Antibacterial activity of carbon nanoparticles isolated from chimney soot

Carbon nanoparticles (CNPs) are isolated from chimney soot and characterised by various tools such as X‐ray diffraction, scanning electron microscopy, transmission electron microscopy and ultraviolet–visible spectroscopy. The X‐ray diffraction studies confirm the presence of C₆₀ nanoparticles in the isolated sample. The thermal properties of the prepared CNPs are recorded using thermogravimetric analysis and differential thermal analysis. The analysis of the antibacterial activity of the synthesised CNPs against selected Gram‐positive and Gram‐negative bacterial strains is also investigated. The systematic study confirms that CNPs collected from chimney soot exhibit good antibacterial potency against Staphylococcus aureus, Streptococcus pyogenes, Klebsiella pneumoniae, and Proteus mirabilis.Inspec keywords: ultraviolet spectra, scanning electron microscopy, visible spectra, differential thermal analysis, thermal analysis, antibacterial activity, nanoparticles, X‐ray diffraction, nanofabrication, transmission electron microscopy, carbonOther keywords: chimney soot, transmission electron microscopy, ultraviolet–visible spectroscopy, thermal properties, thermogravimetric analysis, differential thermal analysis, antibacterial activity, carbon nanoparticles, X‐ray diffraction study, gram‐positive bacterial strains, gram‐negative bacterial strains, antibacterial potency, scanning electron microscopy, C₆₀      

Inhibitory effect of magnetic iron‐oxide nanoparticles on the pattern of expression of lanosterol 14α ‐demethylase (ERG11) in fluconazole‐resistant colonising isolate of Candida albicans

Fluconazole‐resistant Candida albicans is a big scary reality. The authors assessed the antifungal effects of magnetic iron‐oxide nanoparticles on fluconazole‐resistant colonising isolate of C. albicans and determined the expression of ERG11 gene, protein sequence similarity and ergosterol content. C. albicans isolates were characterised and fluconazole resistance is recognised using World Health Organization''s WHONET software. Susceptibility testing of magnetic iron‐oxide nanoparticles against fluconazole‐resistant colonising isolate of C. albicans was performed according to Clinical and Laboratory Standards Institute guidelines. The expression patterns of ERG11 and protein sequence similarity were investigated. Ergosterol quantification has been used to gauge the antifungal activity of magnetic iron‐oxide nanoparticles. The findings indicated that 93% of C. albicans isolates were resistant to fluconazole. Magnetic iron‐oxide nanoparticles were presented activity against fluconazole‐resistant colonising isolate of C. albicans with minimum inhibitory concentration at 250–500 µg/ml. The expression level of ERG11 gene was downregulated in fluconazole‐resistant colonising isolate of C. albicans. The results revealed no differences in fluconazole‐resistant colonising isolate of C. albicans by comparison with ERG11 reference sequences. Moreover, significant reduction was noted in ergosterol content. The findings shed a novel light on the application of magnetic iron‐oxide nanoparticles in fighting against resistant C. albicans.Inspec keywords: microorganisms, biochemistry, molecular biophysics, antibacterial activity, iron compounds, proteins, cellular biophysics, nanoparticles, drugs, geneticsOther keywords: albicans isolates, magnetic iron‐oxide nanoparticles, fluconazole‐resistant colonising isolate, fluconazole resistance, ERG11, candida albicans, protein sequence similarity, ergosterol content, WHONET, ergosterol quantification, susceptibility testing, antifungal activity, gene expression     

Magnetic soy protein isolate–bovine serum albumin nanoparticles preparation as a carrier for inulinase immobilisation

Magnetic nanoparticles (NPs) were functionalised with soy protein isolate (SPI) and bovine serum albumin (BSA) for inulinase immobilisation. The results revealed the nanomagnetite size of about 50 nm with a polydispersity index (PDI) of 0.242. The average size of the SPI NPs prepared by using acetone was 80–90 nm (PDI, 0.277), and SPI–BSA NPs was 80–90 nm (PDI, 0.233), and their zeta potential was around −34 mV. The mean diameter of fabricated Fe₃ O₄ @SPI–BSA NPs was <120 nm (PDI, 0.187). Inulinase was covalently immobilised successfully through glutaraldehyde on Fe₃ O₄ @SPI–BSA NPs with 80% enzyme loading. Fourier transform infrared spectra, field emission scanning electron microscopy, and transmission electron microscopy images provided sufficient proof for enzyme immobilisation on the NPs. The immobilised inulinase showed maximal activity at 45°C, which was 5°C higher than the optimum temperature of the free enzyme. Also, the optimum pH of the immobilised enzyme was shifted from 6 to 5.5. Thermal stability of the enzyme was considerably increased to about 43% at 75°C, and K _m value was reduced to 25.4% after immobilisation. The half‐life of the enzyme increased about 5.13‐fold at 75°C as compared with the free form. Immobilised inulinase retained over 80% of its activity after ten cycles.Inspec keywords: magnetic particles, nanoparticles, proteins, molecular biophysics, nanofabrication, enzymes, Fourier transform spectra, infrared spectra, scanning electron microscopy, field emission ion microscopy, transmission electron microscopy, pH, biochemistry, nanobiotechnology, biomagnetism, electrokinetic effects, iron compoundsOther keywords: magnetic nanoparticles, soy protein isolate, bovine serum albumin, inulinase immobilisation, nanomagnetite, polydispersity index, SPI‐BSA NP, zeta potential, inulinase, glutaraldehyde, enzyme loading, Fourier transform infrared spectra, field emission scanning electron microscopy, transmission electron microscopy images, enzyme immobilisation, pH, size 80 nm to 90 nm, temperature 45 degC, temperature 75 degC, Fe₃ O₄      

