Bio-approach: Ureolytic bacteria mediated synthesis of ZnO nanocrystals on cotton fabric and evaluation of their antibacterial properties

Bio-valorization of Tagetes floral waste extract in fabrication of self-healing Schiff-base nanocomposite hydrogels for colon cancer remedy

The drastic boom in floriculture and social events in religious and recreational places has inevitably led to generation of tremendous floral waste across the globe. Marigold (Tagetes erecta) is one of the most common loose flowers offered for the same. Generally discarded, these Tagetes floral wastes could be valorized for biogenic syntheses. In this study, we have utilized the floral extract towards green synthesis of nano ZnO, the formation of which was affirmed from different analytical techniques. Bionanocomposite Schiff-base hydrogel composed of chitosan and dialdehyde pectin was fabricated by the facile strategy of in situ polymer cross-linking, and the ZnO nanoparticles were embedded in the hydrogel matrix. The hydrogel exhibited remarkable self-healing ability. The antioxidant and anti-inflammatory activities were enhanced owing to nano ZnO. Furthermore, it was hemocompatible and biodegradable. A controlled release drug profile for 5-fluorouracil from the hydrogel was accomplished in the colorectum. The exposure of the drug-loaded nanocomposite hydrogel demonstrated improved anticancer effects in HT-29 colon cancer cells. The findings of this study altogether put forth the successful biovalorization of Tagetes floral waste extract for colon cancer remedy.

Recent advances in the synthesis, characterization and biomedical applications of zinc oxide nanoparticles

Zinc oxide nanoparticles (ZnONPs) have become the widely used metal oxide nanoparticles and drawn the interest of global researchers due to their biocompatibility, low toxicity, sustainability and cost-effective properties. Due to their unique optical and chemical properties, it emerges as a potential candidate in the fields of optical, electrical, food packaging and biomedical applications. Biological methods using green or natural routes are more environmentally friendly, simple and less use of hazardous techniques than chemical and/or physical methods in the long run. In addition, ZnONPs are less harmful and biodegradable while having the ability to greatly boost pharmacophore bioactivity. They play an important role in cell apoptosis because they enhance the generation of reactive oxygen species (ROS) and release zinc ions (Zn2+), causing cell death. Furthermore, these ZnONPs work well in conjunction with components that aid in wound healing and biosensing to track minute amounts of biomarkers connected to a variety of illnesses. Overall, the present review discusses the synthesis and most recent developments of ZnONPs from green sources including leaves, stems, bark, roots, fruits, flowers, bacteria, fungi, algae and protein, as well as put lights on their biomedical applications such as antimicrobial, antioxidant, antidiabetic, anticancer, anti-inflammatory, antiviral, wound healing, and drug delivery, and modes of action associated. Finally, the future perspectives of biosynthesized ZnONPs in research and biomedical applications are discussed.

Zinc oxide nanoparticles prepared through microbial mediated synthesis for therapeutic applications: a possible alternative for plants

Zinc oxide nanoparticles (ZnO-NPs) synthesized through biogenic methods have gained significant attention due to their unique properties and potential applications in various biological fields. Unlike chemical and physical approaches that may lead to environmental pollution, biogenic synthesis offers a greener alternative, minimizing hazardous environmental impacts. During biogenic synthesis, metabolites present in the biotic sources (like plants and microbes) serve as bio-reductants and bio-stabilizers. Among the biotic sources, microbes have emerged as a promising option for ZnO-NPs synthesis due to their numerous advantages, such as being environmentally friendly, non-toxic, biodegradable, and biocompatible. Various microbes like bacteria, actinomycetes, fungi, and yeast can be employed to synthesize ZnO-NPs. The synthesis can occur either intracellularly, within the microbial cells, or extracellularly, using proteins, enzymes, and other biomolecules secreted by the microbes. The main key advantage of biogenic synthesis is manipulating the reaction conditions to optimize the preferred shape and size of the ZnO-NPs. This control over the synthesis process allows tailoring the NPs for specific applications in various fields, including medicine, agriculture, environmental remediation, and more. Some potential applications include drug delivery systems, antibacterial agents, bioimaging, biosensors, and nano-fertilizers for improved crop growth. While the green synthesis of ZnO-NPs through microbes offers numerous benefits, it is essential to assess their toxicological effects, a critical aspect that requires thorough investigation to ensure their safe use in various applications. Overall, the presented review highlights the mechanism of biogenic synthesis of ZnO-NPs using microbes and their exploration of potential applications while emphasizing the importance of studying their toxicological effects to ensure a viable and environmentally friendly green strategy.

