, antioxidant, and cytotoxic ability in MCF-7 cells. The antibacterial activity expressed was maximum against Staphylococcus epidermidis (Gram positive) and Pseudomonas aeruginosa (Gram negative) with DIZ of 14.33 ± 0.57 and 12.0 ± 0.20 mm respectively. Furthermore, the ability of the synthesized green nanoparticles to scavenge free radicals revealed a strong antioxidant activity. The cytotoxicity increased proportionately with increasing concentration of the green synthesized BO-AgNPs with maximum effect at 100 μg/ml and IC50 of 55 μg/ml. In conclusion, the data obtained in the study is reflective of the role of BO-AgNPs as potential and promising antimicrobial agent against bacterial infections and potential anticancer agent in cancer therapy.

In Vivo Biosynthesis of Inorganic Nanomaterials Using Eukaryotes-A Review

Bionanotechnology, the use of biological resources to produce novel, valuable nanomaterials, has witnessed tremendous developments over the past two decades. This eco-friendly and sustainable approach enables the synthesis of numerous, diverse types of useful nanomaterials for many medical, commercial, and scientific applications. Countless reviews describing the biosynthesis of nanomaterials have been published. However, to the best of our knowledge, no review has been exclusively focused on the in vivo biosynthesis of inorganic nanomaterials. Therefore, the present review is dedicated to filling this gap by describing the many different facets of the in vivo biosynthesis of nanoparticles (NPs) using living eukaryotic cells and organisms-more specifically, live plants and living biomass of several species of microalgae, yeast, fungus, mammalian cells, and animals. It also highlights the strengths and weaknesses of the synthesis methodologies and the NP characteristics, bio-applications, and proposed synthesis mechanisms. This comprehensive review also brings attention to enabling a better understanding between the living organisms themselves and the synthesis conditions that allow their exploitation as nanobiotechnological production platforms as these might serve as a robust resource to boost and expand the bio-production and use of desirable, functional inorganic nanomaterials.

A Brief Overview on Antioxidant Activity Determination of Silver Nanoparticles

Our objective in this review article is to find out relevant information about methods of determination of antioxidant activity of silver nanoparticles. There are many studies dealing with mentioned problem and herein we summarize the knowledge about methods evaluating the antioxidant activity of silver nanoparticles reported so far. Many authors declare better antioxidant activity of silver nanoparticles compared to the extract used for synthesis of them. In this review, we focused on methods of antioxidant activity determination in detail to find out novel and perspective techniques to solve the general problems associated with the determination of antioxidant activity of silver nanoparticles.

Advancements in Plant and Microbe-Based Synthesis of Metallic Nanoparticles and Their Antimicrobial Activity against Plant Pathogens

A large number of metallic nanoparticles have been successfully synthesized by using different plant extracts and microbes including bacteria, fungi viruses and microalgae. Some of these metallic nanoparticles showed strong antimicrobial activities against phytopathogens. Here, we summarized these green-synthesized nanoparticles from plants and microbes and their applications in the control of plant pathogens. We also discussed the potential deleterious effects of the metallic nanoparticles on plants and beneficial microbial communities associated with plants. Overall, this review calls for attention regarding the use of green-synthesized metallic nanoparticles in controlling plant diseases and clarification of the risks to plants, plant-associated microbial communities, and environments before using them in agriculture.

Biomineralized nanosilica-based organelles endow living yeast cells with non-inherent biological functions

We propose a biomimetic strategy to construct engineered yeast cells (EYCs) by building intracellular silica nanoscaffolds as biomimetic organelles. These nanosilica-based organelles can coordinate with loaded drug and yeast as a shell could prevent drug leakage. In vivo results show that EYCs serve as a dually responsive drug delivery system, targeted with extracellular caps (folate) and triggered by intracellular SiO2 at the low pH of cancer tissue.