Insights of CMNPs in water pollution control

The various toxic contaminants such as dyes, heavy metals, pesticides, rare‐earth elements, and hazardous chemicals are the major threats to all the flora and fauna. Owing to the harmful ill effects caused by the toxic contaminants, it is necessary to eliminate these compounds from the authors’ ecosystem. The chitosan magnetic nanomaterials (CMNPs) are one of the superior materials used in the wastewater treatment through various conventional technologies. The chitosan is a natural source obtained from the crustacean shells of crabs, prawns etc. The magnetic nanomaterial prepared by the reinforcement of chitosan is highly effective in the removal of heavy metals, dyes, organic matter, and harmful chemicals. It is used in various technologies such as adsorption, flocculation, immobilisation, photocatalytic technology, and bioremediation. This possesses unique surface and magnetic characteristics, Moreover, it is simple, economically feasible, and eco‐friendly material used efficiently in wastewater treatment. This review paper depicts the overview of CMNP in the industrial effluent treatment.Inspec keywords: effluents, adsorption, dyes, water pollution control, wastewater treatment, nanofabrication, nanoparticles, catalysis, industrial waste, photochemistry, flocculation, contamination, magnetic particlesOther keywords: CMNPs, water pollution control, toxic contaminants, dyes, heavy metals, pesticides, rare‐earth elements, hazardous chemicals, flora, fauna, chitosan magnetic nanomaterials, wastewater treatment, natural source, magnetic nanomaterial, organic matter, harmful chemicals, photocatalytic technology, magnetic characteristics, eco‐friendly material, industrial effluent treatment     

Studies on antimicrobial and wound healing applications of gauze coated with CHX–Ag hybrid NPs

In this study, chlorhexidine (CHX)–silver (Ag) hybrid nanoparticles (NPs) coated gauze was developed, and their bactericidal effect and in vivo wound healing capacities were tested. A new method was developed to synthesise the NPs, wherein Ag nitrate mixed with sodium (Na) metaphosphate and reduced using Na borohydride. Finally, CHX digluconate was added to form the hybrid NPs. To study the antibacterial efficacy of particles, the minimal inhibition concentration and biofilm degradation capacity against Gram‐positive and Gram‐negative bacteria was studied using Escherichia coli and Staphylococcus aureus. The results indicated that the NP inhibited biofilm formation and was bactericidal as well. The gauze was doped with NPs, and its wound healing property was evaluated using mice model. Results indicated that the wound healing process was fastened by using the NPs gauze doped with NPs without the administration of antibiotics.Inspec keywords: nanomedicine, nanoparticles, wounds, silver, cellular biophysics, biomedical materials, nanofabrication, microorganisms, antibacterial activityOther keywords: NPs gauze, antimicrobial wound healing applications, hybrid NPs, chlorhexidine–silver hybrid nanoparticles, CHX, coated gauze, bactericidal effect, minimal inhibition concentration, biofilm degradation capacity, Gram‐negative bacteria, wound healing property, wound healing process, in vivo wound healing capacities, Staphylococcus aureus, Escherichia coli, antibiotics administration, Na borohydride, Ag nitrate mixing, sodium metaphosphate, CHX digluconate, NP inhibited biofilm formation, Ag     

Antibacterial and anticancer activity of biosynthesised CuO nanoparticles

The present investigation aims for the synthesis of copper oxide nanoparticles (CuO NPs) using Nilgirianthus ciliatus plant extract. The obtained CuO NPs were characterised by X‐ray diffraction, Fourier transform infrared spectrum, ultraviolet–visible spectroscopy, photoluminescence, scanning electron microscopy and transmission electron microscopy analysis. Significant bacterial activity was manifested by CuO nanoparticles against both Gram‐positive (Staphylococcus aureus and Staphylococcus mutans) and Gram‐negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. The synthesised CuO NPs have good cytotoxicity against both human breast cancer cell line (MCF‐7) and lung cancer cell line (A549) with minimum cytotoxic effect on normal L929 (fibroblast) cell lines.Inspec keywords: microorganisms, ultraviolet spectra, nanomedicine, transmission electron microscopy, visible spectra, cellular biophysics, antibacterial activity, nanoparticles, X‐ray diffraction, lung, copper compounds, cancer, toxicology, biomedical materials, scanning electron microscopy, photoluminescence, Fourier transform infrared spectraOther keywords: antibacterial activity, anticancer activity, biosynthesised CuO nanoparticles, copper oxide nanoparticles, Nilgirianthus ciliatus plant, X‐ray diffraction, infrared spectrum, ultraviolet–visible spectroscopy, transmission electron microscopy analysis, bacterial activity, Gram‐negative bacteria, synthesised CuO NPs, human breast cancer cell line, Staphylococcus aureus, Staphylococcus mutans, CuO     