Biogenic Zinc Oxide Nanoparticles and Their Biomedical Applications: A Review

Nanotechnology has inscribed novel perception into the material science and one of the most extensively used nanomaterials is Zinc oxide nanoparticles (ZnO NPs) with healthcare and biomedical applications. Because of its outstanding biocompatibility, low toxicity, and low cost, ZnO NPs have become one of the most prominent metal oxide NPs in biological applications. This review highlights the different aspects of ZnO NPs, like their green synthesis as a substitute of conventional route due to avoidance of threat of hazardous, costly precursors and subsequent mostly therapeutic applications. Due to their wide bandwidth and high excitation binding energy, ZnO NPs have undergone extensive research. In addition to their potential applications as antibiotics, antioxidants, anti-diabetics, and cytotoxic agents, ZnO NPs also hold a promising future as an antiviral treatment for SARS-CoV-2. Zn has antiviral properties and may be effective against a variety of respiratory virus species, particularly SARS-CoV-2. This review includes a variety of topics, including the virus's structural properties, an overview of infection mechanism, and current COVID-19 treatments. Nanotechnology-based techniques for the prevention, diagnosis, and treatment of COVID-19 are also discussed in this review.

Potential use of bio functionalized nanoparticles to attenuate triple negative breast cancer (MDA-MB-231 cells)

This study showed that bio-functional silver nanoparticles (AgNPs) and zinc oxide nanoparticles (ZnONPs) were synthesized in aqueous extracts of Gymnema sylvestre leaves and tested for toxicity assessment against triple-negative breast cancer cells (TNBC). Biofunctional nanoparticle (NPs) samples were characterized using UV-Vis spectroscopy, FT-IR, XRD, SEM, and TEM. The results showed that the phytofabrication of AgNPs resulted in a dark brown, UV-vis maximum absorbance peak at 413 nm. The AgNPs were crystalline and spherical, with sizes ranging from 20 to 60 nm, as confirmed by the XRD pattern and TEM images. Another phytofabrication of ZnONPs exhibited a white precipitate corresponding to a UV-Vis maximum absorption peak at 377 nm and a fine micro flower morphology with a particle-sized tribution between 100 and 200 nm. In addition, FT-IR spectra showed that bioorganic compounds are associated with NPs that respond to reduced Ag⁺ ions and AgNPs tabilizers. Invitro cytotoxicity studies revealed the potent anti-cancer effects of phytofabricated AgNPs and ZnONPs on TNBC cells. Furthermore, the AO/EB double staining assay results proved that apoptotic cells are distinguished by greenish-yellow fluorescence of the cell nuclei with IC₅₀ concentrations of 44 ± 0.8 µg/mL for AgNPs and 26.2 ± 0.5 µg/mL for ZnONPs, respectively. Based on our results, we expect that the anticancer function of the biofunctional NPs is due to the apoptotic activation of TNBC cells by increased ROS. Therefore, the presented study demonstrated that biofunctional AgNPs and ZnONPs have excellent prospects for the anti-cancer activity that can be used in pharmaceutical and medical fields.

An eco-friendly approach on green synthesis, bio-engineering applications, and future outlook of ZnO nanomaterial: A critical review

Synthesizing ZnO nanostructures ranging from 1 nm to 4 nm confines the electron cloud and exhibits a quantum effect generally called as quantum confinement effect attracting many researchers in the field of electronics and optics. ZnO nanostructures are used in medical applications to formulate antioxidant, antibacterial, antifungal, anti-inflammatory, wound healing, and anti-diabetic medications. This work is a comprehensive study of green synthesis of ZnO nanomaterials using different biological sources and highlights different processes able to produce nanostructures including nanowires, nanorods, nanotubes and other nano shapes of ZnO nanostructures. Different properties of ZnO nanostructures and their targeted bioengineering applications are also described. The strategies and challenges of the eco-friendly approach to enhance the application span of ZnO nanomaterials are also summarized, with future prospects for greener design of ZnO nanomaterials are also suggested.

Nanotechnology - A new frontier of nano-farming in agricultural and food production and its development

The potential of nanotechnology for the development of sustainable agriculture has been promising. The initiatives to meet the rising food needs of the rapidly growing world population are mainly powered by sustainable agriculture. Nanoparticles are used in agriculture due to their distinct physicochemical characteristics. The interaction of nanomaterials with soil components is strongly determined in terms of soil quality and plant growth. Numerous research has been carried out to investigate how nanoparticles affect the growth and development of plants. Nanotechnology has been applied to improve the quality and reduce post-harvest loss of agricultural products by extending their shelf life, particularly for fruits and vegetables. This review assesses the latest literature on nanotechnology, which is used as a nano-biofertilizer as seen in the agricultural field for high productivity and better growth of plants, an important source of balanced nutrition for the crop, seed germination, and quality enrichment. Additionally, post-harvest food processing and packaging can benefit greatly from the use of nanotechnology to cut down on food waste and contamination. It also critically discusses the mechanisms involved in nanoparticle absorption and translocation within the plants and the synthesis of green nanoparticles.

