Green synthesis of copper nanoparticles by fruit extract of Ziziphus spina-christi (L.) Willd.: Application for adsorption of triphenylmethane dye and antibacterial assay

Plant biomass-based nanoparticles for remediation of contaminants from water ecosystems: Recent trends, challenges, and future perspectives

Green nanomaterials can mitigate ecological concerns by minimizing the impact of toxic contaminants on human and environmental health. Biosynthesis seems to be drawing unequivocal attention as the traditional methods of producing nanoparticles through chemical and physical routes are not sustainable. In order to utilize plant biomass, the current review outlines a sustainable method for producing non-toxic plant biomass-based nanoparticles and discusses their applications as well as recent trends involved in the remediation of contaminants, like organic/inorganic pollutants, pharmaceuticals, and radioactive pollutants from aquatic ecosystems. Plant biomass-based nanoparticles have been synthesized using various vegetal components, such as leaves, roots, flowers, stems, seeds, tuber, and bark, for applications in water purification. Phyto-mediated green nanoparticles are effectively utilized to treat contaminated water and reduce harmful substances. Effectiveness of adsorption has also been studied using variable parameters, e.g., pH, initial contaminant concentration, contact time, adsorbent dose, and temperature. Removal of environmental contaminants through reduction, photocatalytic degradation, and surface adsorption mechanisms, such as physical adsorption, precipitation, complexation, and ion exchange, primarily due to varying pH solutions and complex functional groups. In the case of organic pollutants, most of contaminants have been treated by catalytic reduction and photodegradation involving the formation of NaBH4, H2O2, or both. Whereas electrostatic interaction, metal complexation, H-bonding, π- π associations, and chelation along with reduction have played a major role in the adsorption of heavy metals, pharmaceuticals, radioactive and other inorganic pollutants. This review also highlights several challenges, like particle size, toxicity, stability, functional groups, cost of nanoparticle production, nanomaterial dynamics, and biological interactions, along with renewability and recycling of nanoparticles. Lastly, this review concluded that plant-biomass-based nanoparticles provide a sustainable, eco-friendly remediation method, utilizing the unique properties of nanomaterials and minimizing chemical synthesis risks.

Ecofriendly biosynthesis of copper nanoparticles from novel marine S. rhizophila species for enhanced antibiofilm, antimicrobial and antioxidant potential

Marine microorganisms offer a promising avenue for the eco-friendly synthesis of nanoparticles due to their unique biochemical capabilities and adaptability to various environments. This study focuses on exploring the potential of a marine bacterial species, Stenotrophomonas rhizophila BGNAK1, for the synthesis of biocompatible copper nanoparticles and their application for hindering biofilms formed by monomicrobial species. The study begins with the isolation of the novel marine S. rhizophila species from marine soil samples collected from the West coast region of Kerala, India. The isolated strain is identified through 16S rRNA gene sequencing and confirmed to be S. rhizophila species. Biosynthesis of copper nanoparticles using S. rhizophila results in the formation of nanoparticles with size of range 10-50 nm. The nanoparticles exhibit a face-centered cubic crystal structure of copper, as confirmed by X-Ray Diffraction analysis. Furthermore, the synthesized nanoparticles display significant antimicrobial activity against various pathogenic bacteria and yeast. The highest inhibitory activity was against Staphylococcus aureus with a zone of 27 ± 1.00 mm and the least activity was against Pseudomonas aeruginosa with a zone of 22 ± 0.50 mm. The zone of inhibition against Candida albicans was 16 ± 0.60 mm. The antibiofilm activity against biofilm-forming clinical pathogens was evidenced by the antibiofilm assay and SEM images. Additionally, the copper nanoparticles exhibit antioxidant activity, as evidenced by their scavenging ability against DPPH, hydroxyl, nitric oxide, and superoxide radicals, as well as their reducing power in the FRAP assay. The study highlights the potential of the marine bacterium S. rhizophila BGNAK1 for the eco-friendly biosynthesis of copper nanoparticles with diverse applications. Synthesized nanoparticles exhibit promising antibiofilm, antimicrobial, and antioxidant properties, suggesting their potential utility in various fields such as medicine, wastewater treatment, and environmental remediation.

Phytochemical Analysis of Silver Nanoparticles of Zingiber officinale and Evaluation for Its Antibacterial Property

Nonessential heavy metals are toxic to human health. In this study, mercury, a hazardous metal, was detected by colorimetric analysis using Zingiber (Z.) officinale. The eco-friendliness of this method was also emphasized. The ultraviolet (UV) spectrum is a broad peak observed at 200-250 nm in Z. officinale leaf extracts. The UV spectrum of green synthesized Z. officinale exhibited an absorption band of 286 nm, which confirms the nanoparticle (NP) synthesis. Fourier transform infrared (FTIR) analysis of the vibrational peak around 3307 cm-1 is assigned to ν(O-H) stretching that could possibly emanate from carbohydrates or phenolics. The peaks found around 2917 and 2849 cm-1 are ascribed to the -C-H stretch of the alkyl group, and the peak around 1625 cm-1 is due to the enolic β-diketones or -C = O stretch of carboxylic acids, while the corresponding -C-O stretch is observed around 1375 and 1029 cm-1. The assignment of peaks is similar. It is clear from the scanning electron microscope (SEM) image that the constituent parts were nonuniform, sphere-shaped, agglomerated, and of an average size of 30.9 nm. X-ray diffraction (XRD) analysis was used to determine the structural characteristics and crystalline nature of Z. officinale. The observed intensity peaks at 32.35°, 36.69°, 39.24°, 44.76°, 59.42°, and 67.35° are, respectively, of the Z. officinale diffraction 2θ values, which correspond to the standard database values. The synthesized copper NPs synthesized tested antibacterial properties against various strains of microorganisms, including Escherichia coli: 25 μg/mL 2.01 ± 0.11 and 100 μg/mL 5.37 ± 0.12, Staphylococcus (S.) aureus: 25 μg/mL 1.05 ± 0.71 and 100 μg/mL 11.43 ± 1.27, Streptococcus mutans: 25 μg/mL 02.01 ± 0.1 and 100 μg/mL 15.67 ± 0.17, and Enterococcus faecalis: 25 μg/mL 03.11 ± 0.7 and 100 μg/mL 18.32 ± 0.2. The short novelty of Z. officinale lies in its potential relevance to human health, as it has been found to possess bioactive compounds with various medicinal properties, such as antimicrobial, antioxidant, and anti-inflammatory activities, making it a promising natural resource for therapeutic applications.

