Biogenic nanoparticles: copper, copper oxides, copper sulphides, complex copper nanostructures and their applications

Copper nanoparticles have been the focus of intensive study due to their potential applications in diverse fields including biomedicine, electronics, and optics. Copper-based nanostructured materials have been used in conductive films, lubrification, nanofluids, catalysis, and also as potent antimicrobial agent. The biogenic synthesis of metallic nanostructured nanoparticles is considered to be a green and eco-friendly technology since neither harmful chemicals nor high temperatures are involved in the process. The present review discusses the synthesis of copper nanostructured nanoparticles by bacteria, fungi, and plant extracts, showing that biogenic synthesis is an economically feasible, simple and non-polluting process. Applications for biogenic copper nanoparticles are also discussed.     

真菌介导纳米银生物合成的研究进展

纳米银(Silver nanoparticles,AgNPs)是指三维结构中至少有一维在1-100 nm范围内的金属银材料,在光学、电学、催化和医药等领域得到了广泛应用.利用真菌生物合成AgNPs相比于传统的化学、物理合成方法,具有反应条件温和、绿色低毒、环境友好等优势备受关注.综述了近年来合成AgNPs真菌种类的研究...     

Mechanistic aspects in the biogenic synthesis of extracellular metal nanoparticles by peptides,bacteria, fungi,and plants

Metal nanoparticles have been studied and applied in many areas including the biomedical, agricultural, electronic fields, etc. Several products of colloidal silver are already on the market. Research on new, eco-friendly and cheaper methods has been initiated. Biological production of metal nanoparticles has been studied by many researchers due to the convenience of the method that produces small particles stabilized by protein. However, the mechanism involved in this production has not yet been elucidated although hypothetical mechanisms have been proposed in the literature. Thus, this review discusses the various mechanisms provided for the biological synthesis of metal nanoparticles by peptides, bacteria, fungi, and plants. One thing that is clear is that the mechanistic aspects in some of the biological systems need more detailed studies.     

Green approach for nanoparticle biosynthesis by fungi: current trends and applications

In recent years, the green approach of nanoparticle synthesis by biological entities has been gaining great interest over various other physico-chemical methods, which are laden with many disadvantages. The important challenging issues in current nanotechnology include the development of reliable experimental techniques for the synthesis of nanoparticles of different compositions and sizes along with high monodispersity. Biological systems offer unique promising features to tailor nanomaterials with predefined properties. Fungi are the favorite choice of microorganisms due to the wide variety of advantages they offer over bacteria, yeast, actinomycetes, plants, and other physico-chemical techniques. The use of microorganisms for the deliberate synthesis of nanoparticles is a fairly new and exciting area of research with considerable potential for further development. This review describes an overview of the current green approaches for the synthesis of nanoparticles with particular emphasis on fungi, which are gaining worldwide popularity as nano-factories for the green synthesis of nanoparticles.     

Biogenic synthesis of metal nanoparticles from actinomycetes: biomedical applications and cytotoxicity

Biogenic synthesis of metal nanoparticles has been well proved by using bacteria, fungi, algae, actinomycetes, plants, etc. Among the different microorganisms used for the synthesis of metal nanoparticles, actinomycetes are less known. Although, there are reports, which have shown that actinomycetes are efficient candidates for the production of metal nanoparticles both intracellularly and extracellularly. The nanoparticles synthesized by the members of actinomycetes present good polydispersity and stability and possess significant biocidal activities against various pathogens. The present review focuses on biological synthesis of metal nanoparticles and their application in medicine. In addition, the toxicity of these biogenic metal nanoparticles to human beings and environment has also been discussed.     

Biotemplates in the green synthesis of silver nanoparticles

This article recapitulates the scientific advancement towards the greener synthesis of silver nanoparticles. Applications of noble metals have increased throughout human civilization, and the uses for nano-sized particles are even more remarkable. “Green” nanoparticle synthesis has been achieved using environmentally acceptable solvent systems and eco-friendly reducing and capping agents. Numerous microorganisms and plant extracts have been applied to synthesize inorganic nanostructures either intracellularly or extracellularly. The use of nanoparticles derived from noble metals has spread to many areas including jewelery, medical fields, electronics, water treatment and sport utilities, thus improving the longevity and comfort in human life. The application of nanoparticles as delivery vehicles for bactericidal agents represents a new paradigm in the design of antibacterial therapeutics. Orientation, size and physical properties of nanoparticles influences the performance and reproducibility of a potential device, thus making the synthesis and assembly of shape- and size-controlled nanocrystals an essential component for any practical application. This need has motivated researchers to explore different synthesis protocols.     