Structural and physicochemical properties of Rheum emodi mediated Mg(OH)2 nanoparticles and their antibacterial and cytotoxic potential

In the present investigation, Rheum emodi roots extract mediated magnesium hydroxide nanoparticles [Mg(OH)₂ NPs] through the bio‐inspired experimental technique were synthesised. Mg(OH)₂ NPs were characterised by using various characterisation techniques such as field emission scanning electron microscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and ultraviolet–visible spectroscopy. The formation of Mg(OH)₂ NPs was confirmed by X‐ray diffraction. The structural analysis confirmed the hexagonal crystal symmetry of Mg(OH)₂ NPs with space group P‐3m1 and space group no. 164 using the Rietveld refinement technique. TEM micrographs illustrated the nano‐size formation of Mg(OH)₂ NPs of spherical shape and size ∼14.86 nm. With the aid of FTIR data, plant metabolites such as anthraquinones have been identified as a stabilising and reducing agent for the synthesis of biogenic Mg(OH)₂ NPs. The synthesised Mg(OH)₂ NPs showed antimicrobial and cytotoxic potential against Gram‐negative and Gram‐positive bacteria such as Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 25923) and MDA‐MB‐231 human breast cancer cell lines.Inspec keywords: antibacterial activity, microorganisms, visible spectra, cancer, X‐ray diffraction, cellular biophysics, nanomedicine, ultraviolet spectra, nanoparticles, transmission electron microscopy, nanofabrication, field emission scanning electron microscopy, Fourier transform infrared spectra, particle size, magnesium compounds, space groups, toxicologyOther keywords: physicochemical properties, structural properties, Rheum emodi root extract mediated magnesium hydroxide nanoparticles, bio‐inspired experimental technique, field emission scanning electron microscopy, transmission electron microscopy, TEM, Fourier transform infrared spectroscopy, FTIR spectroscopy, ultraviolet‐visible spectroscopy, X‐ray diffraction, hexagonal crystal symmetry, space group P‐3m1, space group no. 164, Rietveld refinement technique, nanosize formation, plant metabolites, spherical shape, antibacterial potential, cytotoxic potential, reducing agent, anthraquinones, stabilising agent, Gram‐positive bacteria, Gram‐negative bacteria, Escherichia coli, Staphylococcus aureus, MDA‐MB‐231 human breast cancer cell lines, Mg(OH)₂      

Antimicrobial potential and in vitro cytotoxicity study of polyvinyl pyrollidone‐stabilised silver nanoparticles synthesised from Lysinibacillus boronitolerans

The main emphasis herein is on the eco‐friendly synthesis and assessment of the antimicrobial potential of silver nanoparticles (AgNPs) and a cytotoxicity study. Silver nanoparticles were synthesised by an extracellular method using bacterial supernatant. Biosynthesised silver nanoparticles were characterised by UV‐vis spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, dynamic light scattering, and zeta potential analysis. The synthesised silver nanoparticles exhibited a characteristic peak at 420 nm. TEM analysis depicted the spherical shape and approximately 20 nm size of nanoparticles. Silver nanoparticles carry a charge of −33.75 mV, which confirms their stability. Biogenic polyvinyl pyrrolidone‐coated AgNPs exhibited significant antimicrobial effects against all opportunistic pathogens (Gram‐positive and Gram‐negative bacteria, and fungi). Silver nanoparticles equally affect the growth of both Gram‐positive and Gram‐negative bacteria, with a maximum inhibition zone observed at 22 mm and a minimum at 13 mm against Pseudomonas aeruginosa and Fusarium graminearum, respectively. The minimum inhibitory concentration (MIC) of AgNPs against P. aeruginosa and Staphylococcus aureus was recorded at between 15 and 20 μg/ml. Synthesised nanoparticles exhibited a significant synergistic effect in combination with conventional antibiotics. Cytotoxicity estimates using C2C12 skeletal muscle cell line via 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) test and lactate dehydrogenase assay were directly related to the concentration of AgNPs and length of exposure. On the basis of the MTT test, the IC50 of AgNPs for the C2C12 cell line was approximately 5.45 μg/ml concentration after 4 h exposure.     

