聚苯胺/石墨烯/金复合材料的制备及超电容性能研究

以对苯二胺( p-PDA)为单体,氯金酸(HAuCl4)为氧化剂和Au源,氧化石墨烯(GO)为基底,通过原位聚合伴随Au纳米粒子生成的方法获得了聚苯胺/石墨烯/金(PpPD/GO/Au)的纳米复合材料.FESEM、FT-IR、XRD等测试表明,聚苯胺类衍生物、氧化石墨烯以及金纳米粒子三相在整个纳米复合材料中共存.材料的...     

Photo‐induced Leishmania DNA degradation by silver‐doped zinc oxide nanoparticle: an in‐vitro approach

Recently, the authors reported newly synthesised polyethylene glycol (PEG)ylated silver (9%)‐doped zinc oxide nanoparticle (doped semiconductor nanoparticle (DSN)) which has high potency for killing Leishmania tropica by producing reactive oxygen species on exposure to sunlight. The current report is focused on Leishmania DNA interaction and damage caused by the DSN. Here, we showed that the damage to Leishmania DNA was indirect, as the DSN was unable to interact with the DNA in intact Leishmania cell, indicating the incapability of PEGylated DSN to cross the nucleus barrier. The DNA damage was the result of high production of singlet oxygen on exposure to sunlight. The DNA damage was successfully prevented by singlet oxygen scavenger (sodium azide) confirming involvement of the highly energetic singlet oxygen in the DNA degradation process.Inspec keywords: silver, zinc compounds, nanoparticles, nanomedicine, DNA, microorganisms, cellular biophysics, biomedical engineeringOther keywords: photo‐induced Leishmania DNA degradation, PEGylated silver‐doped zinc oxide nanoparticle, Leishmania tropica, reactive oxygen species, sunlight, Leishmania DNA interaction, Leishmania cell, DNA damage, singlet oxygen scavenger, sodium azide, DNA degradation process, ZnO:Ag     

In‐vitro and in‐vivo evaluation of chitosan‐based thermosensitive gel containing lorazepam NLCs for the treatment of status epilepticus

The objective of this study was to develop an in‐situ gel containing lorazepam (LZM) loaded nanostructured lipid carriers (NLCs) for direct nose‐to‐brain delivery in order to increase drug therapeutic efficacy in the treatment of epilepsy. Accordingly, LZM loaded NLCs were formulated using emulsification solvent diffusion and evaporation method; then the effects of the formulation variables on different physicochemical characteristics of NLCs were investigated. Thermosensitive in‐situ gels containing LZM‐NLCs were prepared using a combination of chitosan and β‐glycerol phosphate (β‐GP). The anticonvulsant efficacy of LZM‐NLCs‐Gel was then examined using the pentylenetetrazole (PTZ) model. The optimised NLCs were spherical, showing the particle size of 71.70 ± 5.16 nm and the zeta potential of −20.06 ± 2.70 mV. The pH and gelation time for the chitosan solution with 15% (w/v) β‐GP were determined to be 7.12 ± 0.03 and 5.33 ± 0.58 min, respectively. The in‐vivo findings showed that compared with the control group and the group that received LZM‐Gel, the occurrence of PTZ‐induced seizures in the rats was significantly reduced by LZM‐NLCs‐Gel after intranasal administration. These results, therefore, suggested that the LZM‐NLCs‐Gel system could have potential applications for brain targeting through nasal route and might increase LZM therapeutic efficacy in the treatment of epilepsy.Inspec keywords: biomedical materials, nanomedicine, cellular biophysics, electrokinetic effects, drug delivery systems, nanoparticles, brain, pH, drugs, particle size, nanofabrication, medical disorders, polymer gelsOther keywords: evaporation method, β‐glycerol phosphate, β‐GP, optimised NLCs, received LZM‐Gel, LZM therapeutic efficacy, chitosan‐based thermosensitive gel, lorazepam NLCs, nose‐to‐brain delivery, drug therapeutic efficacy, emulsification solvent diffusion, in‐vivo evaluation, in‐vitro evaluation, LZM‐NLC‐gel system, status epilepticus treatment, lorazepam loaded nanostructured lipid carriers, epilepsy treatment, physicochemical characteristics, thermosensitive in‐situ gel, anticonvulsant efficacy, pentylenetetrazole model, particle size, zeta potential, pH, gelation time, chitosan solution, PTZ‐induced seizures, intranasal administration     