Antifungal activity of copper oxide nanoparticles derived from Zizyphus spina leaf extract against Fusarium root rot disease in tomato plants

Incorporating green chemistry concepts into nanotechnology is an important focus area in nanoscience. The demand for green metal oxide nanoparticle production has grown in recent years. The beneficial effects of using nanoparticles in agriculture have already been established. Here, we highlight some potential antifungal properties of Zizyphus spina leaf extract-derived copper oxide nanoparticles (CuO-Zs-NPs), produced with a spherical shape and defined a 13-30 nm particle size. Three different dosages of CuO-Zs-NPs were utilized and showed promising antifungal efficacy in vitro and in vivo against the selected fungal strain of F. solani causes tomato root rot disease, which was molecularly identified with accession number (OP824846). In vivo  results indicated that, for all CuO-Zs-NPs concentrations, a significant reduction in Fusarium root rot disease occurred between 72.0 to 88.6% compared to 80.5% disease severity in the infected control. Although treatments with either the chemical fungicide (Kocide 2000) showed a better disease reduction and incidence with (18.33% and 6.67%) values, respectively, than CuO-Zs-NPs at conc. 50 mg/l, however CuO-Zs-NPs at 250 mg/l conc. showed the highest disease reduction (9.17 ± 2.89%) and lowest disease incidence (4.17 ± 3.80%). On the other hand, CuO-Zs-NPs at varied values elevated the beneficial effects of tomato seedling vigor at the initial stages and plant growth development compared to either treatment with the commercial fungicide or Trichoderma Biocide. Additionally, CuO-Zs-NPs treatments introduced beneficial results for tomato seedling development, with a significant increase in chlorophyll pigments and enzymatic activity for CuO-Zs-NPs treatments. Additionally, treatment with low concentrations of CuO-Zs-NPs led to a rise in the number of mature pollen grains compared to the immature ones.  however the data showed that CuO-Zs-NPs have a unique antifungal mechanism against F. solani, they  subsequently imply that CuO-Zs-NPs might be a useful environmentally friendly controlling agent for the Fusarium root rot disease that affects tomato plants.

Moringa oleifera seed based green synthesis of copper nanoparticles: Characterization, environmental remediation and antimicrobial activity

Textile dyes and heavy metals like hexavalent chromium [Cr(VI)] are considered major water pollutants. In addition, microbial contamination also seriously threatens potable water availability. The present study used Moringa oleifera seed aqueous extract to synthesize copper nanoparticles (MOS-CuNPs). MOS-CuNPs were characterized by various spectroscopy and microscopic techniques. MOS-CuNPs were shown to be effectual at removal of Cr(VI). The initial concentration of Cr(VI), contact time, pH, and temperature all impacted the removal of Cr(VI) by different concentrations of MOS-CuNPs. At low concentrations of MOS-CuNPs (0.3 mg/ml) pseudo-first order and high concentrations of MOS-CuNPs (0.4 and 0.5 mg/ml), pseudo-second order kinetics were obeyed. Thermodynamic analysis revealed that Cr(VI) was removed spontaneously, and the reaction was exothermic. In adsorption isotherm, equilibrium data followed Langmuir equation for Cr(VI) adsorption by MOS-CuNPs and maximum uptake capacity calculated was 38.6 mg/g. MOS-CuNPs efficiently removed cationic (rhodamine B, malachite green and methylene blue and) and anionic (congo red, titan yellow and methyl orange) dyes within 10 min of contact time. Further MOS-CuNPs showed antimicrobial activity against human pathogenic bacteria and fungi. Altogether, MOS-CuNPs could be used for environmental (water treatment) and biological applications.

Emerging micropollutants in aquatic ecosystems and nanotechnology-based removal alternatives: A review

There is a significant concern about the accessibility of uncontaminated and safe drinking water, a fundamental necessity for human beings. This concern is attributed to the toxic micropollutants from several emission sources, including industrial toxins, agricultural runoff, wastewater discharges, sewer overflows, landfills, algal blooms and microbiota. Emerging micropollutants (EMs) encompass a broad spectrum of compounds, including pharmaceutically active chemicals, personal care products, pesticides, industrial chemicals, steroid hormones, toxic nanomaterials, microplastics, heavy metals, and microorganisms. The pervasive and enduring nature of EMs has resulted in a detrimental impact on global urban water systems. Of late, these contaminants are receiving more attention due to their inherent potential to generate environmental toxicity and adverse health effects on humans and aquatic life. Although little progress has been made in discovering removal methodologies for EMs, a basic categorization procedure is required to identify and restrict the EMs to tackle the problem of these emerging contaminants. The present review paper provides a crude classification of EMs and their associated negative impact on aquatic life. Furthermore, it delves into various nanotechnology-based approaches as effective solutions to address the challenge of removing EMs from water, thereby ensuring potable drinking water. To conclude, this review paper addresses the challenges associated with the commercialization of nanomaterial, such as toxicity, high cost, inadequate government policies, and incompatibility with the present water purification system and recommends crucial directions for further research that should be pursued.

Biosynthesis of green CuO@C nanocomposite using Combretum indicum flower extract for organic dye removal: adsorption performance, modeling, and recyclability studies

Water contamination becomes one of the most high-priority environmental concerns, calling for the efficient treatment techniques. Bionanocomposites can be robust adsorbents, but the synthesis requires toxic chemicals or energy consuming and cause the secondary pollution. Green nanocomposites can be biogenically synthesized using the plant extract to end up with a critically safe strategy. Herein, we used the flower extract of Combretum indicum plant as a bio-based reductant and carbonaceous source for the green CuO@C nanocomposite. This green nanoadsorbent obtained a specific surface area of 17.33 m2/g, good crystallinity, and functional group-containing surface, i.e., -OH and -CONH-. We also conducted the optimization of parameters, i.e., concentration, CuO@C dose, pH, time, and temperature, and reached removal efficiencies towards malachite green (MG, 83.23%), Congo red (CR, 84.60%), brilliant blue (BB, 71.39%), and methylene blue (MB, 23.67%). The maximum adsorption capacities were found as ordered, MG (46.387 mg/g) > MB (23.154 mg/g) > BB (22.8 mg/g) > CR dye (11.063 mg/g). Through the intra-particle diffusion kinetic model, MG and BB adsorption endured a three-step process, while CR and MB adsorption was a two-step process. The recyclability of the green CuO@C nanocomposite was three cycles with 67.54% for the final cycle of BB removal. Moreover, the nanoadsorbent displayed a high stability, checked by X-ray diffraction, FT-IR analysis, EDX spectra, and SEM images. It is recommended that the green CuO@C nanocomposite biosynthesized using the Combretum indicum flower extract can be a good alternative for the dye treatment from wastewater.