Biosynthesis of gold nanoparticles using fungus Trichoderma sp. WL‐Go and their catalysis in degradation of aromatic pollutants

An efficient green method of gold nanoparticles (AuNPs) biosynthesis was achieved by cell‐free extracts of fungus Trichoderma sp. WL‐Go. Based on UV–Vis spectra, AuNPs biosynthesised by cell‐free extracts with 90 mg/l protein exhibited a characteristic absorption band at 556 nm and was stable for 7 days. Transmission electron microscopy images revealed that the as‐synthesised AuNPs were spherical and pseudo‐spherical, and the average size was calculated to be 9.8 nm with a size range of 1–24 nm. The AuNPs illustrated their good catalytic activities for reduction of nitro‐aromatics (2‐nitrophenol, 3‐nitrophenol, 4‐nitrophenol, 2‐nitroaniline, 3‐nitroaniline) with catalytic rate constants of 7.4 × 10⁻³ s⁻¹, 10.3 × 10⁻³ s⁻¹, 4.9 × 10⁻³ s⁻¹, 5.8 × 10⁻³ s⁻¹, 15.0 × 10⁻³ s⁻¹, respectively. Meanwhile, the AuNPs also showed excellent catalytic performance in decolourisation of azo dyes with decolourisation efficiency from 82.2 to 97.5%. This study provided a green gentle method for AuNPs synthesis as well as exhibiting efficient catalytic capability for degradation of aromatic pollutants.Inspec keywords: catalysts, dyes, particle size, reduction (chemical), nanobiotechnology, nanofabrication, ultraviolet spectra, gold, transmission electron microscopy, nanoparticles, proteins, catalysis, visible spectra, pollution control, microorganismsOther keywords: nitro‐aromatics, catalytic rate constants, decolourisation efficiency, green gentle method, efficient green method, gold nanoparticles biosynthesis, cell‐free extracts, UV–Vis spectra, characteristic absorption band, transmission electron microscopy images, as‐synthesised AuNPs, catalytic performance, protein, catalytic activities, efficient catalytic capability, fungus Trichoderma sp. WL‐Go, aromatic pollutants degradation, 2‐nitrophenol, 3‐nitrophenol, 4‐nitrophenol, 2‐nitroaniline, 3‐nitroaniline, azo dye decolourisation, Au     

Induction of extrinsic and intrinsic apoptosis in cervical cancer cells by Momordica dioica mediated gold nanoparticles

Bio‐fabrication of gold nanoparticles (AuNPs) has several advantages like biocompatibility, less toxicity, and eco‐friendly in nature over their chemical and physical methods. Currently, the authors fabricated AuNPs using aqueous root extract of Momordica dioica (M. dioica) and explored their anticancer application with mechanistic approaches. Different biophysical techniques such as UV–visible spectroscopy, Fourier transform infrared, X‐ray diffraction, transmission electron microscopy, selected area electron diffraction, and dynamic light scattering were employed for AuNPs characterisation. The synthesised AuNPs were mono‐dispersed, crystalline in nature, anionic surface (−23.9 mV), and spherical particle of an average diameter of 9.4 nm. In addition, the AuNPs were stable in buffers solutions and also biocompatible towards normal human cells (human vascular endothelial cells and human lung cells). The AuNPs were exhibited anticancer activity against different cancer cell lines such as human breast cancer cells, human cervical cancer cells (HeLa) and human lung cancer cells. Further, the pro‐apoptotic genes such as Bcl₂ were down‐regulated and BAX, Caspase‐3, −8, and −9 were up‐regulated in HeLa cells as compared to untreated cells. Annexin‐V‐FITC assay results showed that the AuNPs were induced apoptosis by accumulation of intracellular reactive oxygen species. To their knowledge, this is the first report on the synthesis of bioactive metal nanoparticles from M. dioica and it may open up new avenues in therapeutic applications.Inspec keywords: nanomedicine, tumours, lung, visible spectra, drug delivery systems, cancer, transmission electron microscopy, biomedical materials, molecular biophysics, light scattering, toxicology, electron diffraction, X‐ray diffraction, ultraviolet spectra, biomembranes, drugs, gold, biochemistry, particle size, cellular biophysics, nanoparticles, nanofabrication, Fourier transform infrared spectraOther keywords: extrinsic apoptosis, intrinsic apoptosis, mediated gold nanoparticles, biofabrication, physical methods, biophysical techniques, UV‐visible spectroscopy, X‐ray diffraction, transmission electron microscopy, selected area electron diffraction, AuNPs characterisation, normal human cells, human vascular endothelial cells, cancer cell lines, human breast cancer cells, human cervical cancer cells, human lung cancer cells, HeLa cells, untreated cells, bioactive metal nanoparticles, Momordica dioica mediated gold nanoparticles, Fourier transform infrared spectra, proapoptotic genes, Bcl₂ , BAX, Caspase‐3, Caspase‐9, Caspase‐8, Annexin‐V‐FITC assay, intracellular reactive oxygen species, therapeutic applications, voltage ‐23.9 mV, size 9.4 nm, Au     