Cytotoxicity of NiO and Ni(OH)2 Nanoparticles Is Mediated by Oxidative Stress-Induced Cell Death and Suppression of Cell Proliferation

The use of nanomaterial-based products continues to grow with advancing technology. Understanding the potential toxicity of nanoparticles (NPs) is important to ensure that products containing them do not impose harmful effects to human or environmental health. In this study, we evaluated the comparative cytotoxicity between nickel oxide (NiO) and nickel hydroxide (Ni(OH)₂) in human bronchoalveolar carcinoma (A549) and human hepatocellular carcinoma (HepG2) cell lines. Cellular viability studies revealed cell line-specific cytotoxicity in which nickel NPs were toxic to A549 cells but relatively nontoxic to HepG2 cells. Time-, concentration-, and particle-specific cytotoxicity was observed in A549 cells. NP-induced oxidative stress triggered dissipation of mitochondrial membrane potential and induction of caspase-3 enzyme activity. The subsequent apoptotic events led to reduction in cell number. In addition to cell death, suppression of cell proliferation played an essential role in regulating cell number. Collectively, the observed cell viability is a function of cell death and suppression of proliferation. Physical and chemical properties of NPs such as total surface area and metal dissolution are in agreement with the observed differential cytotoxicity. Understanding the properties of NPs is essential in informing the design of safer materials.

Differential Cytotoxicity Induced by Transition Metal Oxide Nanoparticles is a Function of Cell Killing and Suppression of Cell Proliferation

The application of nanoparticles (NPs) in industry is on the rise, along with the potential for human exposure. While the toxicity of microscale equivalents has been studied, nanoscale materials exhibit different properties and bodily uptake, which limits the prediction ability of microscale models. Here, we examine the cytotoxicity of seven transition metal oxide NPs in the fourth period of the periodic table of the chemical elements. We hypothesized that NP-mediated cytotoxicity is a function of cell killing and suppression of cell proliferation. To test our hypothesis, transition metal oxide NPs were tested in a human lung cancer cell model (A549). Cells were exposed to a series of concentrations of TiO₂, Cr₂O₃, Mn₂O₃, Fe₂O₃, NiO, CuO, or ZnO for either 24 or 48 h. All NPs aside from Cr₂O₃ and Fe₂O₃ showed a time- and dose-dependent decrease in viability. All NPs significantly inhibited cellular proliferation. The trend of cytotoxicity was in parallel with that of proliferative inhibition. Toxicity was ranked according to severity of cellular responses, revealing a strong correlation between viability, proliferation, and apoptosis. Cell cycle alteration was observed in the most toxic NPs, which may have contributed to promoting apoptosis and suppressing cell division rate. Collectively, our data support the hypothesis that cell killing and cell proliferative inhibition are essential independent variables in NP-mediated cytotoxicity.

Escherichia coli-based synthesis of cadmium sulfide nanoparticles, characterization, antimicrobial and cytotoxicity studies

The present research describes the synthesis of cadmium sulfide (CdS) nanoparticles from Escherichia coli under the influence of bacterial enzyme sulphate reductase and study on their cytotoxicity for applications in cancer therapy. Escherichia coli cells were used to synthesize CdS nanoparticles under different concentrations of cadmium chloride and sodium sulfide. The morphology of the nanoparticles was analysed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) was used for elemental analysis of nanoparticles. Fourier-transform infrared spectroscopy analysis (FTIR) was performed to assess the functional groups of the nanoparticles. Crystalline nature of nanoparticles was assessed using powder X-ray diffraction (XRD). Antibacterial studies of CdS nanoparticles were carried out on foodborne pathogens and cytotoxicity studies were carried out on Mus musculus skin melanoma (B16F10) and human epidermoid carcinoma (A431) cell lines. CdS nanoparticle showed more cytotoxic effect on cancer cells compared with standard 5-aminolevulinic acid (5-ALA). The Escherichia coli-synthesized CdS nanoparticles showed highest zone of inhibition in the ratio 4:1 of cadmium chloride and sodium sulfide on all tested bacterial strains. The nanoparticles were also tested for haemolytic activity on RBC cells, which exhibited lower cytotoxicity than sodium dodecyl sulphate which was used as positive control. The cytotoxicity of CdS nanoparticles assessed on A431 cells showed an inhibition of 81.53% at 100 μM concentration while the cytotoxicity assessed on B16F10 cells showed an inhibition of 75.71% at 200 μM concentration which was much efficient than 5-ALA which showed an inhibition of 31.95% at a concentration against B16F10 cells and 33.45% against A431 cells at a concentration of 1 mM. Cadmium sulfide nanoparticles were thus found to be highly toxic on cancer cells compare with standard anticancerous drug 5-ALA.