A multifunctional recyclable adsorbent based on engineered MIL-125 (Ti) magnetic mesoporous composite for the effective removal of pathogens

The elimination of pathogenic bacteria from water sources is currently crucial for obtaining drinkable water. Therefore, the development of platforms with the ability to interact with pathogens and remove them is a potential future tool for medicine, food and water safety. In this work, we have grafted a layer of NH2-MIL-125 (Ti) on Fe3O4@SiO2 magnetic nanospheres for the removal of multiple pathogenic bacteria from water. The synthesized Fe3O4@SiO2@NH2-MIL-125 (Ti) nano adsorbent was characterized by FE-SEM, HR-TEM, FT-IR, XRD, BET surface analysis, magnetization tests, respectively, which illustrated its well-defined core-shell structure and magnetic behaviour. The prepared magnetic-MOF composite sorbent was attractive towards capturing a wide range of pathogens (S. typhimurium, S. aureus, E. coli, P. aeruginosa and K. pneumoniae) under experimental conditions. Influence factors such as adsorbent dosage, bacterial concentration, pH and incubation time were optimized for enhanced bacterial capture. The application of an external magnetic field removed Fe3O4@SiO2@NH2-MIL-125 (Ti) nano adsorbent from the solution along with sweeping the attached pathogenic bacteria. The non-specific removal efficiency of S. typhimurium for magnetic MOF composite was 96.58%, while it was only 46.81% with Fe3O4@SiO2 particles. For specific removal, 97.58% of S. typhimurium could be removed selectively from a mixture with monoclonal anti- Salmonella antibody conjugated magnetic MOF at a lower concentration of 1.0 mg/mL. The developed nano adsorbent may find great potential in microbiology applications and water remediation.

Biogenic nanoparticles from waste fruit peels: Synthesis, applications, challenges and future perspectives

Nanotechnology is a continually growing field with a wide range of applications from food science to biotechnology and nanobiotechnology. As the current world is grappling with non-biodegradable waste, considered more challenging and expensive to dispose of than biodegradable waste, new technologies are needed today more than ever. Modern technologies, especially nanotechnology, can transform biodegradable waste into products for human use. Researchers are exploring sustainable pathways for nanotechnology by utilizing biodegradable waste as a source for preparing nanomaterials. Over the past ten years, the biogenic production of metallic nanoparticles (NPs) has become a promising alternative technique to traditional NPs synthesis due to its simplicity, eco-friendliness, and biocompatibility in nature. Fruit and vegetable waste (after industrial processing) contain various bioactives (such as flavonoids, phenols, tannins, steroids, triterpenoids, glycosides, anthocyanins, carotenoids, ellagitannins, vitamin C, and essential oils) serving as reducing and capping agents for NP synthesis and they possess antibacterial, antioxidant, and anti-inflammatory properties. This review addresses various sources of biogenic NPs including their synthesis using fruit/vegetable waste, types of biogenic NPs, extraction processes and extracted biomaterials, the pharmacological functionality of NPs, industrial aspects, and future perspectives. In this manner, this review will cover the most recent research on the biogenic synthesis of NPs from fruit/vegetable peels to transform them into therapeutic nanomedicines.

Nanoremediation strategies to address environmental problems

A rapid rise in population, extensive anthropogenic activities including agricultural practices, up-scaled industrialization, massive deforestation, etc. are the leading causes of environmental degradation. Such uncontrolled and unabated practices have affected the quality of environment (water, soil, and air) synergistically by accumulating huge quantities of organic and inorganic pollutants in it. Environmental contamination is posing a threat to the existing life on the Earth, therefore, demands the development of sustainable environmental remediation approaches. The conventional physiochemical remediation approaches are laborious, expensive, and time-consuming. In this regard, nanoremediation has emerged as an innovative, rapid, economical, sustainable, and reliable approach to remediate various environmental pollutants and minimize or attenuate the risks associated with them. Owing to their unique properties such as high surface area to volume ratio, enhanced reactivity, tunable physical parameters, versatility, etc. nanoscale objects have gained attention in environmental clean-up practices. The current review highlights the role of nanoscale objects in the remediation of environmental contaminants to minimize their impact on human, plant, and animal health; and air, water, and soil quality. The aim of the review is to provide information about the applications of nanoscale objects in dye degradation, wastewater management, heavy metal and crude oil remediation, and mitigation of gaseous pollutants including greenhouse gases.

Green and Sustainable Membranes: A review

Membranes are ubiquitous tools for modern water treatment technology that critically eliminate hazardous materials such as organic, inorganic, heavy metals, and biomedical pollutants. Nowadays, nano-membranes are of particular interest for myriad applications such as water treatment, desalination, ion exchange, ion concentration control, and several kinds of biomedical applications. However, this state-of-the-art technology suffers from some drawbacks, e.g., toxicity and fouling of contaminants, which makes the synthesis of green and sustainable membranes indeed safety-threatening. Typically, sustainability, non-toxicity, performance optimization, and commercialization are concerns centered on manufacturing green synthesized membranes. Thus, critical issues related to toxicity, biosafety, and mechanistic aspects of green-synthesized nano-membranes have to be systematically and comprehensively reviewed and discussed. Herein we evaluate various aspects of green nano-membranes in terms of their synthesis, characterization, recycling, and commercialization aspects. Nanomaterials intended for nano-membrane development are classified in view of their chemistry/synthesis, advantages, and limitations. Indeed, attaining prominent adsorption capacity and selectivity in green-synthesized nano-membranes requires multi-objective optimization of a number of materials and manufacturing parameters. In addition, the efficacy and removal performance of green nano-membranes are analyzed theoretically and experimentally to provide researchers and manufacturers with a comprehensive image of green nano-membrane efficiency under real environmental conditions.

Biogenic Synthesis of Copper Nanoparticles: A Systematic Review of Their Features and Main Applications

Nanotechnology is an innovative field of study that has made significant progress due to its potential versatility and wide range of applications, precisely because of the development of metal nanoparticles such as copper. Nanoparticles are bodies composed of a nanometric cluster of atoms (1-100 nm). Biogenic alternatives have replaced their chemical synthesis due to their environmental friendliness, dependability, sustainability, and low energy demand. This ecofriendly option has medical, pharmaceutical, food, and agricultural applications. When compared to their chemical counterparts, using biological agents, such as micro-organisms and plant extracts, as reducing and stabilizing agents has shown viability and acceptance. Therefore, it is a feasible alternative for rapid synthesis and scaling-up processes. Several research articles on the biogenic synthesis of copper nanoparticles have been published over the past decade. Still, none provided an organized, comprehensive overview of their properties and potential applications. Thus, this systematic review aims to assess research articles published over the past decade regarding the antioxidant, antitumor, antimicrobial, dye removal, and catalytic activities of biogenically synthesized copper nanoparticles using the scientific methodology of big data analytics. Plant extract and micro-organisms (bacteria and fungi) are addressed as biological agents. We intend to assist the scientific community in comprehending and locating helpful information for future research or application development.