Process optimisation for green synthesis of ZnO nanoparticles and evaluation of its antimacrofouling activity

In recent years, considerable attention has been given to the plant‐mediated synthesis of nanoparticles because it is an eco‐friendly method compared to the synthesis by chemical route. This study aims to optimise the biosynthesis of zinc oxide nanoparticles (ZnO‐NPs) mediated by coconut water using response surface methodology (RSM). The effects of the individual variables (concentration of coconut water, temperature and time) and their interactions during the biosynthesis of ZnO‐NPs were determined by RSM employing Box–Behnken design. The variables selected were tested by a 17‐run experiment and quadratic model was used for the analysis of the results. The accuracy of the model was confirmed by the coefficient of determination (R ²) value of 0.9968. The significance of the regression model was found to be high which is validated by the low probability value of P  < 0.0001. The ZnO‐NPs thus synthesised was evaluated for its antimacrofouling activity against mollusks using in‐vitro foot‐adherence bioassay. The results demonstrated the potential of biosynthesised ZnO‐NPs in inhibiting fouling induced due to the test organisms.Inspec keywords: nanoparticles, antibacterial activity, response surface methodology, zinc compounds, regression analysis, design of experiments, biotechnologyOther keywords: plant‐mediated synthesis, eco‐friendly method, biosynthesis, zinc oxide nanoparticles, coconut water, response surface methodology, RSM, Box–Behnken design, quadratic model, regression model, antimacrofouling activity, biosynthesised ZnO‐NPs, process optimisation, green synthesis, ZnO nanoparticles     

Evaluation of the toxicities of silver and silver sulfide nanoparticles against Gram‐positive and Gram‐negative bacteria

In this study, the endogenous lipid signalling molecules, N ‐myristoylethanolamine, were explored as a capping agent to synthesise stable silver nanoparticles (AgNPs) and Ag sulphide NPs (Ag₂ S NPs). Sulphidation of the AgNPs abolishes the surface plasmon resonance (SPR) maximum of AgNPs at 415 nm with concomitant changes in the SPR, indicating the formation of Ag₂ S NPs. Transmission electron microscopy revealed that the AgNPs and Ag₂ S NPs are spherical in shape with a size of 5–30 and 8–30 nm, respectively. AgNPs and Ag₂ S NPs exhibit antimicrobial activity against Gram‐positive and Gram‐negative bacteria. The minimum inhibitory concentrations (MIC) of 25 and 50 μM for AgNPs and Ag₂ S NPs, respectively, were determined from resazurin microtitre plate assay. At or above MIC, both AgNPs and Ag₂ S NPs decrease the cell viability through the mechanism of membrane damage and generation of excess reactive oxygen species.Inspec keywords: cellular biophysics, biomembranes, transmission electron microscopy, nanomedicine, microorganisms, molecular biophysics, antibacterial activity, nanofabrication, silver, biomedical materials, surface plasmon resonance, nanoparticles, materials preparation, silver compounds, lipid bilayersOther keywords: Gram‐negative bacteria, Gram‐positive bacteria, endogenous lipid signalling molecules, N‐myristoylethanolamine, capping agent, silver nanoparticles, Ag sulphide NPs, sulphidation, surface plasmon resonance, concomitant changes, transmission electron microscopy, minimum inhibitory concentrations, resazurin microtitre plate assay, cell viability, membrane damage, reactive oxygen species, Ag toxicities, Ag, Ag₂ S     

Gold nanoparticles decorated reduced graphene oxide nanolabel for voltammetric immunosensing

This study describes the development and testing of a simple and novel enzyme‐free nanolabel for the detection and signal amplification in a sandwich immunoassay. Gold nanoparticles decorated reduced graphene oxide (rGOAu) was used as the nanolabel for the quantitative detection of human immunoglobulin G (HIgG). The rGOAu nanolabel was synthesised by one pot chemical reduction of graphene oxide and chloroauric acid using sodium borohydride. The pseudo‐peroxidase behaviour of rGOAu makes the nanolabel unique from other existing labels. The immunosensing platform was fabricated using self‐assembled monolayers of 11‐mercaptoundecanoic acid (11‐MUDA) on a gold disc electrode. The covalent immobilisation of antibody was achieved through the bonding of the carboxyl group of 11‐MUDA and the amino group of the antibody using chemical linkers [1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide] and N ‐hydroxysuccinimide. The fabricated immunosensor exhibited a linear range that included HIgG concentrations of 62.5–500 ng ml⁻¹. The sensor was also used for the testing of HIgG in the blood sample.Inspec keywords: proteins, nanomedicine, reduction (chemical), chemical sensors, nanofabrication, electrochemical sensors, voltammetry (chemical analysis), gold, oxidation, self‐assembly, monolayers, molecular biophysics, biochemistry, biosensors, nanoparticles, nanosensors, blood, grapheneOther keywords: gold nanoparticles, voltammetric immunosensing, enzyme‐free nanolabel, signal amplification, sandwich immunoassay, human immunoglobulin G, rGOAu nanolabel, chloroauric acid, sodium borohydride, 11‐mercaptoundecanoic acid, 11‐MUDA, gold disc electrode, chemical linkers, 1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide], HIgG concentrations, reduced graphene oxide nanolabel, quantitative HIgG detection, one pot chemical reduction, covalent antibody immobilisation, carboxyl group bonding, pseudo‐peroxidase behaviour, self‐assembled monolayers, N‐hydroxysuccinimide, immunosensor, blood sample, Au‐CO     

