Green synthesis of highly stable carbon nanodots and their photocatalytic performance

The present study reports a novel, facile, biosynthesis route for the synthesis of carbon nanodots (CDs) with an approximate quantum yield of 38.5%, using Musk melon extract as a naturally derived‐precursor material. The synthesis of CDs was established by using ultraviolet–visible (UV–vis) spectroscopy, Dynamic light scattering, photoluminescence spectroscopy, X‐ray diffraction, transmission electron microscopy and Fourier transform infrared (FTIR) spectroscopy. The as‐prepared CDs possess an eminent fluorescence under UV–light (λ _ex  = 365 nm). The size range of CDs was found to be in the range of 5–10 nm. The authors further explored the use of such biosynthesised CDs as a photocatalyst material for removal of industrial dye. Degradation of methylene blue dye was performed in a photocatalytic reactor and monitored using UV–vis spectroscopy. The CDs show excellent dye degradation capability of 37.08% in 60 min and reaction rate of 0.0032 min⁻¹. This study shows that synthesised CDs are highly stable in nature, and possess potential application in wastewater treatment.Inspec keywords: carbon, nanostructured materials, nanofabrication, catalysis, photochemistry, ultraviolet spectra, visible spectra, photoluminescence, X‐ray diffraction, transmission electron microscopy, Fourier transform infrared spectra, fluorescence, dyesOther keywords: green synthesis, highly stable CD, photocatalytic performance, biosynthesis route, carbon nanodots, quantum yield, Musk melon extract, naturally derived‐precursor material, ultraviolet‐visible spectroscopy, dynamic light scattering, photoluminescence spectroscopy, X‐ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, FTIR spectroscopy, fluorescence, biosynthesised CD, photocatalyst material, industrial dye, methylene blue dye degradation, photocatalytic reactor, UV‐vis spectroscopy, wastewater treatment, size 5 nm to 10 nm, time 60 min     

Synthesis,characterisation and bactericidal effect of ZnO nanoparticles via chemical and bio‐assisted (Silybum marianum in vitro plantlets and callus extract) methods: a comparative study

Currently, the evolution of green chemistry in the synthesis of nanoparticles (NPs) with the usage of plants has captivated a great response. In this study, in vitro plantlets and callus of Silybum marianum were exploited as a stabilising agent for the synthesis of zinc oxide (ZnO) NPs using zinc acetate and sodium hydroxide as a substitute for chemical method. The contemporary investigation defines the synthesis of ZnO NPs prepared by chemical and bio‐extract‐assisted methods. Characterisation techniques such as X‐ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy and energy dispersive X‐ray were used to confirm the synthesis. Although chemical and bio‐assisted methods are suitable choices for NPs synthesis, the bio‐assisted green assembly is advantageous due to superior stability. Moreover, this report describes the antibacterial activity of the synthesised NPs against standard strains of Klebsiella pneumonia and Bacillus subtilis.Inspec keywords: zinc compounds, II‐VI semiconductors, wide band gap semiconductors, nanoparticles, nanofabrication, semiconductor growth, antibacterial activity, X‐ray diffraction, X‐ray chemical analysis, scanning electron microscopy, Fourier transform infrared spectra, nanobiotechnologyOther keywords: chemical methods, bio‐assisted methods, Silybum marianum in vitro plantlets methods, Silybum marianum in vitro callus extract methods, green chemistry, zinc oxide nanoparticles, sodium hydroxide, zinc acetate, X‐ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, energy dispersive X‐ray analysis, bio‐assisted green assembly, antibacterial activity, Klebsiella pneumonia, Bacillus subtilis, ZnO     

Green synthesis of silver nanoparticles with the Arial part of Dorema ammoniacum D. extract by antimicrobial analysis

Silver nanoparticles (SNPs) were synthesised by using the Arial part extract of Dorema ammoniacum D. and characterised by employing UV–visible spectroscopy, Fourier transform infrared spectroscopy and X‐ray diffraction techniques. Transmission electron microscopy and field emission scanning electron microscopy were applied to investigate the morphological structure of the bio‐synthesised SNPs. The antimicrobial activity of SNPs was studied against Gram positive (Bacillus cereus and Staphylococcus aureus) and Gram‐negative (Escherichia coli and Salmonella typhimurium) bacteria by employing the disk diffusion agar process. An extremely antimicrobial effect was observed for SNPs. Utilising D. ammoniacum D. as a mediator for the synthesis of SNPs helped to save time and cost.Inspec keywords: silver, nanoparticles, nanofabrication, nanomedicine, biomedical materials, particle size, antibacterial activity, visible spectra, ultraviolet spectra, microorganisms, field emission scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, surface diffusionOther keywords: green synthesis, silver nanoparticles, Dorema ammoniacum D. extract, antimicrobial analysis, Arial part extract, UV‐visible spectroscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, transmission electron microscopy, field emission scanning electron microscopy, morphological structure, bio‐synthesised SNPs, antimicrobial activity, gram positive Bacillus cereus bacteria, gram positive Staphylococcus aureus bacteria, gram‐negative Escherichia coli bacteria, gram‐negative Salmonella typhimurium bacteria, disk diffusion agar process, antimicrobial effect, Ag     