Synthesis of Green Copper Nanoparticles Using Medicinal Plant Krameria sp. Root Extract and Its Applications

Nanotechnology is one of the most dynamic research areas and the fastest-growing market. Developing eco-friendly products using available resources to acquire maximum production, better yield, and stability is a great challenge for nanotechnology. In this study, copper nanoparticles (CuNP) were synthesized via the green method using root extract of the medical plant Rhatany (Krameria sp.) as a reducing and capping agent and used to investigate the influence of microorganisms. The maximum production of CuNP was noted at 70 °C after 3 h of reaction time. The formation of nanoparticles was confirmed through UV-spectrophotometer, and the product showed an absorbance peak in the 422-430 nm range. The functional groups were observed using the FTIR technique, such as isocyanic acid attached to stabilize the nanoparticles. The spherical nature and average crystal sizes of the particle (6.16 nm) were determined using Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), and X-ray diffractometer (XRD) analysis. In tests with a few drug-resistant pathogenic bacteria and fungus species, CuNP showed encouraging antimicrobial efficacy. CuNP had a significant antioxidant capacity of 83.81% at 200 g/m^-1. Green synthesized CuNP are cost-effective and nontoxic and can be applied in agriculture, biomedical, and other fields.

Environmental sustainable: Biogenic copper oxide nanoparticles as nano-pesticides for investigating bioactivities against phytopathogens

Endocrine-disrupting chemicals (EDCs) are of interest in human physiopathology and have been extensively studied for their effects on the endocrine system. Research also focuses on the environmental impact of EDCs, including pesticides and engineered nanoparticles, and their toxicity to organisms. Green nanofabrication has surfaced as an environmentally conscious and sustainable approach to manufacture antimicrobial agents that can effectively manage phytopathogens. In this study, we examined the current understanding of the pathogenic activities of Azadirachta indica aqueous formulated green synthesized copper oxide nanoparticles (CuONPs) against phytopathogens. The CuONPs were analyzed and studied using a range of analytical and microscopic techniques, such as UV-visible spectrophotometer, Transmission electron microscope (TEM), Scanning electron microscope (SEM), X-ray diffraction (XRD) and Fourier transformed infrared spectroscopy (FTIR). The XRD spectral results revealed that the particles had a high crystal size, with an average size ranging from 40 to 100 nm. TEM and SEM images were utilized to verify the size and shape of the CuONPs, revealing that they varied between 20 and 80 nm. The existence of potential functional molecules involved in the reduction of the nanoparticles was confirmed by FTIR spectra and UV analysis. Biogenically synthesized CuONPs revealed significantly enhanced antimicrobial activities at 100 mg/L concentration in vitro by the biological method. The synthesized CuONPs at 500 μg/ml had a strong antioxidant activity which was examined through the free radicle scavenging method. Overall results of the green synthesized CuONPs have demonstrated significant synergetic effects in biological activities which can play a crucial impact in plant pathology against numerous phytopathogens.

Effective Adsorptive Removal of Coomassie Violet Dye from Aqueous Solutions Using Green Synthesized Zinc Hydroxide Nanoparticles Prepared from Calotropis gigantea Leaf Extract

The removal of color from dye wastewater is crucial, since dyes are extremely toxic and can cause cancer in a variety of life forms. Studies must be done to use cost-effective adsorbents for the removal of color from dye effluents to protect the environment. To our knowledge, virtually no research has been done to describe the possibility of using Calotropis gigantea leaf extract zinc hydroxide nanoparticles (CG-Zn(OH)2NPs) as an adsorbent for the decolorization of Coomassie violet (CV) from the aqueous emulsion, either in batch mode or continuously. In the present batch investigation, CV dye is removed from the synthetic aqueous phase using CG-Zn(OH)2NPs as an adsorbent. The synthesized nanoparticles were characterized using various instrumental techniques such as Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS) and Brunauer–Emmett–Teller (BET) surface area and pore volume, a particle size analyser, and zero-point charge. The decolorization efficacy of CV dye from an aqueous phase by the adsorbent was examined in batch mode by varying process parameters. The consequences of various experimental variables were optimized using response surface methodology (RSM) to achieve the maximum decolorization efficiency (90.74%) and equilibrium dye uptake, qe (35.12 mg g−1). The optimum pH, dye concentration, CG-Zn(OH)2NPs adsorbent dosage, and particle size were found to be 1.8, 225 mg L−1, 5 g L−1, and 78 μm, respectively for CV dye adsorption capacity at equilibrium. The adsorbent zero-point charge was found to be at pH 8.5. The Langmuir isotherm model provided a good representation of the equilibrium data in aqueous solutions, with a maximum monolayer adsorption capability (qmax) of 40.25 mg g−1 at 299 K. The dye adsorption rate follows a pseudo-second-order kinetic model at various dye concentrations, which indicated that the reaction is more chemisorption than physisorption. The negative values of ΔG and positive values of ΔH at different temperatures indicate that the adsorption process is spontaneous and endothermic, respectively. Reusability tests revealed that the prepared nanoparticles may be used for up to three runs, indicating that the novel CG-Zn(OH)2NPs seems to be a very promising adsorbent for the removal of Coomassie violet dye from wastewater.

Biofabrication of nanoparticles: sources, synthesis, and biomedical applications

Nanotechnology is an emerging applied science delivering crucial human interventions. Biogenic nanoparticles produced from natural sources have received attraction in recent times due to their positive attributes in both health and the environment. It is possible to produce nanoparticles using various microorganisms, plants, and marine sources. The bioreduction mechanism is generally employed for intra/extracellular synthesis of biogenic nanoparticles. Various biogenic sources have tremendous bioreduction potential, and capping agents impart stability. The obtained nanoparticles are typically characterized by conventional physical and chemical analysis techniques. Various process parameters, such as sources, ions, and temperature incubation periods, affect the production process. Unit operations such as filtration, purification, and drying play a role in the scale-up setup. Biogenic nanoparticles have extensive biomedical and healthcare applications. In this review, we summarized various sources, synthetic processes, and biomedical applications of metal nanoparticles produced by biogenic synthesis. We highlighted some of the patented inventions and their applications. The applications range from drug delivery to biosensing in various therapeutics and diagnostics. Although biogenic nanoparticles appear to be superior to their counterparts, the molecular mechanism degradation pathways, kinetics, and biodistribution are often missing in the published literature, and scientists should focus more on these aspects to move them from the bench side to clinics.

Metal nanoparticles produced by plants with antibacterial properties against Staphylococcus aureus

Staphylococcus aureus (S. aureus) is a pathogenic bacteria that causes a variety of potentially fatal infections. The emergence of antibiotic-resistant strains of S. aureus has made treatment even more difficult. In recent years, nanoparticles have been used as an alternative therapeutic agent for S. aureus infections. Among various methods for the synthesis of nanoparticles, the method utilizing plant extracts from different parts of a plant, such as root, stem, leaf, flower, seeds, etc. is gaining widespread usage. Phytochemicals present in plant extract are an inexpensive, eco-friendly, natural material that act as reducing and stabilization agent for the nanoparticle synthesis. The utilization of plant-fabricated nanoparticles against S. aureus is currently in trend. The current review discusses recent findings in the therapeutic application of phytofabricated metal-based nanoparticles against Staphylococcus aureus.