Synthesis and studies of bay‐substituted perylene diimide‐based D–A–D‐type SM acceptors for OSC and antimicrobial applications

In this study, the synthesis of a series of bay‐substituted donor–acceptor–donor (D–A–D) type perylene diimide derivatives (3a–3d) has been reported as an acceptor for the small‐molecule‐based organic solar cells (SM‐OSCs) by the Suzuki coupling method. It has been evaluated for the antimicrobial activity against some of the bacteria and fungi. The synthesised SMs were confirmed by Fourier transform‐infrared spectroscopy, nuclear magnetic resonance (NMR), and high resolution mass spectroscopy (HR‐MS). The SMs showed absorption up to 750 nm, which eventually reduced the optical band gap Egopt to  < 2 eV. SMs showed thermal stability up to 400 °C. In the SM‐OSC, the SMs showed a power conversion efficiency of  < 1% with the P3HT donor in bulk hetero‐junction device structure. Additionally, the new SMs showed antimicrobial activity against Gram‐negative bacteria such as Escherichia coli Gram‐positive bacteria such as Bacillus subtilis and antifungal activity against the Candida albicans, and Aspergillus niger. Cytotoxicity studies were carried out against the breast cancer cell lines MCF‐7 using MTT assay method. The results revealed that the SMs was able to inhibit the cancer cells. LD₅₀ s calculated for the SMs 3a–3d were between 200 and 400 µg/ml.Inspec keywords: antibacterial activity, solar cells, microorganisms, Fourier transform spectra, infrared spectra, nuclear magnetic resonance, photonic band gap, thermal stability, cellular biophysics, toxicology, cancer, nanomedicine, organic semiconductors, mass spectroscopy, biomedical materialsOther keywords: bay‐substituted perylene diimide‐based D‐A‐D‐type SM acceptors, donor‐acceptor‐donor type perylene diimide derivatives, small‐molecule‐based organic solar cells, SM‐OSC, Suzuki coupling method, antimicrobial activity, bacteria, fungi, Fourier transform infrared spectroscopy, NMR, HR‐MS, optical band gap, P3HT donor, bulk hetero‐junction device structure, Gram‐negative bacteria, Escherichia coli Gram‐positive bacteria, Bacillus subtilis, antifungal activity, Candida albicans, Aspergillus niger, cytotoxicity, breast cancer cell lines MCF‐7, MTT assay method, cancer cells, wavelength 750 nm, temperature 400 degC     

Autoclave‐assisted synthesis of AgNPs in Z. officinale extract and assessment of their cytotoxicity,antibacterial and antioxidant activities

In this study, the authors synthesised silver nanoparticles (AgNPs) using autoclave as a simple, unique and eco‐friendly approach. The effect of Zingiber officinale extract was evaluated as a reducing and stabiliser agent. According to transmission electron microscopy results, the AgNPs were in the spherical shape with a particle size of ∼17 nm. The biomedical properties of AgNPs as antibacterial agents and free radical scavenging activity were estimated. Synthesised AgNPs showed significant 1,1‐diphenyl‐2‐picryl‐hydrazyl free radical scavenging. Strong bactericidal activity was shown by the AgNPs on Gram‐positive and Gram‐negative bacteria. A maximum inhibition zone of ∼14 mm was obtained for epidermidis at a concentration of 60 μg/ml for sample fabricated at 24 h. The AgNPs also showed a significant cytotoxic effect against MCF‐7 breast cancer cell lines with an half maximal inhibitory concentration value of 62 μg/ml in 24 h by the MTT assay. It could be concluded that Z. officinale extract can be used effectively in the production of potential antioxidant and antimicrobial AgNPs for commercial application.Inspec keywords: nanoparticles, cancer, organic compounds, antibacterial activity, particle size, microorganisms, silver, visible spectra, ultraviolet spectra, biomedical materials, biochemistry, nanofabrication, free radicals, nanomedicine, toxicology, cellular biophysics, transmission electron microscopyOther keywords: unique approach, eco‐friendly approach, zingiber officinale, reducing agent, stabiliser agent, transmission electron microscopy results, antibacterial agents, free radical scavenging activity, synthesised AgNPs, 1‐diphenyl‐2‐picryl‐hydrazyl free radical scavenging, strong bactericidal activity, antimicrobial AgNPs, autoclave‐assisted synthesis, antioxidant activities, cytotoxic effect, silver nanoparticles, autoclave, time 24.0 hour     