Biosynthesis of the CuO nanoparticles using Euphorbia Chamaesyce leaf extract and investigation of their catalytic activity for the reduction of 4‐nitrophenol

Through this study an eco‐friendly, simple, efficient, cheap and biocompatible approach to the biosynthesis and stabilisation of CuO nanoparticles (NPs) using the Euphorbia Chamaesyce leaf extract is presented. The CuO NPs were monitored and characterised by field emission scanning electron microscopy, energy dispersive X‐ray spectroscopy, Fourier transformed infrared spectroscopy, transmission electron microscope and UV‐visible spectroscopy. The biosynthesised CuO NPs showed good catalytic activity for the reduction of 4‐nitrophenol (4‐NP) in water during 180 s and reused 4 times without considerable loss of activity.Inspec keywords: copper compounds, nanoparticles, nanofabrication, catalysis, reduction (chemical), field emission electron microscopy, X‐ray chemical analysis, Fourier transform infrared spectra, transmission electron microscopy, ultraviolet spectra, visible spectraOther keywords: biosynthesis, CuO nanoparticles, Euphorbia Chamaesyce leaf extract, catalytic activity, 4‐nitrophenol reduction, nanoparticle stabilisation, field emission scanning electron microscopy, energy dispersive X‐ray spectroscopy, Fourier transformed infrared spectroscopy, transmission electron microscope, UV‐visible spectroscopy, CuO     

Enhancement of secondary metabolites in Bacopa monnieri (L.) Pennell plants treated with copper‐based nanoparticles in vivo

The study aims to document the effect of starch‐stabilised copper‐based nanoparticles (CuNPs) on the biosynthesis of pharmaceutically valuable secondary metabolites, especially saponins, of the reputed nootropic herb Bacopa monnieri (L.) Pennell. CuNPs were synthesised chemically by the reduction of cupric sulphate pentahydrate with ascorbic acid using starch as the capping agent. They were characterised by UV–visible spectrophotometry, Fourier‐transform infra‐red spectroscopy, X‐ray diffraction, high‐resolution transmission electron microscopy and zeta potential. The nanoparticles consisted of cuprous oxide and metallic copper, were approximately spherical, polydispersed with diameter <20 nm. Hydroponically grown B. monnieri plants were treated in vivo with the CuNPs between the concentrations of 0–100 mg l⁻¹. Spectrophotometric estimation of the total contents of saponins, alkaloids, phenolics, flavonoids and DPPH radical scavenging capacity from the methanolic extracts of the whole plants showed a hormetic increase in the content of secondary metabolites in a concentration‐dependent manner from 5 mg l⁻¹ until it declined at toxic metabolic concentration. This was accompanied by an increase in ROS markers hydrogen peroxide and malondialdehyde as well as a hormetic effect on activities of phenylalanine ammonia lyase and antioxidant enzymes catalase, ascorbate peroxidase and superoxide dismutase. CuNPs at sub‐toxic concentrations were found to enhance secondary metabolism and antioxidant capacity in Bacopa monnieri through ROS‐mediated defence response.Inspec keywords: organic compounds, pharmaceuticals, copper compounds, visible spectra, nanofabrication, hydrogen compounds, transmission electron microscopy, reduction (chemical), ultraviolet spectra, electrokinetic effects, X‐ray diffraction, nanoparticles, toxicology, copper, enzymes, Fourier transform infrared spectra, health and safety, agricultural productsOther keywords: starch‐stabilised copper‐based nanoparticles, secondary metabolites, cupric sulphate pentahydrate, capping agent, UV–visible spectrophotometry, X‐ray diffraction, high‐resolution transmission electron microscopy, DPPH radical scavenging capacity, toxic metabolic concentration, antioxidant capacity, saponin content, chemical reduction, ascorbic acid, Fourier transform infrared spectroscopy, zeta potential, hydroponical growth, methanolic extracts, alkaloid content, flavonoid content, malondialdehyde, phenylalanine ammonia lyase, antioxidant enzymes catalase, ascorbate peroxidase, superoxide dismutase, sub‐toxic concentration, spectrophotometric estimation, phenolic content, Pennell plants, Bacopa monnieri L, in vivo treatment, ROS‐mediated defence response, Cu, Cu₂ O, H₂ O₂ , CuSO₄ H₂ O     

Green synthesis of CuO nanoparticles loaded on the seashell surface using Rumex crispus seeds extract and its catalytic applications for reduction of dyes