Mycoendophytes as efficient synthesizers of bionanoparticles: nanoantimicrobials,mechanism, and cytotoxicity

Mycoendophytes are the fungi that occur inside the plant tissues without exerting any negative impact on the host plant. They are most frequently isolated endophytes from the leaf, stem, and root tissues of various plants. Among all fungi, the mycoendophytes as biosynthesizer of noble metal nanoparticles (NPs) are less known. However, some reports showing efficient synthesis of metal nanoparticles, mainly silver nanoparticles and its remarkable antimicrobial activity against bacterial and fungal pathogens of humans and plants. The nanoparticles synthesized from mycoendophytes present stability, polydispersity, and biocompatibility. These are non-toxic to humans and environment, can be gained in an easy and cost-effective manner, have wide applicability and could be explored as promising candidates for a variety of biomedical, pharmaceutical, and agricultural applications. Mycogenic silver nanoparticles have also demonstrated cytotoxic activity against cancer cell lines and may prove to be a promising anticancer agent. The present review focuses on the biological synthesis of metal nanoparticles from mycoendophytes and their application in medicine. In addition, different mechanisms of biosynthesis and activity of nanoparticles on microbial cells, as well as toxicity of these mycogenic metal nanoparticles, have also been discussed.     

微生物介导的金纳米颗粒合成

金纳米颗粒凭借其独特的光学和电化学特性,广泛应用于信息存储、化学传感、医学成像、药物传输以及生物标记等领域。近年来,生物法合成金纳米颗粒因其环境友好、绿色低毒等特点引起研究者的广泛关注。研究表明,多种微生物包括细菌、放线菌、真菌和病毒等均具有合成金纳米颗粒的能力。本文综述了微生物介导合成金纳米颗粒的特性、机制及应用,并对未来发展趋势进行了展望。     

Bioactivity,mechanism of action,and cytotoxicity of copper-based nanoparticles: A review

Nanotechnology is an emerging branch of science, which has potential to solve many problems in different fields. The union of nanotechnology with other fields of sciences including physics, chemistry, and biology has brought the concept of synthesis of nanoparticles from their respective metals. Till date, many types of nanoparticles have been synthesized and being used in different fields for various applications. Moreover, copper nanoparticles attract biologists because of their significant and broad-spectrum bioactivity. Due to the large surface area to volume ratio, copper nanoparticles have been used as potential antimicrobial agent in many biomedical applications. But the excess use of any metal nanoparticles increase the chance of toxicity to humans, other living beings, and environment. In this article, we have critically reviewed the bioactivities and cytotoxicity of copper nanoparticles. We have also focused on possible mechanism involved in its interaction with microbes.     

Metallic silver nanoparticle: a therapeutic agent in combination with antifungal drug against human fungal pathogen

Silver nanoparticles (Ag-NPs) are known to have inhibitory and fungicidal effects. Resistance against fungal infection has emerged as a major health problem in recent years, which needs great and immediate concern. Here, we report the extracellular biological synthesis of silver nanoparticles through a simple green route approach using a marine mangrove (Rhizophora mucronata) and silver nitrate. Aqueous extract of marine mangrove helped in reduction and was used as capping agent in biological synthesis. Nanoparticles were characterized using microscopy and spectroscopy techniques such as HRTEM, UV–Vis absorption spectroscopy and FTIR spectroscopy. X-ray diffraction analysis showed that the nanoparticles had face centered cubic structure with crystalline nature. FTIR spectroscopy showed the presence of different functional groups, such as hydroxyl and carbonyl, involved in the synthesis of nanoparticles. The antifungal activity of fluconazole and itraconazole was enhanced against the tested pathogenic fungi in the presence of Ag-NP and confirmed from increase in fold area of inhibition. This environmentally friendly method of biological synthesis can be easily integrated for various medical applications.     