Recent insights into metallic nanoparticles in shelf-life extension of agrifoods: Properties, green synthesis, and major applications

Nanotechnology emerged as a revolutionary technology in various fields of applied sciences, such as biomedical engineering and food technology. The pivotal roles of nanocompounds have been explored in various fields, such as food protection, preservation, and enhancement of shelf life. In this sequence, metallic nanoparticles (MNPs) are proven to be useful in developing products with antimicrobial activity and subsequently improve the shelf life of agrifoods. The major application of MNPs has been observed in the packaging industry due to the combining ability of biopolymers with MNPs. In recent years, various metal nanoparticles have been explored to formulate various active food packaging materials. However, the method of production and the need for risk evaluation are still a topic of discussion among researchers around the world. In general, MNPs are synthesized by various chemical and physical means, which may pose variable health risks. To overcome such issues, the green synthesis of MNPs using microbial and plant extracts has been proposed by various researchers. In this review, we aimed at exploring the green synthesis of MNPs, their properties and characterization, various ways of utilizing MNPs to extend their shelf life, and, most importantly, the risk associated with these along with their quality and safety considerations.

Anthraquinone acted as a catalyst for the removal of triphenylmethane dye containing tertiary amino group: Characteristics and mechanism

Herein, we found that anthraquinone (AQ) acted as a catalyst for the rapid and effective removal of triphenylmethane dye containing tertiary amino group (TDAG). Results showed that AQ had an enhanced catalytic reactivity towards the removal of TDAG compared to hydro-quinone, which was further proved and explained using density functional theory (DFT) calculations. AQs could achieve a TDAG removal efficiency and rate of approximately 100% and 0.3583 min^-1, respectively, within 20 min. Quenching experiments and electron paramagnetic resonance (EPR) tests indicated that the superoxide radical (O₂^•-) generated through the catalytic reduction of an oxygen molecule (O₂) by AQ contributed to the effective removal of the TDAG. In addition, it was found that the electrophilic attack of the O₂^•- radical on the TDAG was the driving force for the dye degradation process. Decreasing the pH led to protonation of the substituted group of AG, which resulted in formation of an electron deficient center in the TDAG molecule (TDAG-EDC⁺) through delocalization of the π electron. Therefore, the possibility of the electrophilic attack for the dye by the negative O₂^•- radical was significantly enhanced. This study revealed that the H⁺ and the O₂^•- generated by the catalytic reduction of O₂ have synergistic effects that led to a significant increase in the dye removal rate and efficiency, which were higher than those obtained through persulfate oxidation.

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

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

Green Synthesis of Silver Nanoparticles from Diospyros villosa Extracts and Evaluation of Antioxidant, Antimicrobial and Anti-Quorum Sensing Potential

The biosynthesis of silver nanoparticles (AgNPs) from Diospyros villosa leaves and stem bark extracts is described. The stem bark AgNPs of D. villosa synthesized at 80 °C (S80) showed good scavenging activity with a lower IC50 value of 8.75 µg·mL−1 compared to ascorbic acid (9.58 µg·mL−1). The total phenol content of the S80 AgNPs was measured and found to be 10.22 ± 0.14 mg.g−1 gallic acid equivalence (GAE). Bacterial growth inhibition (% GI) and violacein inhibition (% VI) of 10.08% and 58.83%, respectively, was observed against C.subtsugae CV017 with leaf AgNPs synthesized at 80 °C (L80) at 80 μg·mL−1. Stem bark AgNPs synthesized at room temperature (SRT) also indicated % GI of 13.83% and % VI of 65.97% against C. subtsugae CV017 at 160 μg·mL−1. Leaf AgNPs of D. villosa synthesized at room temperature (LRT), showed % GI of 29.07% and % VI of 56.53%, respectively, against C. violaceum ATCC 12472 at 320 μg·mL−1. The L80 and SRT at 160 μg·mL−1 and LRT at 320 μg·mL−1 may be considered as potential QS inhibitors following their activity against C. subtsugae CV017 and C. violaceum ATCC 12472, respectively. Therefore, D. villosa represents a potential source of antioxidants as well as an anti-quorum sensing therapeutic candidate for the control of Gram-negative bacterial infections.

Biogenic Synthesis of Copper-Based Nanomaterials Using Plant Extracts and Their Applications: Current and Future Directions

Plants have been used for multiple purposes over thousands of years in various applications such as traditional Chinese medicine and Ayurveda. More recently, the special properties of phytochemicals within plant extracts have spurred researchers to pursue interdisciplinary studies uniting nanotechnology and biotechnology. Plant-mediated green synthesis of nanomaterials utilises the phytochemicals in plant extracts to produce nanomaterials. Previous publications have demonstrated that diverse types of nanomaterials can be produced from extracts of numerous plant components. This review aims to cover in detail the use of plant extracts to produce copper (Cu)-based nanomaterials, along with their robust applications. The working principles of plant-mediated Cu-based nanomaterials in biomedical and environmental applications are also addressed. In addition, it discusses potential biotechnological solutions and new applications and research directions concerning plant-mediated Cu-based nanomaterials that are yet to be discovered so as to realise the full potential of the plant-mediated green synthesis of nanomaterials in industrial-scale production and wider applications. This review provides readers with comprehensive information, guidance, and future research directions concerning: (1) plant extraction, (2) plant-mediated synthesis of Cu-based nanomaterials, (3) the applications of plant-mediated Cu-based nanomaterials in biomedical and environmental remediation, and (4) future research directions in this area.

Uranium and Thorium water decontamination via novel coated Cu-based nanoparticles; the role of chemistry and environmental implications

The removal of radioactive contaminants from aquifers is a matter of great concern. In this paper, coated copper-based nanoparticles (Cu-based NPs) were investigated as sorbent materials to remove uranium and thorium from low-level wastes, and especially from water, considering the influences of temperature, time, concentration, and pH. Cu-based NPs were derived through a hydrothermal synthesis from copper nitrate degradation in the presence of the bifunctional with COOH-terminated PEG, TEG as well as PEG 8000. The characterization was undertaken using XRD, TEM, TG/DTG, FTIR, and SEM-EDS. Isotherm models such as Langmuir and Freundlich were applied, while kinetic data were successfully reproduced by the pseudo-second-order equation and thermodynamic parameters were calculated. To investigate the removal mechanisms, UV-fluorescence and X-ray photoelectron spectroscopy were used. In the case of uranium, the predominant mechanism includes the formation of surface complexes, followed by extensive reduction (65%) of U(VI) to less soluble U(IV) while in the case of thorium, surface precipitation dominates. Copper nanoparticles exhibited significant U(VI) uptake capacity resulting in a decrease of the U-concentration below the acceptable limit of 30 μg/L and can be successfully applied in water treatment technology.