In this study, CuO nanoparticles supported on the seashell (CuO NPs/seashell) was prepared using Rumex crispus seeds extract as a chelating and capping agent. The prepared nanocomposite was characterised by Fourier transform infrared spectroscopy, X‐ray diffraction, field emission scanning electron microscopy, energy‐dispersive X‐ray spectroscopy and transmission electron microscopy. The particle size of CuO NPs on the seashell sheets was in the range of 8–60 nm. Catalytic ability of CuO NPs/seashell was investigated for the reduction of 4‐nitrophenol (4‐NP) and Congo red (CR). It was observed that catalyst can be easily recovered and reused several times without any significant loss of catalytic efficiency.Inspec keywords: nanocomposites, nanoparticles, catalysis, dyes, Fourier transform infrared spectra, X‐ray diffraction, field emission electron microscopy, scanning electron microscopy, X‐ray chemical analysis, transmission electron microscopy, particle size, copper compoundsOther keywords: CuO, size 8 nm to 60 nm, Congo red, 4‐nitrophenol, particle size, transmission electron microscopy, energy dispersive X‐ray spectroscopy, field emission scanning electron microscopy, X‐ray diffraction, Fourier transform infrared spectroscopy, nanocomposite, capping agent, chelating agent, dye reduction, catalytic application, Rumex crispus seeds extract, seashell surface, nanoparticles, green synthesis     

Nitrobacter sp. extract mediated biosynthesis of Ag2 O NPs with excellent antioxidant and antibacterial potential for biomedical application

In this study, extracellular extract of plant growth promoting bacterium, Nitrobacter sp. is used for the bioconversion of AgNO₃ (silver nitrate) into Ag₂ O (silver oxide nanoparticles). It is an easy, ecofriendly and single step method for Ag₂ O NPs synthesis. The bio‐synthesized nanoparticles were characterized using different techniques. UV‐Vis results showed the maximum absorbance around 450 nm. XRD result shows the particles to have faced centered cubic (fcc) crystalline nature. FTIR analysis reveals the functional groups that are involved in bioconversion such as C–N, N–H and C=O. Energy‐dispersive X‐ray spectroscopy (EDAX) spectrum confirms that the prepared nanoparticle is Ag₂ O NPs. Particle size distribution result reveals that the average particle size is around 40 nm. The synthesized Ag₂ O NPs found to be almost spherical in shape. Biosynthesized Ag₂ O NPs possess good antibacterial activity against selected Gram positive and Gram negative bacterial strains namely Salmonella typhimurium, Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae when compared to standard antibiotic. In addition, Ag₂ O NPs exhibits excellent free radical scavenging activity with respect to dosage. Thus, this study is a new approach to use soil bacterial extract for the production of Ag₂ O NPs for biomedical application.Inspec keywords: nanomedicine, nanoparticles, silver compounds, antibacterial activity, ultraviolet spectra, visible spectra, X‐ray diffraction, Fourier transform infrared spectra, X‐ray chemical analysis, particle size, free radicalsOther keywords: free radical scavenging activity, Ag₂ O, AgNO₃ , Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, Salmonella typhimurium, Gram negative bacterial strains, Gram positive bacterial strains, particle size distribution, energy‐dispersive X‐ray spectroscopy spectrum, functional groups, Fourier transform infrared analysis, faced centred cubic crystalline nature, XRD, UV‐Vis results, bio‐synthesised nanoparticles, silver oxide nanoparticles, silver nitrate bioconversion, plant growth promoting bacterium, extracellular extract, biomedical application, antibacterial potential, antioxidant potential, Ag₂ O NPs, extract mediated biosynthesis, Nitrobacter sp     

Role of catalytic protein and stabilising agents in the transformation of Ag ions to nanoparticles by Pseudomonas aeruginosa

Biological routes of synthesising metal nanoparticles (NPs) using microbes have been gaining much attention due to their low toxicity and eco‐friendly nature. Pseudomonas aeruginosa JP2 isolated from metal contaminated soil was evaluated towards extracellular synthesis of silver NPs (AgNPs). Cell‐free extract (24 h) of the bacterial isolate was reacted with AgNO₃ for 24 h in order to fabricate AgNPs. Preliminary observations were recorded in terms of colour change of the reaction mixture from yellow to greyish black. UV‐visible spectroscopy of the reaction mixture has shown a progressive increase in optical densities that correspond to peaks near 430 nm, depicting reduction of ionic silver (Ag⁺) to atomic silver (Ag⁰) thereby synthesising NPs. X‐ray diffraction spectra exhibited the 2θ values to be 38.4577° confirming the crystalline and spherical nature of NPs [9.6 − 26.7 (Ave. = 17.2 nm)]. Transmission electron microscopy finally confirmed the size of the particles varying from 5 to 60 nm. Moreover, rhamnolipids and proteins were identified as stabilising molecules for the AgNPs through Fourier transform‐infrared spectroscopy. Characterisation of bacterial crude and purified protein fractions confirmed the involvement of nitrate reductase (molecular weight 66 kDa and specific activity = 3.8 U/mg) in the Synthesis of AgNPs.Inspec keywords: microorganisms, silver, nanoparticles, enzymes, molecular biophysics, ultraviolet spectra, visible spectra, X‐ray diffraction, transmission electron microscopy, Fourier transform infrared spectra, catalysis, biochemistry, nanobiotechnologyOther keywords: catalytic protein, stabilising agents, Pseudomonas aeruginosa, metal nanoparticles, UV–visible spectroscopy, optical densities, ionic silver, atomic silver, X‐ray diffraction spectra, transmission electron microscopy, nitrate reductase, rhamnolipids, Fourier transform‐infrared spectroscopy, Ag     

Silver nanoparticles biologically synthesised using tea leaf extracts and their use for extension of fruit shelf life