Green synthesis,characterisation and biological evaluation of plant‐based silver nanoparticles using Quercus semecarpifolia Smith aqueous leaf extract

The development of reliable and green methods for the fabrication of metallic nanoparticles (NPs) has many advantages in the field of nanotechnology. In this direction, the present work describes an eco‐friendly and cost‐effective protocol for the production of silver NPs (AgNPs) using an aqueous extract of Quercus semecarpifolia leaves. Different techniques were carried out for the characterisation of the synthesised AgNPs. The ultraviolet–visible spectroscopic analysis showed the highest absorbance peak at 430 nm. The particle size and structure were confirmed by scanning electron microscopy as well as transmission electron microscopy (TEM) analysis. From TEM imaging, it was revealed that the formed particles were spherical with an average size of 20–50 nm. The crystalline nature of the NPs was determined by X‐ray powder diffraction patterns. Thermogravimetry and differential thermal analysis were also evaluated by a temperature increment from 100 to 1000°C. Bio‐inspired synthesis of AgNPs was performed for their pharmacological evaluation in relation to the activities of the crude methanolic, n ‐hexane, chloroform, ethyl acetate, and aqueous extracts. Good cytotoxic activity was exhibited by the green‐synthesised AgNPs (77%). Furthermore, the AgNPs were found to exhibit significant antioxidant activity at 300 μg/ml (82%). The AgNPs also exhibited good phytotoxic potential (75%).Inspec keywords: scanning electron microscopy, toxicology, visible spectra, particle size, nanofabrication, nanomedicine, transmission electron microscopy, silver, ultraviolet spectra, differential thermal analysis, nanoparticles, X‐ray diffraction, botany, biochemistry, cellular biophysicsOther keywords: green synthesis, biological evaluation, plant‐based silver nanoparticles, reliable methods, metallic nanoparticles, eco‐friendly cost‐effective protocol, silver NPs, ultraviolet–visible spectroscopic analysis, highest absorbance peak, particle size, structure, transmission electron microscopy analysis, TEM imaging, crystalline nature, X‐ray powder diffraction patterns, differential thermal analysis, pharmacological evaluation, aqueous extracts, good cytotoxic activity, significant antioxidant activity, AgNPs exhibited good phytotoxic potential, bio‐inspired synthesis, Quercus semecarpifolia Smith aqueous leaf extract, scanning electron microscopy, thermogravimetry, crude methanolic, n‐hexane, chloroform, ethyl acetate, phytotoxic potential, haemagglutination activity, size 20.0 nm to 50.0 nm, wavelength 430.0 nm, temperature 100 degC to 1000 degC, Ag     

Bio‐inspired synthesis of sulphur nanoparticles using leaf extract of four medicinal plants with special reference to their antibacterial activity

We report new, eco‐friendly and green method for the synthesis of sulphur nanoparticles using sodium polysulphide in the presence of leaf extracts of four different medicinal plants, which can be used for treatment of bacterial infections. Sodium polysulphide and acidic solution (H₂ SO₄) in the presence of plant leaf extract developed the yellowish precipitate in solution, which indicated the formation of sulphur nanoparticles. UV–Vis spectrophotometer analysis of reaction mixture showed absorbance spectra in the range of 292–296 nm, which is supposed to be specific for sulphur nanoparticles. Zeta potential study of sulphur nanoparticles synthesized from Catharanthus roseus showed more stability when compared with other medicinal plants. Sulphur nanoparticles synthesized from C. roseus were further characterized by XRD analysis, FTIR analysis, and TEM analysis. The biogenic sulphur nanoparticles were spherical, polydispersed with particle size of 70–80 nm. Evaluation of antibacterial study revealed that synthesized sulphur nanoparticles exhibited better bactericidal efficacy against common pathogenic bacteria Escherichia coli and Staphylococcus aureus with minimum inhibitory concentration of 200 μg/ml with significant activity used in combination with antibiotic. It can be concluded that the synthesized sulphur nanoparticles can be used as antibacterial agents after thorough experimental trials in animals.Inspec keywords: antibacterial activity, biomedical materials, nanoparticles, nanofabrication, sodium compounds, sulphur, ultraviolet spectra, visible spectra, Fourier transform infrared spectra, electrokinetic effects, transmission electron microscopy, X‐ray diffraction, microorganismsOther keywords: bio‐inspired synthesis, sulphur nanoparticles, leaf extract, medicinal plants, antibacterial activity, eco‐friendly, green synthesis, sodium polysulphide, bacterial infections, biological synthesis, UV–visible analysis, nanoparticle tracking analysis, zeta potential analysis, Fourier transform infrared spectroscopy, X‐ray diffraction analysis, transmission electron microscopy analysis, acidic solution, UV–Vis spectrophotometer analysis, pathogenic bacteria, Escherichia coli, Staphylococcus aureus, size 70 nm to 80 nm, wavelength 292 nm to 296 nm, S     