An Evaluation of the Biocatalyst for the Synthesis and Application of Zinc Oxide Nanoparticles for Water Remediation—A Review

Global water scarcity is threatening the lives of humans, and it is exacerbated by the contamination of water, which occurs because of increased industrialization and soaring population density. The available conventional physical and chemical water treatment techniques are hazardous to living organisms and are not environmentally friendly, as toxic chemical elements are used during these processes. Nanotechnology has presented a possible way in which to solve these issues by using unique materials with desirable properties. Zinc oxide nanoparticles (ZnO NPs) can be used effectively and efficiently for water treatment, along with other nanotechnologies. Owing to rising concerns regarding the environmental unfriendliness and toxicity of nanomaterials, ZnO NPs have recently been synthesized through biologically available and replenishable sources using a green chemistry or green synthesis protocol. The green-synthesized ZnO NPs are less toxic, more eco-friendly, and more biocompatible than other chemically and physically synthesized materials. In this article, the biogenic synthesis and characterization techniques of ZnO NPs using plants, bacteria, fungi, algae, and biological derivatives are reviewed and discussed. The applications of the biologically prepared ZnO NPs, when used for water treatment, are outlined. Additionally, their mechanisms of action, such as the photocatalytic degradation of dyes, the production of reactive oxygen species (ROS), the generation of compounds such as hydrogen peroxide and superoxide, Zn2+ release to degrade microbes, as well as their adsorbent properties with regard to heavy metals and other contaminants in water bodies, are explained. Furthermore, challenges facing the green synthesis of these nanomaterials are outlined. Future research should focus on how nanomaterials should reach the commercialization stage, and suggestions as to how this ought to be achieved are presented.

Current Research on Zinc Oxide Nanoparticles: Synthesis, Characterization, and Biomedical Applications

Zinc oxide nanoparticles (ZnO-NPs) have piqued the curiosity of researchers all over the world due to their extensive biological activity. They are less toxic and biodegradable with the capacity to greatly boost pharmacophore bioactivity. ZnO-NPs are the most extensively used metal oxide nanoparticles in electronic and optoelectronics because of their distinctive optical and chemical properties which can be readily modified by altering the morphology and the wide bandgap. The biosynthesis of nanoparticles using extracts of therapeutic plants, fungi, bacteria, algae, etc., improves their stability and biocompatibility in many biological settings, and its biofabrication alters its physiochemical behavior, contributing to biological potency. As such, ZnO-NPs can be used as an effective nanocarrier for conventional drugs due to their cost-effectiveness and benefits of being biodegradable and biocompatible. This article covers a comprehensive review of different synthesis approaches of ZnO-NPs including physical, chemical, biochemical, and green synthesis techniques, and also emphasizes their biopotency through antibacterial, antifungal, anticancer, anti-inflammatory, antidiabetic, antioxidant, antiviral, wound healing, and cardioprotective activity. Green synthesis from plants, bacteria, and fungus is given special attention, with a particular emphasis on extraction techniques, precursors used for the synthesis and reaction conditions, characterization techniques, and surface morphology of the particles.

Green synthesis and characterization of zinc oxide nanoparticles using bush tea (Athrixia phylicoides DC) natural extract: assessment of the synthesis process

Background: Nanoparticles are globally synthesized for their antimicrobial, anti-inflammatory, wound healing, catalytic, magnetic, optical, and electronic properties that have put them at the forefront of a wide variety of studies. Among them, zinc oxide (ZnO) has received much consideration due to its technological and medicinal applications. In this study, we report on the synthesis process of ZnO nanoparticles using Athrixia phylicoides DC natural extract as a reducing agent.   Methods: Liquid chromatography–mass spectrometry (LC-MS) was used to identify the compounds responsible for the synthesis of ZnO nanoparticles. Structural, morphological and optical properties of the synthesized nanoparticles have been characterized through X-ray diffraction (XRD), Ultraviolet-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS).   Results: LC-MS results showed that different flavonoids and polyphenols, as well as Coumarin, an aromatic compound, reacted with the precursor to form ZnO nanoparticles. XRD and UV-Vis analysis confirmed the synthesis of ZnO nanoparticles, with a spherical shape showed in SEM images. The quasi-spherical ZnO crystals had an average crystallite size of 24 nm. EDS and FTIR analysis confirmed that the powders were pure with no other phase or impurity.   Conclusions: This study successfully demonstrated that the natural plant extract of A. phylicoides DC. can be used in the bio-reduction of zinc nitrate hexahydrate to prepare pure ZnO nanoparticles, thus, extending the use of this plant to an industrial level.

Microbial Mediated Synthesis of Zinc Oxide Nanoparticles, Characterization and Multifaceted Applications

Nanoparticles have gained considerable importance compared to bulk counterparts due to their unique properties. Due to their high surface to volume ratio and high reactivity, metallic and metal-oxide nanostructures have shown great potential applications. Among them, zinc oxide nanoparticles (ZnONPs) have gained tremendous attention attributed to their unique properties such as low toxicity, biocompatibility, simplicity, easy fabrication, and environmental friendly. Remarkably, ZnONPs exhibit optical, physical, antimicrobial, anticancer, anti-inflammatory and wound healing properties. These nanoparticles have been applied in various fields such as in biomedicine, biosensors, electronics, food, cosmetic industries, textile, agriculture and environment. The synthesis of ZnONPs can be performed by chemical, physical and biological methods. Although the chemical and physical methods suffer from some disadvantages such as the involvement of high temperature and pressure conditions, high cost and not environmentally friendly, the green synthesis of ZnONPs offers a promising substitute to these conventional methods. On that account, the microbial mediated synthesis of ZnONPs is clean, eco-friendly, nontoxic and biocompatible method. This paper reviews the microbial synthesis of ZnONPs, parameters used for the optimization process and their physicochemical properties. The potential applications of ZnONPs in biomedical, agricultural and environmental fields as well as their toxic aspects on human beings and animals have been reviewed.