CdSe QD Biosynthesis in Yeast Using Tryptone-Enriched Media and Their Conjugation with a Peptide Hecate for Bacterial Detection and Killing

The physical and chemical synthesis methods of quantum dots (QDs) are generally unfavorable for biological applications. To overcome this limitation, the development of a novel “green” route to produce highly-fluorescent CdSe QDs constitutes a promising substitute approach. In the present work, CdSe QDs were biosynthesized in yeast Saccharomyces cerevisiae using a novel method, where we showed for the first time that the concentration of tryptone highly affects the synthesis process. The optimum concentration of tryptone was found to be 25 g/L for the highest yield. Different methods were used to optimize the QD extraction from yeast, and the best method was found to be by denaturation at 80 °C along with an ultrasound needle. Multiple physical characterizations including transmission electron microscopy (TEM), dynamic light scattering (DLS), energy-dispersive X-ray spectroscopy (EDX), and spectrophotometry confirmed the optical features size and shape distribution of the QDs. We showed that the novel conjugate of the CdSe QDs and a cell-penetrating peptide (hecate) can detect bacterial cells very efficiently under a fluorescent microscope. The conjugate also showed strong antibacterial activity against vancomycin-resistant Staphylococcus aureus (VRSA), methicillin-resistant Staphylococcus aureus (MRSA), and Escherichia coli, which may help us to cope with the problem of rising antibiotic resistance.

Efficacy of mycosynthesised AgNPs from Earliella scabrosa as an in vitro antibacterial and wound healing agent

The silver nanoparticles (AgNPs) with their unique chemical and physical properties are proving as a new therapeutical agent. In the present study, the AgNPs synthesised from an aqueous extract of a macrofungus, Earliella scabrosa, were characterised by field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDX), high-resolution transmission electron microscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and further evaluate for its in vitro antibacterial and wound healing efficacy. The mycosynthesised AgNPs exhibited the surface plasmon resonance peak at 410 nm with good stability over a period of a month. The FESEM and EDX analyses revealed the spherical-shaped AgNPs of an average size of 20 nm and the presence of elemental Ag, respectively. The XRD pattern showed the crystalline nature of AgNPs. The FTIR spectra confirmed the conversion of Ag+ ions to AgNPs due to reduction by biomolecules of macrofungus extract. The mycosynthesised AgNPs showed effective antibacterial activity against two Gram-positive bacteria, namely Bacillus subtilis and Staphylococcus aureus, and two Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa. The pathogens were highly sensitive to AgNPs, whereas less sensitive to AgNO3. The mycosynthesised AgNPs showed significant wound healing potential with 68.58% of wound closure.

Myconanotechnology in veterinary sector: Status quo and future perspectives

Nanotechnology is no longer a concept or a theory of the new world, it has turned into a new enabling technology over the years, with tremendous potential to revolutionize agriculture and livestock sector all over the globe. Moreover, nanotechnology provides new tools for molecular and cellular biology, biotechnology, veterinary physiology and reproduction, giving more promising solutions in both pathogen detection and therapy, engineering of agriculture, incredible results in animal and food systems and many more. Nanotechnology means manipulation, reduction and synthesis of materials at nano scale. Nanoparticles have distinct unique morphological characteristics which are quite different from their original bulk form. Recently, nanoparticles have been produced by industries for commercial applications having huge benefits. Since nanotechnology serves various fields of science and technology, the fabrication of nanoparticles using the biological route is becoming the need of the day. Biosynthesis of nanoparticles attracts the attentions of many researchers and industries to study microorganisms such as bacteria, fungi, algae and others as perfect biological factories for the fabrication of different nanoparticles. Among the different bionanofactories, the fungal system has emerged as an efficient most suitable system synthesizing metal nanoparticles by different mechanisms and for many reasons mentioned later. This review highlights the term “Myconanotechnology” in an attempt to direct more attention on fungi as a potential effective green approach in nanotechnology through conducting a SWOT analysis consisting of strengths, weaknesses, future opportunities of myconanosynthesis and probable constraints through eliciting questions for the possibility of using them in a large scale production.