The biosynthesis of nanoparticles (NPs) from plant extracts is important in nanotechnology because the employed methods are environmentally friendly and cost‐effective. In this study, silver NPs (AgNPs) were synthesised using Chinese tea (Oolong tea) extract. The effects of the relative content of the employed silver nitrate, the reaction temperature, the incubation time, and the tea‐to‐water ratio on the formation of the AgNPs were examined. The synthesised AgNPs were also analysed by UV–vis spectroscopy, dynamic light scattering, transmission electron microscopy, X‐ray diffraction, Fourier transform infrared spectroscopy, and thermo‐gravimetric analysis. The NPs were observed to be highly crystalline, approximately spherical, and 10–50 nm in diameter. They were also tested for their use in preserving the postharvest quality of cherry tomatoes, with good results obtained. The tea AgNP treatment was specifically found to reduce the weight loss of the tomatoes, as well as changes in their total soluble solids, vitamin C, and titratable acid contents. The findings of this study indicate that postharvest tea AgNP treatment affords a clean, safe, high‐quality, and environmentally friendly method for extending the shelf life of fruits.Inspec keywords: silver, nanoparticles, nanofabrication, ultraviolet spectra, visible spectra, light scattering, transmission electron microscopy, X‐ray diffraction, Fourier transform infrared spectra, thermal analysisOther keywords: silver nanoparticles, tea leaf extracts, fruit shelf life, Chinese tea extract, Oolong tea, silver nitrate, reaction temperature, incubation time, tea‐water ratio, UV‐vis spectroscopy, dynamic light scattering, transmission electron microscopy, X‐ray diffraction, Fourier transform infrared spectroscopy, thermo‐gravimetric analysis, cherry tomatoes, Ag     

Green synthesis,characterisation and bioactivity of plant‐mediated silver nanoparticles using Decalepis hamiltonii root extract

Consistent search of plants for green synthesis of silver nanoparticles (SNPs) is an important arena in Nanomedicine. This study focuses on synthesis of SNPs using bioreduction of silver nitrate (AgNO₃) by aqueous root extract of Decalepis hamiltonii. The biosynthesis of SNPs was monitored by UV–vis analysis at absorbance maxima 432 nm. The fluorescence emission spectra of SNPs illustrated the broad emission peak 450–483 nm at different excitation wavelengths. The surface characteristics were studied by scanning electron microscope and atomic force microscopy, showed spherical shape of SNPs and dynamic light scattering analysis confirmed the average particle size 32.5 nm and the presence of metallic silver was confirmed by energy dispersive X‐ray. Face centred cubic structure with crystal size 33.3 nm was revealed by powder X‐ray diffraction. Fourier transform infrared spectroscopy indicated the biomolecules involved in the reduction mainly polyols and phenols present in root extracts were found to be responsible for the synthesis of SNPs. The stability and charge on SNPs were revealed by zeta potential analysis. In addition, on therapeutic forum, the synthesised SNPs elicit antioxidant and antimicrobial activity against Bacillus cereus, Bacillus licheniformis, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus.Inspec keywords: silver, nanoparticles, nanomedicine, antibacterial activity, biomedical materials, nanofabrication, particle size, microorganisms, ultraviolet spectra, visible spectra, fluorescence, scanning electron microscopy, atomic force microscopy, light scattering, X‐ray diffraction, X‐ray chemical analysis, Fourier transform infrared spectra, molecular biophysics, electrokinetic effectsOther keywords: phenols, zeta potential analysis, therapeutic forum, antioxidant activity, antimicrobial activity, Bacillus cereus, Bacillus licheniformis, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Ag, polyols, biomolecules, Fourier transform infrared spectroscopy, powder X‐ray diffraction, crystal size, face centred cubic structure, energy dispersive X‐ray analysis, metallic silver, particle size, dynamic light scattering analysis, spherical shape, atomic force microscopy, scanning electron microscopy, surface characteristics, excitation wavelengths, fluorescence emission spectra, UV‐visible analysis, biosynthesis, silver nitrate bioreduction, nanomedicine, Decalepis hamiltonii aqueous root extract, bioactivity, plant‐mediated silver nanoparticles, green synthesis     

Green synthesis of the Ag/ZnO nanocomposite using Valeriana officinalis L. root extract: application as a reusable catalyst for the reduction of organic dyes in a very short time