Importance of Protocol Design for Suitable Green In Situ Synthesis of ZnO on Cotton Using Aqueous Extract of Japanese Knotweed Leaves as Reducing Agent

This work presents two protocols for the green in situ synthesis of zinc oxide nanoparticles (ZnO-NP) on cotton with the aim to develop sustainable cotton fabric with an ultraviolet protection factor (UPF). The protocols differed in the order of immersing cotton fabric in reactive solutions of three batches, i.e., precursor (0.1 M zinc acetate dihydrate), reducing agent (aqueous extract of Japanese knotweed leaves) and alkali (wood ash waste). The scanning electron microscope (SEM) results showed that ZnO-NP were successfully synthesised on cotton using both protocols; however, only the protocol where cotton was first immersed in alkali, then in the precursor and, lastly, in the reducing agent enabled very high UPF and higher amount of Zn present on the sample. Due to the different order of cotton fabric immersion in the reactive solutions, dissimilar morphology of the ZnO particles was observed, which resulted in different UV blocking abilities of the samples. The antioxidant analysis (DPPH) showed that the natural reducing agent prepared from Japanese knotweed leaves has very high antioxidant activity, which is attributed to phenolic compounds present in the plant. The reflectance spectroscopy results confirmed that the colour yield and colour of the samples did not influence the UPF value. This protocol is an example of green circular economy where waste materials of invasive alien plant species and pellet heating was used as a natural source of phytochemicals, for the direct synthesis of ZnO-NP to develop cotton fabric with UV-protective properties.

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.

Novel Green In Situ Synthesis of ZnO Nanoparticles on Cotton Using Pomegranate Peel Extract

This work presents the novel and entirely green in situ synthesis of zinc oxide nanoparticles (ZnO-NP) on cotton fabric. Pomegranate peel extract was used as a reducing agent and wood ash extract was used as an alkali source for the formation of ZnO-NP from zinc acetate. Four different synthesis methods, which varied in drying between immersion of fabric in the active solutions for synthesis and the use of padding and ultrasonication, were investigated to evaluate the most suitable one to achieve excellent ultraviolet (UV) protective properties of the functionalized textile. For comparison, the cotton fabrics were also functionalized with each active solution separately or in a combination of two (i.e., Zn-acetate and plant extract). Scanning electron microscopy (SEM), inductively coupled plasma mass spectroscopy (ICP-MS), Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD) analysis, and atomic force microscopy (AFM) confirm the successful formation of ZnO-NP on cotton. Among the synthesis methods, the method that included continuous drying of the samples between immersion in the active solutions for synthesis (Method 4) was found to be the most suitable to deliver uniformly impregnated cotton fibers with numerous small ZnO wurtzite structured crystals and excellent UV protection, with a UV protection factor of 154.0. This research presents an example of a green circular economy where a bio-waste material can be used to produce ZnO-NP directly on cotton at low temperatures and short treatment times without the addition of chemicals and enables the production of cellulosic fabrics with excellent UV protection.

Cell-free extract assisted synthesis of ZnO nanoparticles using aquatic bacterial strains: Biological activities and toxicological evaluation

The introduction of novel bacterial strains and the development of microbial approaches for nanoparticles biosynthesis could minimize the negative environmental impact and eliminate the concern and challenges of the available approaches. In this study, a biological method based on microbial cell-free extract was used for biosynthesis of ZnO NPs using two new aquatic bacteria, Marinobacter sp. 2C8 and Vibrio sp. VLA. The synthesized ZnO NPs were characterized by UV-Visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscope (AFM), dynamic light scattering (DLS) and zeta potential. The UV-Visible absorption peak was found to be at 266 and 250 nm for ZnO-2C8 NPs and ZnO-VLA NPs, respectively. FTIR study suggested that the hydroxyl, amine, and carboxyl groups of bacterial proteins are mainly responsible for stabilizing the biosynthesized ZnO NPs. The formation of hexagonal wurtzite structure of ZnO NPs was confirmed by the XRD pattern. The morphology of the nanoparticles was found to be spherical with the average particle size of about 10.23 ± 2.48 nm and 20.26 ± 4.44 nm for ZnO-2C8 NPs and ZnO-VLA NPs, respectively. The values of zeta potential indicate the high stability of the biosynthesized ZnO NP. Zeta potential values indicated the high stability of the biosynthesized ZnO NP and were obtained -20.54 ± 7.15 and -23.87 ± 2.29 mV for ZnO-2C8 NPs and ZnO-VLA NPs, respectively. The biosynthesized ZnO NPs had antibacterial activity against Gram-negative and Gram-positive strains and possessed excellent antibiofilm activity with the maximum inhibition of about 96.55% at 250 µg/mL. The DPPH activity of ZnO-2C8 NPs and ZnO-VLA NPs were found 88.9% and 85.7% for 2500 μg/mL concentration, respectively. The toxicity test revealed the biocompatibility of the biosynthesized ZnO NPs. The results suggested that this approach is a very good route for synthesizing ZnO NPs with potential applications in biotechnology.