Microorganisms as efficient biosystem for the synthesis of metal nanoparticles: current scenario and future possibilities

Nanoparticles, the elementary structures of nanotechnology, are important materials for fundamental studies and variety of applications. The different sizes and shapes of these materials exhibit unique physical and chemical properties than their bulk materials. There is a great interest in obtaining well-dispersed, ultrafine, and uniform nanoparticles to delineate and utilize their distinct properties. Nanoparticle synthesis can be achieved through a wide range of materials utilizing a number of methods including physical, chemical, and biological processes with various precursors from liquids and solids. There is a growing need to prepare environmentally friendly nanoparticles that do not produce toxic wastes in their process synthesis protocol. This kind of synthesis can be achieved by green environment benign processes, which happen to be mostly of a biological nature. Microorganisms are one of the most attractive and simple sources for the synthesis of different types of nanoparticles. This review is an attempt to provide the up-to-date information on current status of nanoparticle synthesis by different types of microorganisms such as fungi, yeast, bacteria, cyanobacteria, actinomycete, and algae. The probable biosynthesis mechanism and conditions for size/shape control are described. Various applications of microbially synthesized nanoparticles are summarized. They include antibacterial, antifungal, anticancer, larvicidal, medical imaging, biosensor, and catalytic applications. Finally, limitations and future prospects for specific research are discussed.     

Colloidal Synthesis of Plasmonic Metallic Nanoparticles

Solutions of Ag and Au nanoparticles are strongly colored because of localized surface plasmon resonance in the UV/visible spectral region. The optical properties of these nanoparticles may be tuned to suit the needs of the application. This article summarizes our work in recent years on the solution synthesis of nanoparticles with tunable optical properties. The systems of interest include zero-dimensional bimetallic Ag–Au nanoparticles with different structures, one-, two-, and three-dimensional anisotropic monometallic Ag or Au nanoparticles. All of these nanosystems were prepared from colloidal synthesis through simple changes in the synthesis conditions. This is a demonstration of the versatility of colloidal synthesis as a convenient scalable technique for tuning the properties of metallic nanoparticles. Zhang, Tan, and Xie contributed equally to this article     

Potential of plant as a biological factory to synthesize gold and silver nanoparticles and their applications

Green synthesis of metallic nanoparticles has become a promising field of research in recent years. Syntheses of gold and silver nanoparticles by various chemical and physical methods as well as the biosynthetic approach mediated by numerous microorganisms have been actively researched. A more scalable and economic route to produce these metallic nanoparticles would be through the plant-mediated synthetic approach. Owing to the biodiversity of plant biomasses, the mechanism by which bioconstituents of plants have contributed to the synthetic process is yet to be fully understood. Nevertheless, the feasibility of controlling the shape and size of nanoparticles by varying the reaction conditions has been demonstrated in many studies. This paper provides an overview of the plant-mediated syntheses of gold and silver nanoparticles, possible compounds and mechanisms that might be responsible for the bioreduction process as well as the potential applications of biosynthesized nanoparticles in different fields. The challenges and limitations of this plant-mediated biosynthetic approach are also discussed.     

Actinomycetes‐mediated biogenic synthesis of metal and metal oxide nanoparticles: progress and challenges

Actinomycetes‐mediated biogenic synthesis of metal nanoparticles and their antimicrobial activities are well documented. Actinomycetes facilitate both intracellular and extracellular metal nanoparticles synthesis and are efficient candidates for the production of polydispersed, stable and ultra‐small size metal nanoparticles. Secondary metabolites and new chemical entities derived from Actinomycetes have not been extensively studied for the synthesis of metal/metal oxide nanoparticles. The present review focuses on biogenic synthesis of metal nanoparticles from Actinomycetes and the scope for exploring Actinomycetes‐derived compounds (enzymes, organics acids and bioactive compounds) as metal and metal oxide reducing agents for the synthesis of desired nanoparticles. This review also focuses on challenges faced in the applications of nanoparticles and the methods to synthesize biogenic metal nanoparticles with desired physiochemical properties such as ultra‐small size, large surface to mass ratio, high reactivity etc. Methods to evade their toxicity and unique interactions with biological systems to improve their chance as an alternative therapeutic agent in medical and pharmaceutical industry are also discussed.     