A facile and green synthesis of the Ag/ZnO nanocomposite by extract of Valeriana officinalis L. root in the absence of any stabiliser or surfactant has been reported in this work. The green synthesised Ag/ZnO nanocomposite was characterised by Field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy dispersive X‐ray spectroscopy (EDS), elemental mapping, Fourier‐Transform infrared (FT‐IR), X‐ray diffraction analysis (XRD) and UV‐Vis spectroscopy. According to SEM and TEM images, the Ag and ZnO particles are spherical with diameters of less than 20 and 40–50 nm, respectively. The Ag NPs/ZnO nanocomposite proved to be an effective catalyst in the reduction of various dyes including methyl orange (MO), Congo red (CR) and methylene blue (MB) in the presence of NaBH₄ in aqueous media at ambient temperature. A maximum degradation (100%) of dyes was performed using Ag/ZnO nanocomposite. The extraordinary performance of the prepared Ag/ZnO nanocomposite is attributed to the synergetic effect induced by both ZnO and Ag NPs in the catalytic degradation of organic dyes. The catalyst could be reused and recovered several times with no significant loss of catalytic activity.Inspec keywords: nanocomposites, silver, zinc compounds, II‐VI semiconductors, nanofabrication, catalysts, reduction (chemical), field emission electron microscopy, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectra, ultraviolet spectra, visible spectra, X‐ray diffraction, surface morphology, nanoparticles, dyesOther keywords: green synthesis, nanocomposite, Valeriana officinalis L. root extract, reusable catalyst, reduction, organic dyes, surfactant, field emission scanning electron microscopy, transmission electron microscopy, energy dispersive X‐ray spectroscopy, elemental mapping, Fourier‐transform infrared spectroscopy, X‐ray diffraction analysis, surface morphology, nanoparticles, methyl orange, congo red, methylene blue, UV–Vis spectroscopy, size 40 nm to 50 nm, wavelength 493 nm, wavelength 465 nm, wavelength 663 nm, Ag‐ZnO     

Role of Ribes khorassanicum in the biosynthesis of AgNPs and their antibacterial properties

Silver nanoparticles (AgNPs) have been biosynthesised through the extracts of Ribes khorassanicum fruits, which served as the reducing agents and capping agents. Biosynthesised AgNPs have been found to be ultraviolet–visible (UV–vis) absorption spectra since they have displayed one surface plasmon resonance peak at 438 nm, attesting the formation of spherical NPs. These particles have been characterised by UV–vis, field‐emission scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, X‐ray diffraction, Fourier transform infrared spectroscopy, and transmission electron microscopy analysis. The formation of AgNPs at 1.0 mM concentration of AgNO₃ has resulted in NPs that contained mean diameters in a range of 20–40 nm. The green‐synthesised AgNPs have demonstrated high antibacterial effect against pathogenic bacteria (i.e. Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa). Biosynthesising metal NPs through plant extracts can serve as the facile and eco‐friendly alternative for chemical and/or physical methods that are utilised for large‐scale nanometal fabrication in various medical and industrial applications.Inspec keywords: X‐ray diffraction, X‐ray chemical analysis, nanofabrication, surface plasmon resonance, nanoparticles, antibacterial activity, microorganisms, scanning electron microscopy, silver, nanomedicine, visible spectra, ultraviolet spectra, transmission electron microscopy, Fourier transform infrared spectra, field emission scanning electron microscopy, biomedical materialsOther keywords: antibacterial properties, silver nanoparticles, reducing agents, capping agents, surface plasmon resonance peak, spherical NPs, field‐emission scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, X‐ray diffraction, transmission electron microscopy analysis, plant extracts, ultraviolet‐visible absorption spectra, Fourier transform infrared spectroscopy, antibacterial effect, Ribes khorassanicum fruits, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, surface plasmon resonance, AgNO₃ , Ag     

Fabrication and characterisation of silver nanoparticles using bract extract of Musa paradisiaca for its synergistic combating effect on phytopathogens,free radical scavenging activity,and catalytic efficiency

This work explores the rapid synthesis of silver nanoparticles (AgNPs) from Musa paradisiaca (M. paradisiaca) bract extract. The bio‐reduction of Ag⁺ ion was recorded using ultraviolet–visible spectroscopy by a surface plasmon resonance extinction peak with an absorbance at 420 nm. The phytoconstituents responsible for the reduction of AgNPs was probed using Fourier transform infrared spectroscopy. The X‐ray diffraction pattern confirmed the formation of crystalline AgNPs that were analogous to selected area electron diffraction patterns. Morphological studies showed that the obtained AgNPs were monodispersed with an average size of 15 nm. The biologically synthesised AgNPs showed higher obstruction against tested phytopathogens. The synthesised AgNPs exhibited higher inhibitory zone against fungal pathogen Alternaria alternata and bacterial pathogen Pseudomonas syringae. Free radical scavenging potential of AgNPs was investigated using 1,1‐diphenyl‐2‐picryl hydroxyl and 2,2‐azinobis (3‐ethylbenzothiazoline)‐6‐sulphonic acid assays which revealed that the synthesised AgNPs act as a potent radical scavenger. The catalytic efficiency of the synthesised AgNPs was investigated for azo dyes, methyl orange (MO), methylene blue (MB) and reduction of o‐nitrophenol to o‐aminophenol. The results portrayed that AgNPs act as an effective nanocatalyst to degrade MO to hydrazine derivatives, MB to leucomethylene blue, and o‐nitro phenol to o‐amino phenolInspec keywords: catalysis, dyes, electron diffraction, nanofabrication, silver, catalysts, surface plasmon resonance, reduction (chemical), free radicals, nanoparticles, transmission electron microscopy, nanobiotechnology, X‐ray diffraction, microorganisms, organic compounds, Fourier transform spectra, nanomedicine, visible spectra, antibacterial activity, infrared spectra, ultraviolet spectraOther keywords: silver nanoparticles, musa paradisiaca, synergistic combating effect, free radical scavenging activity, catalytic efficiency, M. paradisiaca, bio‐reduction, ultraviolet–visible spectroscopy, surface plasmon resonance extinction peak, Fourier transform infrared spectroscopy, X‐ray diffraction pattern, selected area electron diffraction patterns, radical scavenging potential, potent radical scavenger, size 420.0 nm, size 15.0 nm, Ag⁺      