Green Derived Zinc Oxide (ZnO) for the Degradation of Dyes from Wastewater and Their Antimicrobial Activity: A Review

The quest for eco-friendly synthetic routes that can be used for the development of multifunctional materials, in particular for water treatment, has reinforced the use of plant extracts as replacement solvents in their use as reducing and capping agents during the synthesis of green derived materials. Amongst the various nanoparticles, Zinc Oxide (ZnO) has emerged as one of the preferred candidates for photocatalysis due to its optical properties. Moreover, ZnO has also been reported to possess antimicrobial properties against various bacterial strains such as E. coli and S. aureus. In this review, various types of pollutants including organic dyes and natural pollutants are discussed. The treatment methods that are used to purify wastewater with their limitations are highlighted. The distinguishing properties of ZnO are clearly outlined and defined, not to mention the performance of ZnO as a green derived photocatalyst and an antimicrobial agent, as well. Lastly, an overview is given of the challenges and possible further perspectives.

Recent advances on botanical biosynthesis of nanoparticles for catalytic, water treatment and agricultural applications: A review

Green synthesis of nanoparticles using plant extracts minimizes the usage of toxic chemicals or energy. Here, we concentrate on the green synthesis of nanoparticles using natural compounds from plant extracts and their applications in catalysis, water treatment and agriculture. Polyphenols, flavonoid, rutin, quercetin, myricetin, kaempferol, coumarin, and gallic acid in the plant extracts engage in the reduction and stabilization of green nanoparticles. Ten types of nanoparticles involving Ag, Au, Cu, Pt, CuO, ZnO, MgO, TiO₂, Fe₃O₄, and ZrO₂ with emphasis on their formation mechanism are illuminated. We find that green nanoparticles serve as excellent, and recyclable catalysts for reduction of nitrophenols and synthesis of organic compounds with high yields of 83-100% and at least 5 recycles. Many emerging pollutants such as synthetic dyes, antibiotics, heavy metal and oils are effectively mitigated (90-100%) using green nanoparticles. In agriculture, green nanoparticles efficiently immobilize toxic compounds in soil. They are also sufficient nanopesticides to kill harmful larvae, and nanoinsecticides against dangerous vectors of pathogens. As potential nanofertilizers and nanoagrochemicals, green nanoparticles will open a revolution in green agriculture for sustainable development.

Green synthesis of Ag2O nanoparticles using Punica granatum leaf extract for sulfamethoxazole antibiotic adsorption: characterization, experimental study, modeling, and DFT calculation

Silver oxide (Ag₂O) nanoparticles (NPs) were generated by synthesizing green leaf extract of Punica granatum, and afterwards they were used as adsorbent to remove the antibiotic additive sulfamethoxazole (SMX) from aqueous solutions. Prior of their use as adsorbent, the Ag₂O NPs were characterized by various methods such as X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), scanning electron microscopy/energy-dispersive X-ray (SEM-EDX), and transmission electron microscopy (TEM). The Ag₂O NPs were found to be spherically shaped and stabilized by the constituents of the extract. Further, at SMX antibiotic concentration of 100 mg L^-1, the Ag₂O NPs achieved almost complete removal of 98.93% within 90 min, and by using 0.8 g L^-1 of adsorbent dose at pH=4 and temperature T=308 K. In addition, the experimental data were well fitted with the theoretical Langmuir model indicating homogeneous adsorbed layer of the SMX antibiotic on the Ag₂O NPs surface. The maximum uptake capacity was 277.85 mg g^-1. A good agreement was also found between the kinetic adsorption data and the theoretical pseudo-second-order model. Regarding the thermodynamic adsorption aspects, the data revealed an endothermic nature and confirmed the feasibility and the spontaneity of the adsorption reaction. Furthermore, the regeneration study has shown that the Ag₂O NPs could be efficiently reused for up to five cycles. The geometric structures have been optimized and quantum chemical parameters were calculated for the SMX unprotonated (SMX^+/-) and protonated (SMX⁺) using density functional theory (DFT) calculation. The DFT results indicated that the unprotonated SMX^+/- reacts more favorably on the Ag₂O surface, as compared to the protonated SMX⁺. The SMX binding mechanism was predominantly controlled by the electrostatic attraction, hydrogen bond, hydrophobic, and π-π interactions. The overall data suggest that the Ag₂O NPs have promising potential for antibiotic removal from wastewater.

Plant Extract-Based Synthesis of Metallic Nanomaterials, Their Applications, and Safety Concerns

Nanotechnology has attracted the attention of researchers from different scientific fields because of the escalated properties of nanomaterials compared with the properties of macromolecules. Nanomaterials can be prepared through different approaches involving physical and chemical methods. The development of nanomaterials through plant-based green chemistry approaches is more advantageous than other methods from the perspectives of environmental safety, animal, and human health. The biomolecules and metabolites of plants act as reducing and capping agents for the synthesis of metallic green nanomaterials. Plant-based synthesis is a preferred approach as it is not only cost-effective, easy, safe, clean, and eco-friendly but also provides pure nanomaterials in high yield. Since nanomaterials have antimicrobial and antioxidant potential, green nanomaterials synthesized from plants can be used for a variety of biomedical and environmental remediation applications. Past studies have focused mainly on the overall biogenic synthesis of individual or combinations of metallic nanomaterials and their oxides from different biological sources, including microorganisms and biomolecules. Moreover, from the viewpoint of biomedical applications, the literature is mainly focusing on synthetic nanomaterials. Herein, we discuss the extraction of green molecules and recent developments in the synthesis of different plant-based metallic nanomaterials, including silver, gold, platinum, palladium, copper, zinc, iron, and carbon. Apart from the biomedical applications of metallic nanomaterials, including antimicrobial, anticancer, diagnostic, drug delivery, tissue engineering, and regenerative medicine applications, their environmental remediation potential is also discussed. Furthermore, safety concerns and safety regulations pertaining to green nanomaterials are also discussed. This article is protected by copyright. All rights reserved.

A Critical Review of the Antimicrobial and Antibiofilm Activities of Green-Synthesized Plant-Based Metallic Nanoparticles

Metallic nanoparticles (MNPs) produced by green synthesis using plant extracts have attracted huge interest in the scientific community due to their excellent antibacterial, antifungal and antibiofilm activities. To evaluate these pharmacological properties, several methods or protocols have been successfully developed and implemented. Although these protocols were mostly inspired by the guidelines from national and international regulatory bodies, they suffer from a glaring absence of standardization of the experimental conditions. This situation leads to a lack of reproducibility and comparability of data from different study settings. To minimize these problems, guidelines for the antimicrobial and antibiofilm evaluation of MNPs should be developed by specialists in the field. Being aware of the immensity of the workload and the efforts required to achieve this, we set out to undertake a meticulous literature review of different experimental protocols and laboratory conditions used for the antimicrobial and antibiofilm evaluation of MNPs that could be used as a basis for future guidelines. This review also brings together all the discrepancies resulting from the different experimental designs and emphasizes their impact on the biological activities as well as their interpretation. Finally, the paper proposes a general overview that requires extensive experimental investigations to set the stage for the future development of effective antimicrobial MNPs using green synthesis.