微生物合成纳米银的一般方法及产物性质鉴定与生产应用

纳米银具有独特的理化性质,在化学、医药等领域应用广泛,但使用化学和物理法生产纳米银毒性较强且污染严重,因此,微生物法成为了一种可供替代的绿色生产技术。近年来,微生物法合成纳米银的报道逐渐增多,对其反应条件和产物性质的研究趋于成熟,纳米银也开始与多个应用领域相结合。归纳现有微生物合成方法的规律,阐述产物的性质及应用,比较其与传统材料的优势与不足,将有助于推动微生物与纳米技术的结合与进步。基于国内外学者的报道和本课题组所开展的相关研究,本文对微生物法合成纳米银的一般检验手段和功能鉴定方法进行综述,并就纳米银的应用展开设想与讨论,以期为微生物法合成纳米银的深入研究和优化改进提供参考。     

综述——新型纳米生物材料的研发：磁性纳米材料：化学合成、功能化与生物医学应用

磁性纳米材料,由于其独特的磁学性能、小尺寸效应,被广泛应用于生物医学领域．本文总结了磁性纳米材料的化学设计与合成、表面功能化方法,及其在核磁共振成像、磁控治疗、磁热疗和生物分离等生物医学领域的应用进展．     

Detection and identification of fungal species by electronic nose technology: A systematic review

A rapid and effective identification of fungal species is essential for numerous applications, and electronic nose systems are being proposed as suitable alternatives to currently available fungi identification techniques. Hence, the present review aims to unveil all published information concerning fungi identification by electronic nose systems.A systematic review of the literature was conducted according to the PRISMA guidelines. A total of 16 articles met the inclusion criteria and were included in the analysis. The results of the reviewed studies demonstrated that effective detection of fungi was possible through sensor-based electronic nose systems, which may actually function as a mycotoxin screening tool for several applications.The obtained results suggest that the sensor-based electronic nose systems may not only screen different fungi genera, but also identify the associated species. This technology has already been experimented in several fields, from food industry to clinical practice.By summarizing these results, the present review may accelerate the standardization of electronic noses in fungi detection and discrimination, allowing a faster and more efficient screening of samples.     

Synthesis of silver nanoparticles using haloarchaeal isolate Halococcus salifodinae BK3

Numerous bacteria, fungi, yeasts and viruses have been exploited for biosynthesis of highly structured metal sulfide and metallic nanoparticles. Haloarchaea (salt-loving archaea) of the third domain of life Archaea, on the other hand have not yet been explored for nanoparticle synthesis. In this study, we report the intracellular synthesis of stable, mostly spherical silver nanoparticles (AgNPs) by the haloarchaeal isolate Halococcus salifodinae BK₃. The culture on adaptation to silver nitrate exhibited growth kinetics similar to that of the control. NADH-dependent nitrate reductase was involved in silver tolerance, reduction, synthesis of AgNPs, and exhibited metal-dependent increase in enzyme activity. The AgNPs preparation was characterized using UV–visible spectroscopy, XRD, TEM and EDAX. The XRD analysis of the nanoparticles showed the characteristic Bragg peaks of face-centered cubic silver with crystallite domain size of 22 and 12 nm for AgNPs synthesized in NTYE and halophilic nitrate broth (HNB), respectively. The average particle size obtained from TEM analysis was 50.3 and 12 nm for AgNPs synthesized in NTYE and HNB, respectively. This is the first report on the synthesis of silver nanoparticles by haloarchaea.     

Synthesis,characterization, and antibacterial properties of silver nanoparticles-graphene and graphene oxide composites

In the field of nanotechnology, silver nanoparticles have been considered a promising antibacterial material for a century. The potential applications of graphene-based materials are increasingly recognized for their special physico-chemical and biological properties. In particular, graphene and graphene oxide as the foundation of nanocomposites have garnered much interest among researchers in many fields. In this review, we concentrate on different aspects of silver nanoparticle composites with graphene and graphene oxide, focusing on their synthesis methods, special characteristics, and antibacterial properties; we also briefly discuss limitations and future research.     

Gold and silver nanoparticles: Green synthesis,microbes, mechanism,factors, plant disease management and environmental risks

Metal nanoparticles were being used in different processes of developmental sectors like agriculture, industry, medical and pharmaceuticals. Nano-biotechnology along with sustainable organic chemistry has immense potential to reproduce innovative and key components of the systems to support surrounding environment, human health, and industry sustainably. Different unconventional methods were being used in green chemistry to synthesize gold and silver nanoparticles from various microbes. So, we reviewed different biological processes for green synthesis of metal nanoparticles. We also studied the mechanism of the synthesis process and procedures to characterize them. Some metallic nanoparticles have shown their potential to act as antimicrobial agent against plant pathogens. Here, we outlined green nanoparticles synthesized from microbes and highlighted their role against plant disease management.