Eco‐friendly synthesis of silver and gold nanoparticles with enhanced antimicrobial,antioxidant, and catalytic activities

The present work is emphasised on the bio‐fabrication of silver and gold nanoparticles in a single step by a microwave‐assisted method using the leaf extract of Synedrella nodiflora as both reducing and stabilising agent. The synthesised nanoparticles are highly stable and show surface plasmon resonance peak at 413 and 535 nm, respectively, for silver and gold nanoparticles in UV–Vis spectrum. The functional group responsible for the reduction of metal ions were obtained from Fourier transform infrared spectroscopy. The crystalline nature of nanoparticles with face‐centred cubic geometry was confirmed by the X‐ray diffraction and selected area electron diffraction patterns. The morphology and sizes of the silver and gold nanoparticles were obtained from transmission electron microscopy images. The nanoparticles exhibit effective antimicrobial activities against various pathogenic strains. These antimicrobial properties were analysed by employing agar well diffusion method. The nanoparticles show significant antioxidant properties, and it was determined using 2, 2‐diphenyl‐1‐picrylhydrazyl assay. The nanoparticles also show potent catalytic activity in the degradation of anthropogenic pollutant dyes Congo red and eosin Y by excess NaBH₄. Thus, the current study demonstrates the potential use of S. nodiflora as a reducing and stabilising agent for the synthesis of silver and gold nanoparticles and their relevance in the field of biomedicine and catalysis.Inspec keywords: transmission electron microscopy, visible spectra, surface plasmon resonance, nanofabrication, ultraviolet spectra, field emission electron microscopy, reduction (chemical), nanocomposites, microorganisms, nanoparticles, dyes, silver, X‐ray diffraction, nanomedicine, gold, antibacterial activity, electron diffraction, infrared spectra, particle size, Fourier transform spectra, scanning electron microscopy, catalysis, crystal growth from solutionOther keywords: synthesised nanoparticles, gold nanoparticles, catalytic activities, electron diffraction patterns, antimicrobial activities, antioxidant activities, transmission electron microscopy images, X‐ray diffraction, 2,2‐diphenyl‐1‐picrylhydrazyl assay, Synedrella nodiflora, UV–Vis spectrum, silver nanoparticles, biofabrication, surface plasmon resonance, Fourier transform infrared spectroscopy, face‐centred cubic geometry, area electron diffraction patterns, pathogenic strains, agar well diffusion method, anthropogenic pollutant dyes, Congo red, eosin Y, wavelength 413.0 nm, wavelength 535.0 nm, Au, Ag     

Optical detection of CA 15.3 breast cancer antigen using CdS quantum dot

The present study focus on optical sensing of breast cancer antigen 15.3 (CA 15.3) using cadmium sulphide quantum dot (CdS‐QD) in saline and serum samples spiked with antigen. The surface of CdS‐QD was modified by cysteamine capping followed by tagging of CA 15.3 antibody. The samples were characterised using UV‐visible absorption spectroscopy (UV‐VIS Spectroscopy), Fourier transform infrared spectroscopy (FTIR), high‐resolution transmission electron microscopy (HRTEM) attached with energy‐dispersive X‐ray spectroscopy, phase contrast inverted epi‐fluorescence microscopy and photoluminescence (PL) spectrophotometry (EDS). The CdS‐QD showed a mean diameter of 3.02 ± 0.6 nm. The complex formed after antigen‐antibody interaction resulted in distinguishable optical and fluorescence intensity with respect to varying concentration of antigen. The PL study revealed that CA 15.3 antibody labelled CdS QD can detect CA 15.3 tumour marker even at very low concentration of 0.002 KU/L with a constant response time of 15 min. This study clearly indicates that detection of CA 15.3 at low concentration is possible using surface modified CdS QD in serum samples and can find immense applications in biosensor development for detection of breast cancer marker similar to various automated detection kits available in market.Inspec keywords: semiconductor quantum dots, cadmium compounds, II‐VI semiconductors, wide band gap semiconductors, cancer, tumours, optical sensors, biosensors, biomedical equipment, visible spectra, ultraviolet spectra, Fourier transform infrared spectra, transmission electron microscopy, X‐ray chemical analysis, fluorescence, optical microscopy, photoluminescence, proteins, molecular biophysics, nanosensors, nanomedicine, nanoparticlesOther keywords: optical detection, CA 15.3 breast cancer antigen, optical sensing, cadmium sulphide quantum dot, saline samples, serum samples, cysteamine capping, CA 15.3 antibody, UV‐visible absorption spectroscopy, Fourier transform infrared spectroscopy, high‐resolution transmission electron microscopy, energy dispersive X‐ray spectroscopy, phase contrast inverted epifluorescence microscopy, photoluminescence spectrophotometry, antigen‐antibody interaction, fluorescence intensity, optical intensity, CA 15.3 tumour marker, surface modified CdS QD, biosensor development, time 15 min, CdS     