Evaluation of Zebrafish Toxicology and Biomedical Potential of Aeromonas hydrophila Mediated Copper Sulfide Nanoparticles

The present study deals with extracellular synthesis and characterization of copper sulfide (CuS) nanoparticles using Aeromonas hydrophila, and the biological applications of the synthesized CuS like antibacterial, anti-inflammatory, and antioxidant activity were reported. Further, the toxicological effects of the CuS were evaluated using zebrafish as an animal model. The primary step of the synthesis was carried out by adding the precursor copper sulfates to the culture supernatant of Aeromonas hydrophila. The UV-visible spectrophotometer was used to characterize the synthesized nanoparticles, and the peak was obtained at 307 nm through the reduction process. Fourier transform infrared spectroscopy (FTIR) was involved to find out the functional groups (carboxylic acid, alcohols, alkanes, and nitro compounds) associated with copper sulfide nanoparticles (CuS-NPs). Atomic force microscopy (AFM) was used to characterize the CuS topographically, and a scanning electron microscope (SEM) revealed about 200 nm sized CuS nanoparticles with agglomerated structures. Overall, the characterized nanoparticles can be considered as a potential candidate with therapeutic proficiencies as antibacterial, antioxidant, and anti-inflammatory mediator/agents.

Plant-derived nanotherapeutic systems to counter the overgrowing threat of resistant microbes and biofilms

Since antiquity, the survival of human civilization has always been threatened by the microbial infections. An alarming surge in the resistant microbial strains against the conventional drugs is quite evident in the preceding years. Furthermore, failure of currently available regimens of antibiotics has been highlighted by the emerging threat of biofilms in the community and hospital settings. Biofilms are complex dynamic composites rich in extracellular polysaccharides and DNA, supporting plethora of symbiotic microbial life forms, that can grow on both living and non-living surfaces. These enforced structures are impervious to the drugs and lead to spread of recurrent and non-treatable infections. There is a strong realization among the scientists and healthcare providers to work out alternative strategies to combat the issue of drug resistance and biofilms. Plants are a traditional but rich source of effective antimicrobials with wider spectrum due to presence of multiple constituents in perfect synergy. Other than the biocompatibility and the safety profile, these phytochemicals have been repeatedly proven to overcome the non-responsiveness of resistant microbes and films via multiple pathways such as blocking the efflux pumps, better penetration across the cell membranes or biofilms, and anti-adhesive properties. However, the unfavorable physicochemical attributes and stability issues of these phytochemicals have hampered their commercialization. These issues of the phytochemicals can be solved by designing suitably constructed nanoscaled structures. Nanosized systems can not only improve the physicochemical features of the encapsulated payloads but can also enhance their pharmacokinetic and therapeutic profile. This review encompasses why and how various types of phytochemicals and their nanosized preparations counter the microbial resistance and the biofouling. We believe that phytochemical in tandem with nanotechnological innovations can be employed to defeat the microbial resistance and biofilms. This review will help in better understanding of the challenges associated with developing such platforms and their future prospects.

Sustainable and green trends in using plant extracts for the synthesis of biogenic metal nanoparticles toward environmental and pharmaceutical advances: A review

Conventionally utilized physical and chemical routes for constructing nanoparticles are not eco-friendly. They are associated with many shortcomings like the requirement of specially designed equipment, templates, extremely high temperature, and pressure. Biosynthesis seems to be drawn unequivocal attention owing to its upsurge of applications in different fields like; energy, nutrition, pharmaceutical, and medicinal sciences. To harness the biological sources, the present review describes an environment-friendly route to generate biogenic nanoparticles from the natural plant extracts and the followed mechanisms for their synthesis, growth, and stabilization. The present review summarizes the recent trends involved in the photosynthesis of metallic nanoparticles and their effective use in controlling malaria, hepatitis, cancer, like various endemic diseases. Also, various characterization approaches, such as UV-visible spectrophotometry, Fourier transform infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy, are discussed here examine the properties of as-fabricated nanoparticles. Various plant parts like leaves, stems, barks, fruit, and flowers are rich in flavonoids, phenols, steroids, terpenoids, enzymes, and alkaloids, thereby playing an essential role in reducing metal ions that generate metallic nanoparticles. Herein, the uniqueness of phytofabricated nanoparticles along with their distinctive antibacterial, antioxidant, cytotoxic, and drug delivery properties are featured. Lastly, this work highlights the various challenges and future perspectives to further synthesize biogenic metal nanoparticles toward environmental and pharmaceutical advances in the coming years.

Copper: benefits and risks for poultry, livestock, and fish production

Protein production from animal origin should increase to meet the needs of a growing global population. This article presents an overview on copper (Cu) forms and their importance for animals' physiological functions. Moreover, it will focus on the current and promising nano-Cu applications in poultry, livestock, and fish production systems. Use of Cu as a feed additive directly or indirectly impacts the human food chain and may affect the safety and/or quality of food. Finally, the expected risks and hazards related to the use of nano-Cu that can affect animals, humans, and the environment are described. It is concluded that nano-Cu applications have the potential to provide an efficient solution for reducing the Cu amount in the poultry, livestock, and fish diets, which can help in reducing costs and environmental contamination and increasing animals' productivity. However, concerns over the safety of nano-Cu applications hamper their immediate implementation. Thus, rigorous risk assessments should be conducted to ensure the safety of animal-origin products in the case of supplementation animal diets with nano-copper.

Green synthesis, characterization and antimicrobial activities of Copper nanoparticles from the rhizomes extract of Picrorhiza kurroa

BACKGROUND

Green synthesized nanoparticles from the solvent extract of various plant parts show better biological activities as compared to parent solvent plant extract. Traditionally rhizomes of Picrorhiza kurroa are used to cure various diseases like diarrhea, fever, jaundice, eye infection, skin problems, asthma, arthritis, cancer, diabetes, gastrointestinal problems.

OBJECTIVES

Present study describes the synthesis of copper nanoparticles from a hydroethanolic extract of P. kurroa rhizomes (CuNPs-Pk) and their evaluation for antimicrobial activities against gram-negative, gram-positive bacterial, and fungal strains.

METHODS

The solution of copper sulfate and hydroethanolic extract of rhizomes of P. kurroa was mixed with help of a magnetic stirrer at 60°C temperature for 1 h. The blue color of CuSO₄.5H₂O changed to brownish-black colored copper nanoparticles within 10 minutes. These nanoparticles were centrifuged at 4000 rpm for 20 min, washed with ethanol, followed by deionized water, dried, and were characterized by Ultra violet-visible (UV-Vis) absorption spectra, Fourier transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (TEM). Different concentrations of hydroethanolic extract of Picrorhiza kurroa rhizomes (HEEPk), CuNPs-Pk and copper oxide nanoparticles (bare CuO) ranging from 100-400 ppm had been studied against selected bacterial and fungal strains by using the well plate diffusion method. Ciprofloxin and fluconazole were used as standard and Dimethyl sulfoxide (DMSO) as a control for selected strains.