Microbial Nano-Factories: Synthesis and Biomedical Applications

In the recent times, nanomaterials have emerged in the field of biology, medicine, electronics, and agriculture due to their immense applications. Owing to their nanoscale sizes, they present large surface/volume ratio, characteristic structures, and similar dimensions to biomolecules resulting in unique properties for biomedical applications. The chemical and physical methods to synthesize nanoparticles have their own limitations which can be overcome using biological methods for the synthesis. Moreover, through the biogenic synthesis route, the usage of microorganisms has offered a reliable, sustainable, safe, and environmental friendly technique for nanosynthesis. Bacterial, algal, fungal, and yeast cells are known to transport metals from their environment and convert them to elemental nanoparticle forms which are either accumulated or secreted. Additionally, robust nanocarriers have also been developed using viruses. In order to prevent aggregation and promote stabilization of the nanoparticles, capping agents are often secreted during biosynthesis. Microbial nanoparticles find biomedical applications in rapid diagnostics, imaging, biopharmaceuticals, drug delivery systems, antimicrobials, biomaterials for tissue regeneration as well as biosensors. The major challenges in therapeutic applications of microbial nanoparticles include biocompatibility, bioavailability, stability, degradation in the gastro-intestinal tract, and immune response. Thus, the current review article is focused on the microbe-mediated synthesis of various nanoparticles, the different microbial strains explored for such synthesis along with their current and future biomedical applications.

In vitro acaricidal activity of green synthesized nickel oxide nanoparticles against the camel tick, Hyalomma dromedarii (Ixodidae), and its toxicity on Swiss albino mice

The green synthesized nanoparticles have been determined as a novel pesticide against arthropod pests. This study was designed to evaluate the in vitro acaricidal activity of green synthesized nickel oxide nanoparticles (NiO NPs) using aqueous extract of Melia azedarach ripened fruits against different developmental stages of the camel tick Hyalomma dromedarii in addition to their toxic effect on laboratory animals. The synthesized NiO NPs were characterized by UV-visible (UV-Vis) spectroscopy, Fourier transforms infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). The UV-Vis spectra of the NiO NPs showed an absorption peak at 307 nm. FTIR analysis showed the possible functional groups used for capping and stabilization of NiO NPs with strong bands at 3416.2 and 1626.6 cm^-1. The SEM images of the NiO NPs exhibited a size ranging from 21 to 35 nm. The immersion test was used for the in vitro application of the synthesized NiO NPs on the various tick stages (egg, nymph, larva, and adult). Mortality percentages and LC₅₀ values of each tick stage were calculated. The oviposition and hatchability of the engorged females were monitored for the survived tick after treatment. The LC₅₀ values for NiO NPs on embryonated eggs, larvae, and engorged nymphs were 5.00, 7.15, and 1.90 mg/mL, respectively. The egg productive index (EPI), egg number, and hatchability (%) were lower in females treated with the NiO NPs than in control ticks. The toxicity of the NiO NPs on laboratory animals was also investigated using Swiss albino mice by oral dose of 500 mg/kg/day administration for five consecutive days. The hematological, biochemical, and histopathological changes were evaluated. The hematological analysis showed significant increase in the level of white blood cells (WBC) and hemoglobin (Hb). Biochemical analysis showed non-significant decrease in alkaline phosphatase (ALP) and alanine amino transferase (ALT). We concluded that NiO NPs have a significant acaricidal activity as demonstrated on eggs, larvae, engorged nymphs, and fully fed females of H. dromedarii. From a toxicological point of view further in vivo investigations are needed to determine the mechanism of toxic effect of NiO NPs.