Preparation and photocatalytic performance of CuO/GO heterojunction nanocomposite

Recently, solar photocatalytic technology has proved to be an effective way to solve the problems of environmental pollution and energy shortage due to its green environmental protection and fast degradation rate. In this paper, a simple microwave hydrothermal method is used to prepare a novel CuO/GO heterojunction composite photocatalyst, and its chemical composition, microstructure, physicochemical properties, photothermal conversion, and photocatalytic properties are studied. The results show that the addition of GO in the CuO/GO nanocomposite photocatalyst not only effectively reduces the agglomeration of CuO nanoparticles but also makes it exhibit better photocatalytic activity than pure nano-CuO. The degradation rate of MB increased by 39.48% at 120 min of light, and as high as 94.1% at 180 min, mainly due to the construction of heterojunction at the interface and the synergistic promotion effect of light and heat. The internal mechanism of light and heat synergistic catalysis is revealed. This paper not only proposes a low-cost and efficient CuO/GO light-heat composite photocatalyst but also provides new ideas for subsequent researchers to design and prepare nanocomposite photocatalysts.

     

Formulation of garlic oil‐in‐water nanoemulsion: antimicrobial and physicochemical aspects

Despite the unique properties, application of garlic essential oil (GEO) is too limited in food and drugs, due to its low water solubility, very high volatility and unpleasant odour. In this work, a nanoemulsion containing GEO was formulated to cover and protect the volatile compounds of GEO. The encapsulation efficiency of formulated nanoemulsions was measured by gas chromatography and obtained encapsulation efficiency ranged from 91 to 77% for nanoemulsions containing 5–25% GEO, respectively. The 2,2‐diphenyl‐1‐picrylhydrazyl method for antioxidant activity measurement showed that free radical scavenging capacity of nanoemulsions intensified during storage time. The electrical conductivity of the samples was constant over storage time while linearly increased by raising the temperature. Thermogravimetric analysis was used to determine the thermal resistance of nanoemulsions and their ingredients. Interestingly, microbial tests cleared that the control nanoemulsion with a particle size below 100 nm (nanoemulsion without GEO) also showed antimicrobial activity. Disk diffusion method showed that pure GEO and also formulated nanoemulsions had a stronger effect against Gram‐positive bacterium (Staphylococcus aureus) than Gram‐negative bacterium (Escherichia coli).Inspec keywords: emulsions, nanostructured materials, antibacterial activity, microorganisms, electrical conductivity, thermal analysis, thermal resistance, oils, nanobiotechnology, food safety, cellular biophysicsOther keywords: garlic oil‐in‐water nanoemulsion, antimicrobial aspects, physicochemical aspects, garlic essential oil, GEO, volatile compounds, encapsulation efficiency, gas chromatography, 2,2‐diphenyl‐1‐picrylhydrazyl method, antioxidant activity measurement, free radical scavenging capacity, storage time, electrical conductivity, thermogravimetric analysis, thermal resistance, antimicrobial activity, disk diffusion method, Gram‐positive bacterium, Staphylococcus aureus, Gram‐negative bacterium, Escherichia coli     

CdO nanoparticles,c‐MWCNT nanoparticles and CdO nanoparticles/c‐MWCNT nanocomposite fibres: in vitro assessment of anti‐proliferative and apoptotic studies in HeLa cancer cell line