Green synthesis of silver nanoparticles using flower extract of Malva sylvestris and investigation of their antibacterial activity

High‐quality colloidal silver nanoparticles (AgNP) were synthesised via a green approach by using hydroalcoholic extracts of Malva sylvestris. Silver nitrate was used as a substrate ion while the plant extract successfully played the role of reducing and stabilising agents. The synthesised nanoparticles were carefully characterised by using transmission electron microscopy, atomic‐force microscopy, energy dispersive X‐ray spectroscopy, Fourier transform infrared spectroscopy and UV–vis spectroscopy. The maximum absorption wavelengths of the colloidal solutions synthesised using 70 and 96% ethanol and 100% methanol, as extraction solvents, were 430, 485 and 504 nm, respectively. Interestingly, the size distribution of nanoparticles depended on the used solvent. The best particle size distribution belonged to the nanoparticles synthesised by 70% ethanol extract, which was 20–40 nm. The antibacterial activity of the synthesised nanoparticles was studied on Escherichia coli, Staphylococcus aureus and Streptococcus pyogenes using disk diffusion, minimum inhibitory concentrations and minimum bactericidal concentrations assays. The best antibacterial activity obtained for the AgNPs produced by using 96% ethanolic extract.Inspec keywords: silver, nanoparticles, nanofabrication, antibacterial activity, colloids, particle size, transmission electron microscopy, atomic force microscopy, X‐ray chemical analysis, Fourier transform spectra, infrared spectra, ultraviolet spectra, visible spectra, microorganisms, nanomedicine, biomedical materialsOther keywords: Green synthesis, flower extract, Malva sylvestris, antibacterial activity, high‐quality colloidal silver nanoparticles, hydroalcoholic extracts, plant extract, reducing agents, stabilising agents, transmission electron microscopy, atomic‐force microscopy, energy dispersive X‐ray spectroscopy, Fourier transform infrared spectroscopy, UV– vis spectroscopy, colloidal solutions, particle size distribution, Escherichia coli, Staphylococcus aureus, Streptococcus pyogenes, disk diffusion, minimum inhibitory concentrations, minimum bactericidal concentrations assays, ethanolic extract, size 430 nm, size 485 nm, size 504 nm, size 20 nm to 40 nm, Ag     

Structural and optical investigation on the wings of Idea malabarica (Moore, 1877)

The nanostructures on the wings of Idea malabarica (Moore, 1877) were analysed using scanning electron microscopy, energy dispersive X‐ray spectroscopy, atomic force microscopy, Fourier transform‐infrared spectroscopy, and reflectance measurements. The chemical and morphological analyses revealed the chitin‐based intricate nanostructures. The influence of the nanostructures on the wetting characteristics of the wing was investigated using optical imaging. Applying the Maxwell‐Garnet approximation to the porosities within the nanostructures, the refractive indices, which relate the reflectance response, were estimated. It was concluded that the colour seen on the wings of the Idea malabarica originate from the nanostructural configurations of the chitin‐based structures and the embedded pigment.Inspec keywords: scanning electron microscopy, X‐ray chemical analysis, atomic force microscopy, Fourier transform infrared spectra, reflectivity, wetting, porosity, refractive index, nanostructured materials, nanobiotechnology, bio‐opticsOther keywords: Idea malabarica wings, scanning electron microscopy, energy dispersive X‐ray spectroscopy, atomic force microscopy, Fourier transform‐infrared spectroscopy, reflectance measurements, chitin‐based intricate nanostructures, wetting, Maxwell‐Garnet approximation, porosity, refractive indices     

Evaluation of antimicrobial activity of synthesised silver nanoparticles using Thymus kotschyanus aqueous extract

Development of a green chemistry process for the synthesis of silver nanoparticles (AgNPs) has become a focus of interest. Characteristics of AgNPs were determined using techniques, such as ultraviolet–visible spectroscopy (UV–vis), Fourier transform infrared (FTIR) analysis, scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy and X‐ray diffraction (XRD). The synthesised AgNPs using Thymus kotschyanus had the most growth inhibition against gram‐positive bacteria such as Staphylococcus aureus and Bacillus subtilise, while the growth inhibition of AgNPs at 1000–500 µg/ml occurred against Klebsiella pneumonia and at 1000–250 µg/ml of AgNPs was observed against E. coli. The UV–vis absorption spectra confirmed the formation of the AgNPs with the characteristic peak at 415 nm and SEM micrograph acknowledged spherical particles in a nanosize range. FTIR measured the possible biomolecules that are responsible for stabilisation of AgNPs. XRD analysis exhibited the crystalline nature of AgNPs and showed face‐centred cubic structure. The synthesised AgNPs revealed significant antibacterial activity against gram‐positive bacteria.Inspec keywords: visible spectra, microorganisms, ultraviolet spectra, biomedical materials, nanofabrication, nanoparticles, X‐ray diffraction, scanning electron microscopy, molecular biophysics, X‐ray chemical analysis, nanomedicine, silver, antibacterial activity, Fourier transform infrared spectraOther keywords: green chemistry process, ultraviolet–visible spectroscopy, gram‐positive bacteria, silver nanoparticles, Thymus kotschyanus aqueous extract, UV–vis spectroscopy, Fourier transform infrared spectroscopy, FTIR analysis, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, SEM micrograph, X‐ray diffraction, XRD, Staphylococcus aureus, Bacillus subtilise, Klebsiella pneumonia, E. coli, UV–vis absorption spectra, face‐centred cubic structure, antibacterial activity, antimicrobial activity, wavelength 415.0 nm, Ag     