Synthesis of ppy–MgO–CNT nanocomposites for multifunctional applications

Cotton is one of the most important raw materials for textile and clothing production. The main drawbacks of cotton fibers are their poor mechanical properties and high flammability. Compared with some synthetic polymer fibers, cotton fabrics treated with modern flame-retardant and reinforcement finishes often cannot meet rigid military specifications. Polypyrrole–magnesium oxide (ppy–MgO) and polypyrrole–magnesium oxide–carbon nanotube (ppy–MgO–CNT) composites were prepared with various weight ratios by in situ chemical polymerization method. 1,2,3,4-Butane tetracarboxylic acid (BTCA) was used as a cross-linking agent in the presence of sodium hypophosphite (SHP). The composite sol was coated on cotton fabric using the pad-dry-cure technique. The coated cotton fabrics were characterized by SEM, EDAX, XRD, UV-DRS and FT-IR analysis, and tested for flame retardant and UPF application. The flame-retardant study showed a maximum char length of 0.3 cm and the char yield was about 49% for the ppy–MgO–CNT composite. For that UPF application, a 30 UPF value was shown for the ppy–MgO–CNT composite. In the case of the antibacterial study, the zone of inhibition was observed for all of the test samples against MRSA and PAO1 bacteria. The zone of inhibition showed as 4.0, 3.0 mm for the ppy–MgO–CNT composite. Hence, the ppy–MgO–CNT composite was found to be efficient.

Cotton is one of the most important raw materials for textile and clothing production.

Novel synthesis of ZnO by Ice-cube method for photo-inactivation of E. coli

The ZnO particle with varieties of morphology was prepared from ice-cube of zinc ammonium complex at boiling water surface in 1 min induction of thermal shock. The zinc ammonium complex in ice cube was developed using zinc acetate and biologically activated ammonia in 1 hr and kept in the freezer. Temperature gradient behaviour of the water medium during thermal shock was captured by the thermal camera and thermometer. Morphology study revealed a variety of flower-like ZnO particles with variable size from 1.0 to 2.5 μm. Further, ZnO particle morphologies were tuned by adding trisodium citrate and hexamine to obtain uniform spherical (2–3 μm) and flower (3–4 μm) shapes, respectively. XRD patterns revealed that all ZnO samples are of a hexagonal structure. Photocatalytic inactivation of E. coli has been investigated using various particle morphologies of ZnO in an aqueous solution/overcoated glass slide under sunlight. The photo-inactivation of E. coli by ZnO particles in suspension condition was better when compared to a coated glass slide method. AFM study confirmed the destruction of bacterial cell wall membrane by the photocatalytic effect. The particles morphology of photocatalyst is well dependent on antibacterial activity under sunlight.

New avenues of controlling microbial infections through anti-microbial and anti-biofilm potentials of green mono-and multi-metallic nanoparticles: A review

Nanoparticles synthesized through the green route deserve special mention because this green technology is not only energy-efficient and cost-effective but also amenable to the environment. Various biological resources have been used for the generation of these 'green nanoparticles'. Biological wastes have also been focused in this direction thereby promoting the value of waste. Reports indicate that green nanoparticles exhibit remarkable antimicrobial activitiesboth singly as well as in combination with standard antibiotics. The current phenomenon of multi-drug resistance has resulted due to indiscriminate administration of high-doses of antibiotics followed by significant toxicity. In the face of this emergence of drug-resistant microbesthe efficacy of green nanoparticles might prove greatly beneficial. Microbial biofilm is another hurdle in the effective treatment of diseases as the microorganismsbeing embedded in the meshwork of the biofilmevade the antimicrobial agents. Nanoparticles may act as a ray of hope on the face of this challenge tooas they not only destroy the biofilms but also lessen the doses of antibiotics requiredwhen administered in combination with the nanoparticles. It should be further noted that the resistance mechanisms exhibited by the microorganisms seem not that relevant for nanoparticles. The current review, to the best of our knowledgefocuses on the structures of these green nanoparticles along with their biomedical potentials. It is interesting to note how a variety of structures are generated by using resources like microbes or plants or plant products and how the structure affects their activities. This study might pave the way for further development in this arena and future work may be taken up in identifying the detailed mechanism by which 'green' synthesis empowers nanoparticles to kill pathogenic microbes.

The cytotoxic properties of zinc oxide nanoparticles on the rat liver and spleen, and its anticancer impacts on human liver cancer cell lines

INTRODUCTION

Due to their unique properties including cellular uptake and the delivery efficiency to biological systems, nanoparticles are used in various preclinical and clinical applications. The aim of this study was to investigate the toxicity impacts of zinc oxide nanoparticles (ZnO-NPs) on morphology and functionality of the rat's liver and spleen and illustrated its safe-therapeutic doses.

METHODS

The 28 female Swiss albino rats (180-220 g) and two human hepatocyte cell lines (HepG2 and HUH7) were designed as an in vivo and in vitro study, respectively. Samples were treated with certain doses of ZnO-NPs. The rat's liver morphology and functionality and apoptotic genes expression profile (Bax, Bcl-2, and P53) were analyzed to detect the cytotoxicity and antitumor impacts of ZnO-NPs, respectively.

RESULTS

The results showed a positive significant association between the increasing doses of ZnO-NPs and alanine aminotransferase/aspartate aminotransferase values. Moreover, a meaningful correlation was detected between the rat's liver and spleen weight and ZnO-NPs doses. Furthermore, the histopathological analysis of rat's liver showed the individual cytotoxic properties of ZnO-NPs. Finally, the positive significant correlation was detected among the expression of Bax and P53 genes with ZnO-NPs. In addition, the negative correlation was demonstrated between the expression of Bcl-2 and ZnO-NPs.