A simple ultrasonic assisted chemical technique was used to synthesise cadmium oxide (CdO) nanoparticles (NPs) and CdO NPs/c‐Multiwalled carbon nanotube (c‐MWCNT) nanocomposite fibres.To confirm the physio‐chemico properties and to analyse surface morphology of the obtained nanomaterials X‐Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM) were performed. To evaluate the anti‐cancer property of CdO NPs, c‐MWCNT NPs and CdO NPs/c‐MWCNT nanocomposite fibres, an anti‐proliferative assay test (Methylthiazolyl diphenyl‐ tetrazolium bromide ‐ MTT assay) were performed on HeLa cells which further estimated IC50 value (Least concentration of sample in which nearly 50% of cells remain alive) under in‐vitro conditions. On comparison, CdONPs/c‐MWCNT based system was found to be superior by achieving 52.3% cell viability with its minimal IC50 value of 31.2 μg/ml. Lastly, the CdO NPs based system was taken up for an apoptotic study using DNA fragmentation assay for estimating its ability to cleave the DNA of the HeLa cells into internucleosomal fragments using the agarose gel electrophoresis method. In conclusion, based on our observations, CdO NPs/c‐MWCNT hybrid based system can be further used for the development of efficient drug delivery and therapeutic systems.Inspec keywords: drug delivery systems, electrophoresis, oxidation, toxicology, DNA, nanoparticles, drugs, field emission electron microscopy, scanning electron microscopy, nanofabrication, surface morphology, cancer, X‐ray diffraction, nanomedicine, cellular biophysics, filled polymers, biomedical materials, molecular biophysics, biochemistry, Fourier transform infrared spectra, multi‐wall carbon nanotubesOther keywords: c‐MWCNT nanoparticles, apoptotic study, HeLa cancer cell line, cadmium oxide nanoparticles, c‐MWCNT NPs, anti‐proliferative assay test [methyl thiazolyl diphenyl‐tetrazolium bromide assay], human epithelioid cervix carcinoma cells, live cells, CdO NP‐based system, IC50 concentration, HeLa cell line, cell deaths, CdO‐C     

Co–Sn–Cu oxides/graphene nanocomposites as green catalysts for preparing 1,8‐dioxo‐octahydroxanthenes and apoptosis‐inducing agents in MCF‐7 human breast cancer cells

In this work, Co–Sn–Cu oxides/graphene nanocomposite, 30–40 ± 0.5 nm in size, was synthesized by solid‐state microwave irradiation. This method presents several advantages such as operational simplicity, fast, low cost, safe and energy efficient, and suitability for production of high purity of nanoparticles. Other advantages of this method are there is no need for the use of solvent, fuel, and surfactant. Co–Sn–Cu oxides/graphene nanocomposites have been characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometer, energy‐dispersive X–ray spectroscopy, and UV–Vis spectroscopy. The synthesized nanocomposites were used as novel highly efficient catalysts for the synthesis of 1,8‐dioxo‐octahydroxanthenes at room temperature. The catalysts are recoverable and can be reused for six runs without loss of their activity. Also, the obtained nanocomposites exhibited significant anticancer activity against breast cancer cells and they could induce apoptosis in cancer cells.     

In vitro mutagenic and anti‐mutagenic properties of green synthesised silver nanoparticles

This study is aimed at determining the mutagenic and anti‐mutagenic properties of silver nanoparticles (AgNPs) biosynthesised from Streptomyces griseorubens AU2. To the authors’ knowledge, this is the first study about the investigation of these properties for biogenic AgNPs bacterially synthesised. The mutagenic and anti‐mutagenic potencies were determined by the Ames Salmonella /microsome mutagenicity test using Salmonella typhimurium TA98 and TA100 strains. After determining the cytotoxic dose of green synthesised AgNPs against S. typhimurium TA98 and TA100 strains, subcytotoxic doses (250, 100 and 50 µg/plate) were used in the assays. Biogenic AgNPs at the tested concentrations exhibited no mutagenic effects in the mutagenicity test conducted with the test strains. Moderate anti‐mutagenic effects were observed at high test concentrations. The concentration of 250 µg/plate showed the strongest anti‐mutagenic activity on S. typhimurium TA98. The results did not indicate any mutagenic effect against either of the strains used for screening the mutagenicity of the biogenic AgNPs as they were found to be genotoxically safe. It can be concluded that biogenic AgNPs showed great anti‐mutagenic attributes, standing as a significant factor with respect to medical, pharmaceutical and cosmetic industries.Inspec keywords: biomedical materials, microorganisms, nanomedicine, nanoparticles, silver, toxicologyOther keywords: in vitro mutagenic properties, in vitro antimutagenic properties, green synthesised silver nanoparticles, Streptomyces griseorubens AU2, biogenic silver nanoparticle biosynthesis, microsome mutagenicity test, Salmonella typhimurium TA98 strains, Salmonella typhimurium TA100 strains, subcytotoxic doses, medical industries, pharmaceutical industries, cosmetic industries, Ag     