Effect of GNP functionalisation and multiple N ‐methylation of β ‐amyloid residue (32–37) on Gram‐positive bacterium

In the previous report, the authors showed the gold nanoparticle (GNP) functionalised multiple N ‐methylated fragments of the residue (32–37) of beta (β)‐amyloid protein (1–42), CGGIGLMVG and CGGGGGIGLMVG toward disruption of β ‐amyloid (1–42), the predominant component of senile plaques. Herein the in vitro antimicrobial activities of both normal and multiple N ‐methylated sequences of CGGIGLMVG and CGGGGGIGLMVG were screened and it was found that all the eight sequences including four (non‐functionalised with GNP) to possess activity against both Gram‐positive [Staphylococcus aureus (ATCC 43300) and Enterococcus faecalis (ATCC 5129)] and Gram‐negative [Escherichia coli (ATCC 35218), Pseudomonas aeruginosa (ATCC 27853) and Klebsiella pneumoniae (ATCC 700603)] bacteria. Among them, N ‐methylated sequences CGGIGLMVG and CGGGGGIGLMVG shown remarkable activity against Gram‐positive bacteria.Inspec keywords: microorganisms, gold, nanoparticles, nanomedicineOther keywords: GNP functionalisation, N‐methylation, β‐amyloid residue, Gram‐positive bacterium, gold nanoparticle functionalised multiple N‐methylated fragments, beta β‐amyloid protein, CGGGGGIGLMVG, Staphylococcus aureus, ATCC 43300, Enterococcus faecalis, ATCC 5129, Escherichia coli, ATCC 35218, Pseudomonas aeruginosa, ATCC 27853, Klebsiella pneumoniae, ATCC 700603, Au     

Phytosynthesis of Cu/rGO using Euphorbia cheiradenia Boiss extract and study of its ability in the reduction of organic dyes and 4‐nitrophenol in aqueous medium

For the first time, copper nanoparticles (Cu NPs) superficially deposited on reduced graphene oxide (rGO) using Euphorbia cheiradenia Boiss leaf aqueous media. A beneficial series of analytical methods was used to characterise E. cheiradenia Boiss leaf extract and involved nanostructures. The Cu/rGO nanocomposite (NC) obtained from the conversion of Cu²⁺ ions to Cu NPs and GO to rGO undergoes the plant extract and used as a heterogeneous and reusable nanocatalyst for the destruction of 4‐nitrophenol, rhodamine B, methylene blue, methyl orange and congo red using sodium borohydride at ambient temperature. In addition, Cu/rGO NC has reusability for many times in the reduction reactions with no decreasing of its catalytic capability.Inspec keywords: catalysts, nanofabrication, nanocomposites, dyes, nanoparticles, reduction (chemical), copper, graphene compoundsOther keywords: phytosynthesis, organic dyes, reusable nanocatalyst, Euphorbia cheiradenia Boiss extract, 4‐nitrophenol, nanoparticles, graphene oxide, nanocomposites, methylene blue, methyl orange, congo red, sodium borohydride, catalytic capability, Cu‐CO     

Green synthesis of nanosilver‐decorated graphene oxide sheets

A green facile method has been successfully used for the synthesis of graphene oxide sheets decorated with silver nanoparticles (rGO/AgNPs), employing graphite oxide as a precursor of graphene oxide (GO), AgNO₃ as a precursor of Ag nanoparticles (AgNPs), and geranium (Pelargonium graveolens) extract as reducing agent. Synthesis was accomplished using the weight ratios 1:1 and 1:3 GO/Ag, respectively. The synthesised nanocomposites were characterised by scanning electron microscopy, transmission electron microscopy, atomic force microscopy, X‐ray diffraction, UV‐visible spectroscopy, Raman spectroscopy, energy dispersive X‐ray spectroscopy and thermogravimetric analysis. The results show a more uniform and homogeneous distribution of AgNPs on the surface of the GO sheets with the weight ratio 1:1 in comparison with the ratio 1:3. This eco‐friendly method provides a rGO/AgNPs nanocomposite with promising applications, such as surface enhanced Raman scattering, catalysis, biomedical material and antibacterial agent.Inspec keywords: silver, nanoparticles, graphene, nanocomposites, scanning electron microscopy, transmission electron microscopy, atomic force microscopy, X‐ray diffraction, ultraviolet spectra, visible spectra, X‐ray chemical analysis, surface enhanced Raman scattering, catalysis, nanofabricationOther keywords: antibacterial agent, biomedical material, catalysis, surface enhanced Raman scattering, rGO‐AgNP nanocomposite, eco‐friendly method, homogeneous distribution, thermogravimetric analysis, energy dispersive X‐ray spectroscopy, Raman spectroscopy, UV‐visible spectroscopy, X‐ray diffraction, atomic force microscopy, transmission electron microscopy, scanning electron microscopy, nanocomposites, reducing agent, geranium, graphene oxide sheets, graphite oxide, silver nanoparticles, green facile method