RESULTS

The UV-Vis spectral studies confirmed the surface plasmon resonance of green-synthesized CuNPs-Pk. The particle size was found to be 275-285 nm. FTIR analysis of biosynthesis nanoparticles have been confirm the presence of various functional groups (flavonoids, glycosides, tannins, phenols). SEM and TEM of biosynthesized nanoparticles have predicted their spheric al shape and their size (20-40 nm) and These particles have shown effective antimicrobial activities against selected pathogenic organisms viz. Escherichia coli, Staphylococcus aureus, and Aspergillus niger than that of HEEPk and bare CuO.

CONCLUSIONS

The CuNPs-Pk show effective antimicrobial activities against bacterial and fungal pathogens as compared to HEEPk and bare CuO.

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

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

Plant-Extract-Mediated Synthesis of Metal Nanoparticles

Metal nanoparticles (MNPs) have been widely used in several fields including catalysis, bioengineering, photoelectricity, antibacterial, anticancer, and medical imaging due to their unique physical and chemical properties. In the traditional synthesis method of MNPs, toxic chemicals are generally used as reducing agents and stabilizing agents, which is fussy to operate and extremely environment unfriendly. Based on this, the development of an environment-friendly synthesis method of MNPs has recently attracted great attention. The use of plant extracts as reductants and stabilizers to synthesize MNPs has the advantages of low cost, environmental friendliness, sustainability, and ease of operation. Besides, the as-synthesized MNPs are nontoxic, more stable, and more uniform in size than the counterparts prepared by the traditional method. Thus, green preparation methods have become a research hotspot in the field of MNPs synthesis. In this review, recent advances in green synthesis of MNPs using plant extracts as reductants and stabilizers have been systematically summarized. In addition, the insights into the potential applications and future development for MNPs prepared by using plant extracts have been provided.

Bi-model cationic dye adsorption by native and surface-modified Trichoderma asperellum BPL MBT1 biomass: From fermentation waste to value-added biosorbent

In this study, we aimed to assess the possible reusability of native and surface-modified waste biomass of a novel ascomycetes fungi Trichoderma asperellum BPL MBT1 for the adsorption of triphenylmethane dyes. Spent biomass obtained from fermentation medium has been applied in the uptake of model cationic dyes viz., crystal violet and malachite green. Optimization of experimental parameters by batch mode studies revealed that dye adsorption is influenced by medium pH time, initial concentration of dyes, and adsorbent dosage. It was observed that pH 10 was optimum for cationic dye adsorption. Further, the adsorption process obeyed the bi-model (Langmuir-Freundlich model) isotherm and adhered to pseudo-second-order kinetics. The involvement of ion exchange as the dominant mechanism of dye adsorption was indicated by the mean free energy obtained from Dubinin-Radushkevich isotherm. Cellular morphology and the involved functional groups were studied by scanning electron microscopy and Fourier transform infrared spectroscopy that revealed the presence of carbon and oxygen containing groups on the surface. Maximum desorption efficiency was achieved using a 0.1 M solution of HCl and the stability of the biosorbent was confirmed through reusability analysis. Our results confirm the applicability of both native and surface-modified T. asperellum BPL MBT1 biomass as a potential biosorbent for the sustainable wastewater treatment and safe dye disposal.

Green Synthesis of Metallic Nanoparticles: Applications and Limitations

The past decade has witnessed a phenomenal rise in nanotechnology research due to its broad range of applications in diverse fields including food safety, transportation, sustainable energy, environmental science, catalysis, and medicine. The distinctive properties of nanomaterials (nano-sized particles in the range of 1 to 100 nm) make them uniquely suitable for such wide range of functions. The nanoparticles when manufactured using green synthesis methods are especially desirable being devoid of harsh operating conditions (high temperature and pressure), hazardous chemicals, or addition of external stabilizing or capping agents. Numerous plants and microorganisms are being experimented upon for an eco–friendly, cost–effective, and biologically safe process optimization. This review provides a comprehensive overview on the green synthesis of metallic NPs using plants and microorganisms, factors affecting the synthesis, and characterization of synthesized NPs. The potential applications of metal NPs in various sectors have also been highlighted along with the major challenges involved with respect to toxicity and translational research.

Green copper oxide nanoparticles for lead, nickel, and cadmium removal from contaminated water

Environmentally friendly copper oxide nanoparticles (CuO NPs) were prepared with a green synthesis route without using hazardous chemicals. Hence, the extracts of mint leaves and orange peels were utilized as reducing agents to synthesize CuO NPs-1 and CuO NPs-2, respectively. The synthesized CuO NPs nanoparticles were characterized using scanning electron microscopy (SEM), Energy Dispersive X-ray Analysis (EDX), BET surface area, Ultraviolet-Visible spectroscopy (UV-Vis), and Fourier Transform Infrared Spectroscopy (FT-IR). Various parameters of batch experiments were considered for the removal of Pb(II), Ni(II), and Cd(II) using the CuO NPs such as nanosorbent dose, contact time, pH, and initial metal concentration. The maximum uptake capacity (q_m) of both CuO NPs-1 and CuO NPs-2 followed the order of Pb(II) > Ni(II) > Cd(II). The optimum q_m of CuO NPs were 88.80, 54.90, and 15.60 mg g^-1 for Pb(II), Ni(II), and Cd(II), respectively and occurred at sorbent dose of 0.33 g L^-1 and pH of 6. Furthermore, isotherm and kinetic models were applied to fit the experimental data. Freundlich models (R² > 0.97) and pseudo-second-order model (R² > 0.96) were fitted well to the experimental data and the equilibrium of metal adsorption occurred within 60 min.

Applications of Fruit Polyphenols and Their Functionalized Nanoparticles Against Foodborne Bacteria: A Mini Review

The ingestion of contaminated water and food is known to cause food illness. Moreover, on assessing the patients suffering from foodborne disease has revealed the role of microbes in such diseases. Concerning which different methods have been developed for protecting food from microbes, the treatment of food with chemicals has been reported to exhibit an unwanted organoleptic effect while also affecting the nutritional value of food. Owing to these challenges, the demand for natural food preservatives has substantially increased. Therefore, the interest of researchers and food industries has shifted towards fruit polyphenols as potent inhibitors of foodborne bacteria. Recently, numerous fruit polyphenols have been acclaimed for their ability to avert toxin production and biofilm formation. Furthermore, various studies have recommended using fruit polyphenols solely or in combination with chemical disinfectants and food preservatives. Currently, different nanoparticles have been synthesized using fruit polyphenols to curb the growth of pathogenic microbes. Hence, this review intends to summarize the current knowledge about fruit polyphenols as antibacterial agents against foodborne pathogens. Additionally, the application of different fruit extracts in synthesizing functionalized nanoparticles has also been discussed.