L-Glutamine-assisted synthesis of ZnO oatmeal-like/silver composites as an electrochemical sensor for Pb2+ detection

We report a green synthesis of oatmeal ZnO/silver composites in the presence of L-glutamine as an electrochemical sensor for Pb²⁺ detection. The synthesis was performed via the direct reduction of Ag⁺ in the presence of L-glutamine in NaOH. X-ray diffraction indicated that the Ag⁺ was completely reduced to metallic Ag. The field emission scanning electron microscopy (FESEM) and energy dispersive X-ray results confirmed an oatmeal-like morphology of the ZnO with the presence of Ag. The FESEM images showed the effect of L-glutamine on the ZnO morphology. The EIS results confirmed a significant decrease in the charge transfer resistance of the modified glassy carbon electrode due to the presence of Ag. From the differential pulse voltammetry results, a linear working range for the concentration of Pb²⁺ between 5 and 6 nM with LOD of 0.078 nM (S/N = 3) was obtained. The sensitivity of the linear segment is 1.42 μA nM^-1 cm^-2. The presence of L-glutamine as the capping agent and stabilizer decreases the size of Ag nanoparticles and prevents the agglomeration of ZnO, respectively. Graphical abstract ᅟ.

Marine microorganisms for synthesis of metallic nanoparticles and their biomedical applications

Nanotechnology has become one of the most in demand technologies applied in different fields of science. Metallic nanoparticles synthesis using marine microorganisms has been received global attention due to their extensive applications in biomedical science. The use of marine microbes for metallic nanoparticles synthesis is eco-friendly, time saving, and inexpensive. An eco-friendly method is essential to minimize waste and protect environment. Recently, marine microorganisms are recognized an eco-friendly and efficient way to utilize as potential biofactories for synthesis of metallic nanoparticles. Here, we discuss and detail the possible uses of different marine microorganisms including bacteria, fungi and microalgae for metallic nanoparticle synthesis and those nanoparticles applications as antimicrobial and anticancer agents. In addition, different parameters that cause changes on nanoparticles shape and morphology are also highlighted.

Metallic nanoparticle synthesised by biological route: safer candidate for diverse applications

Biological synthesis of nanoparticles (NPs) involves greater prospect; however, a detailed review is required for ecofriendly, faster and stable NP formulation in large scale for different commercial applications. The present article highlighted recent updates on biological route of single and bimetallic NP synthesis wherein the chemical reducing agents are eliminated and biological entities are utilised to convert metal ions to NPs. Application of the biological reducing agents ranging from bacteria to fungi and even natural plant extracts have emerged as eco-friendly and cost-effective routes for the synthesis of metal nanomaterials. Potential applications of such NPs, a wide range of analytical techniques used for characterisation and factors influencing the synthesis of NPs are focused. Further, elucidation of the mechanisms associated with the NP formation using microorganisms, as well as plant-based materials are analysed which would be helpful for wide range of readers in the field of NP research for future selection and commercial implementation.

Recent progress of metal-graphene nanostructures in photocatalysis

Metal-graphene nanostructures (NSs) as photocatalysts, prepared using simple and scalable synthesis methods, are gaining heightened attention as novel materials for water treatment and environmental remediation applications. Graphene, the unique few layers sheet-like arrangement of sp2 hybridized carbon atoms, has an inimitable two-dimensional (2D) structure. The material is highly conductive, has high electron mobility and an extremely high surface area, and can be produced on a large scale at low cost. Accordingly, it has been considered as an essential base component for producing various metal-based NSs. In particular, metal-graphene NSs as photocatalysts have attracted considerable attention because of their special surface plasmon resonance (SPR) effect that can improve their performance for the removal of toxic dyes and other pollutants. This review summarizes the recent and advanced progress for the easy fabrication and design of graphene-based NSs as photocatalysts, as a novel tool, using a range of approaches, including green and biogenic approaches.