CONCLUSION

In general, in the current study, the antitumor effects of ZnO-NPs were confirmed by the enhancement of P53 and Bax genes expression profile, which are indicated the apoptotic induction in HUH7 cell line. Moreover, we introduced a safe-clinical ZnO-NPs dosage, have antitumor effects.

Biosynthesis of Metal Nanoparticles via Microbial Enzymes: A Mechanistic Approach

During the last decade, metal nanoparticles (MtNPs) have gained immense popularity due to their characteristic physicochemical properties, as well as containing antimicrobial, anti-cancer, catalyzing, optical, electronic and magnetic properties. Primarily, these MtNPs have been synthesized through different physical and chemical methods. However, these conventional methods have various drawbacks, such as high energy consumption, high cost and the involvement of toxic chemical substances. Microbial flora has provided an alternative platform for the biological synthesis of MtNPs in an eco-friendly and cost effective way. In this article we have focused on various microorganisms used for the synthesis of different MtNPs. We also have elaborated on the intracellular and extracellular mechanisms of MtNP synthesis in microorganisms, and have highlighted their advantages along with their challenges. Moreover, due to several advantages over chemically synthesized nanoparticles, the microbial MtNPs, with their exclusive and dynamic characteristics, can be used in different sectors like the agriculture, medicine, cosmetics and biotechnology industries in the near future.

Facile and Versatile Modification of Cotton Fibers for Persistent Antibacterial Activity and Enhanced Hygroscopicity

Natural fibers with functionalities have attracted considerable attention. However, developing facile and versatile strategies to modify natural fibers is still a challenge. In this study, cotton fibers, the most widely used natural fibers, were partially oxidized by sodium periodate in aqueous solution, to give oxidized cotton fibers containing multiple aldehyde groups on their surface. Then poly(hexamethylene guanidine) was chemically grafted onto the oxidized cotton fibers forming Schiff bases between the terminal amines of poly(hexamethylene guanidine) and the aldehyde groups of oxidized cotton fibers. Finally, carbon-nitrogen double bonds were reduced by sodium cyanoborohydride, to bound poly(hexamethylene guanidine) covalently to the surface of cotton fibers. These functionalized fibers show strong and persistent antibacterial activity: complete inhibition against Escherichia coli and Staphylococcus aureus was maintained even after 1000 consecutive washing in distilled water. On the other hand, cotton fibers with only physically adsorbed poly(hexamethylene guanidine) lost their antibacterial activity entirely after a few washes. According to Cell Counting Kit-8 assay and hemolytic analysis, toxicity did not significantly increase after chemical modification. Attributing to the hydrophilicity of poly(hexamethylene guanidine) coatings, the modified cotton fibers were also more hygroscopic compared to untreated cotton fibers, which can improve the comfort of the fabrics made of modified cotton fibers. This study provides a facile and versatile strategy to prepare modified polysaccharide natural fibers with durable antibacterial activity, biosecurity, and comfortable touch.

A Review on Green Synthesis, Biomedical Applications, and Toxicity Studies of ZnO NPs

The advance of reliable and eco-friendly strategies for the development of nanoparticles is a fundamental key to the discipline of nanotechnology. Nanoparticles have been continuously evaluated and have been used in many industrial applications for a decade. In particular, the role of zinc oxide nanoparticles (ZnO NPs) has received a great interest because of various properties such as UV filter properties and photochemical, antifungal, high catalyst, and antimicrobial activities. Because of the high rate of poisonous chemicals and the extreme surroundings used within the chemical and physical methods, the green techniques have been adopted using plants, fungi, bacteria, and algae for the synthesis of nanoparticles. Therefore, this paper considers various green synthesis methods to provide the evidence of ZnO NP role to several applications, and in addition, biomedical applications and toxic effect were reviewed. Therefore, the paper used various secondary sources to collect the relevant review articles. From the findings, the green route of synthesis is rather safe and eco-friendly when compared to physical and chemical means of synthesis. On the other hand, its biomedical applications in this sector are increased day by day in various processes including bioimaging, drug delivery, biosensors, and gene delivery. With respect to its toxicity properties, ZnO NPs can act as smart weapons against multiple drug-resistant microorganisms and as a talented substitute for antibiotics.

Production and Characterization of Superhydrophobic and Antibacterial Coated Fabrics Utilizing ZnO Nanocatalyst

Dirt and microorganisms are the major problems in textiles which can generate unpleasant odor during their growth. Here, zinc oxide (ZnO) nanoparticles prepared by sol-gel method were loaded on the cotton fabrics using spin coating technique to enhance their antimicrobial properties and water repellency. The effects of ZnO precursor concentration, precursor solution pH, number of coating runs, and Mg doping percent on the structures, morphologies, and water contact angles (WCA) of the ZnO-coated fabrics were addressed. At 0.5 M concentration and pH7, more homogeneous and smaller ZnO nanoparticles were grown along the preferred (0 0 2) direction and uniformly distributed on the fabric with a crystallite size 17.98 nm and dislocation density 3.09 × 10-3 dislocation/nm2. The substitution of Zn 2+ with Mg 2+ ions slightly shifted the (002) peak position to a higher angle. Also, the zeta potential and particle size distribution were measured for ZnO nanoparticle suspension. A superhydrophobic WCA = 154° was measured for the fabric that coated at 0.5 M precursor solution, pH 7, 20 runs and 0% Mg doping. Moreover, the antibacterial activities of the ZnO-coated fabric were investigated against some gram-positive and gram-negative bacteria such as Salmonella typhimurium, Klebsiella pneumonia, Escherichia coli, and Bacillus subtilis.