Evaluating the effect of green synthesised copper oxide nanoparticles on oxidative stress and mitochondrial function using murine model

Green synthesis of metal nanoparticles (NPs) has now received the attention of researchers due to ease of preparation and its potential to overcome hazards of these chemicals for an eco‐friendly milieu. In this study, copper oxide (CuO) NPs were synthesised via Desmodium gangeticum aqueous root extract and standard chemical method, further characterised by UV–visible spectroscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, Thermogravimetric analysis and scanning electron microscopy. The nephrotoxicity of the NP obtained from two routes were compared and evaluated at subcellular level in Wistar rat, renal proximal epithelial cells (LLC PK1 cell lines) and isolated renal mitochondria. CuO NP synthesised by chemical route showed prominent nephrotoxicity measured via adverse cytotoxicity to LLC PK1 cells, elevated renal oxidative stress and damage to renal tissue (determined by impaired alanine transaminase, aspartate transaminase, urea, uric acid and creatinine in the blood). However, at the level of cell organelle, CuO NP from both routes are non‐toxic to mitochondrial functional activity. The authors’ finding suggests that CuO NP synthesised by chemical route may induce nephrotoxicity, but may be overcome by co‐administration of antioxidants, as it is not mito‐toxic.Inspec keywords: cellular biophysics, scanning electron microscopy, toxicology, nanomedicine, oxidation, nanoparticles, enzymes, blood, visible spectra, X‐ray diffraction, biochemistry, nanofabrication, antibacterial activity, ultraviolet spectra, copper compounds, Fourier transform infrared spectra, molecular biophysics, thermal analysis, biological tissuesOther keywords: green synthesised copper oxide nanoparticles, murine model, metal nanoparticles, chemicals, eco‐friendly milieu, copper oxide NPs, standard chemical method, X‐ray diffraction, scanning electron microscopy, subcellular level, renal proximal epithelial cells, LLC PK1 cell lines, renal mitochondria, renal tissue, cell organelle, mitochondrial functional activity, UV‐visible spectroscopy, Fourier transform infrared spectroscopy, nephrotoxicity, renal oxidative stress, Desmodium gangeticum aqueous root extract, thermogravimetric analysis, Wistar rat, cytotoxicity, impaired alanine transaminase, aspartate transaminase, urea, uric acid, creatinine, blood, CuO     

Characterisation of sol–gel method synthesised MgZnFe2 O4 nanoparticles and its cytotoxic effects on breast cancer cell line,MDA MB‐231 in vitro

In this study, nanocrystalline magnesium zinc ferrite nanoparticles were successfully prepared by a simple sol–gel method using copper nitrate and ferric nitrate as raw materials. The calcined samples were characterised by differential thermal analysis/thermogravimetric analysis, Fourier transform infrared spectroscopy and X‐ray diffraction. Transmission electron microscopy revealed that the average particle size of the calcined sample was in a range of 17–41 nm with an average of 29 nm and has spherical size. A cytotoxicity test was performed on human breast cancer cells (MDA MB‐231) and (MCF‐7) at various concentrations starting from (0 µg/ml) to (800 µg/ml). The sample possessed a mild toxic effect toward MDA MB‐231 and MCF‐7 after being examined with MTT (3‐[4, 5‐dimethylthiazol‐2‐yl]‐2, 5 diphenyltetrazolium bromide) assay for up to 72 h of incubation. Higher reduction of cells viability was observed as the concentration of sample was increased in MDA MB‐231 cell line than in MCF‐7. Therefore, further cytotoxicity tests were performed on MDA MB‐231 cell line.Inspec keywords: sol‐gel processing, nanoparticles, nanofabrication, magnesium compounds, zinc compounds, toxicology, biological organs, cancer, cellular biophysics, nanomedicine, calcination, differential thermal analysis, Fourier transform infrared spectra, X‐ray diffraction, transmission electron microscopy, particle size, organic compoundsOther keywords: sol‐gel method, cytotoxic effects, breast cancer cell line, MDA MB‐231 in vitro, nanocrystalline magnesium zinc ferrite nanoparticles, copper nitrate, ferric nitrate, raw materials, calcined samples, differential thermal analysis, thermogravimetric analysis, Fourier transform infrared spectroscopy, X‐ray diffraction, transmission electron microscopy, average particle size, cytotoxicity testing, human breast cancer cells, mild toxic effect, 3‐[4,5‐dimethylthiazol‐2‐yl]‐2,5 diphenyltetrazolium bromide) assay, cell viability, MCF‐7, MDA MB‐231 cell line, size 17 nm to 41 nm