Nanoscale wide-band semiconductors for photocatalytic remediation of aquatic pollution

Water pollution is a serious challenge to the public health. Among different forms of aquatic pollutants, chemical and biological agents create paramount threat to water quality when the safety standards are surpassed. There are many conventional remediatory strategies that are practiced such as resin-based exchanger and activated charcoal/carbon andreverse osmosis. Newer technologies using plants, microorganisms, genetic engineering, and enzyme-based approaches are also proposed for aquatic pollution management. However, the conventional technologies have shown impending inadequacies. On the other hand, new bio-based techniques have failed to exhibit reproducibility, wide specificity, and fidelity in field conditions. Hence, to solve these shortcomings, nanotechnology ushered a ray of hope by applying nanoscale zinc oxide (ZnO), titanium dioxide (TiO₂), and tungsten oxide (WO₃) particles for the remediation of water pollution. These nanophotocatalysts are active, cost-effective, quicker in action, and can be implemented at a larger scale. These nanoparticles are climate-independent, assist in complete mineralization of pollutants, and can act non-specifically against chemically and biologically based aquatic pollutants. Photocatalysis for environmental remediation depends on the availability of solar light. The mechanism of photocatalysis involves the formation of electron-hole pairs upon light irradiations at intensities higher than their band gap energies. In the present review, different methods of synthesis of nanoscale ZnO, TiO₂, and WO₃ as well as their structural characterizations have been discussed. Photodegradation of organic pollutants through mentioned nanoparticles has been reviewed with recent advancements. Enhancing the efficacy of photocatalysis through doping of TiO₂ and ZnO nanoparticles with non-metals, metals, and metal ions has also been documented in this report.

Synthesis of chitosan incorporated neem seed extract (Azadirachta indica) for medical textiles

In present study, eco-friendly biosynthesis of Chitosan-Neem seed (CS-NS) composite was prepared by co-precipitation method using aqueous neem seed extract. Cotton fabrics were treated with two different crosslinking agents (Glutaraldehyde and Citric acid) then the synthesized composite coated on cotton fabric by chemical linkage between the composite and the cellulose structure. As synthesized composite materials and treated cotton fabrics were characterized by Fourier transform infrared spectroscopy for functional groups confirmation, X-ray diffraction for crystalline behavior determination, UV-vis spectroscopy analysis for optical property and High resolution scanning electron microscopy for Surface morphological properties. The antibacterial activity of CS-NS composite coated cotton fabric and CS-NS composite coated cotton fabric with crosslinking agents were tested against the gram-positive and gram negative bacteria by agar well diffusion method. The results demonstrated that CS-NS composite with crosslinked coated cotton fabric has higher antibacterial activity than without crosslinked cotton fabric. Thus the chitosan-neem seed composite may be applied to the medical textiles.

Long-term antibacterial protected cotton fabric coating by controlled release of chlorhexidine gluconate from halloysite nanotubes

An antibacterial HNTs/CG composite with controlled release was prepared, and used to coat cotton to obtain an antibacterial and biocompatible cotton fabric.

A review on biogenic synthesis of ZnO nanoparticles using plant extracts and microbes: A prospect towards green chemistry

Nanotechnology is emerging as an important area of research with its tremendous applications in all fields of science, engineering, medicine, pharmacy, etc. It involves the materials and their applications having one dimension in the range of 1-100nm. Generally, various techniques are used for syntheses of nanoparticles (NPs) viz. laser ablation, chemical reduction, milling, sputtering, etc. These conventional techniques e.g. chemical reduction method, in which various hazardous chemicals are used for the synthesis of NPs later become liable for innumerable health risks due to their toxicity and endangering serious concerns for environment, while other approaches are expensive, need high energy for the synthesis of NPs. However, biogenic synthesis method to produce NPs is eco-friendly and free of chemical contaminants for biological applications where purity is of concerns. In biological method, different biological entities such as extract, enzymes or proteins of a natural product are used to reduce and stabilised formation of NPs. The nature of these biological entities also influence the structure, shape, size and morphology of synthesized NPs. In this review, biogenic synthesis of zinc oxide (ZnO) NPs, procedures of syntheses, mechanism of formation and their various applications have been discussed. Various entities such as proteins, enzymes, phytochemicals, etc. available in the natural reductants are responsible for synthesis of ZnO NPs.