Investigating the in vitro photothermal effect of green synthesized apigenin‐coated gold nanoparticle on colorectal carcinoma

Applying toxic chemical to the synthesis of stable gold nanoparticles is one of the limitations of gold nanoparticles for therapeutic applications such as photothermal therapy. Plant compounds such as apigenin (API) with therapeutic potential can be applied in the synthesis of gold nanoparticles. API‐coated gold nanoparticles (Api@AuNPs) with an average size of 19.1 nm and a surface charge of −4.3 mV have been synthesized by a simple and efficient technique. The stability of Api@AuNPs in the biological environment was verified through UV‐Vis spectroscopy. Based on Raman and FTIR spectroscopy analysis, chemical binding of API on the surface of Api@AuNPs through hydroxyl and carbonyl functional groups was found to be the main reason for the stability of the Api@AuNPs in comparison with citrate‐coated gold nanoparticles (Cit@AuNPs). The synthesized Api@AuNPs do not cause major toxic effects up to 128 ppm. Api@AuNP‐mediated photothermal therapy leads to the indiscriminate eradication of almost half of both mouse fibroblastic (L929) and colorectal cancer (CT26) cells. Flow‐cytometry analysis revealed that the cell death mechanism is mainly apoptosis. In the apoptosis triggered cell death in photothermal treatment, Api@AuNPs are preferred over commonly used gold nanoparticles in photothermal treatments which mostly trigger the necrosis cell death pathway.     

TiO2 /chondroitin‐4‐sulphate nanocomposite coating on Ti–6Al–4V for implants and prostheses applications

Nano‐titania, chondroitin‐4‐sulphate, and titania/chondroitin‐4‐sulphate nanocomposite were separately deposited on Ti–6Al–4V alloys by repetitive spin coating. Surface characterisation techniques were used to find out the crystalline nature, chemical bonding, surface homogeneity, and elemental composition. Biological studies of nanocomposite‐coated alloys revealed the formation of stable hydroxyapatite (Ca/P = 1.678), superior corrosion resistance, and ∼12 mm zone of inhibition against Staphylococcus sp. However, the cell line studies revealed the better response on polymer‐coated alloy than the uncoated and composite‐coated alloy. It has been found that the nanocomposite coating can synergistically increase the thickness of the pre‐existing passive layer and thereby improve the corrosion resistance of Ti–6Al–4V implant in simulated body fluid. The nanocomposite coatings improved the corrosion resistance of the bare Ti–6Al–4V implant specimens by decreasing the i _corr. The formation of hydroxyapatite on nanocomposite‐coated alloy may have ability to inhibit the release of toxic substance to the adjacent tissues. In addition, the in vitro cell line study confers that the nanocomposite‐coated Ti–6Al–4V induces cell attachment and proliferation, and it eventually help to new bone cell formation than the uncoated one. Overall, this nanocomposite coating can be applied in orthopedic applications for effective biomimic bone regeneration.Inspec keywords: titanium compounds, nanocomposites, titanium alloys, aluminium alloys, vanadium alloys, nanomedicine, biomedical materials, prosthetics, X‐ray diffraction, Fourier transform spectra, infrared spectra, scanning electron microscopy, fluorescence, corrosion resistance, polymer films, calcium compounds, cellular biophysics, boneOther keywords: chondroitin‐4‐sulphate nanocomposite coating, implants, prostheses, nano‐titania, repetitive spin coating, surface characterisation, X‐ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, X‐ray fluorescence, TiAlV, TiO₂ , effective biomimic bone regeneration, orthopaedic applications, bone cell formation, osteoblast cells, cell proliferation, cell attachment, simulated body fluid solution, composite‐coated alloy, polymer‐coated alloy, Staphylococcus sp, corrosion resistance, hydroxyapatite, elemental composition, surface homogeneity, chemical bonding, crystalline nature     

Enhanced thermal resistance of GO/C/phenolic nanocomposite by introducing ZrB2 nanoparticles

The effectiveness of different additives on improving the thermal stabilities of phenolic composite was investigated by incorporating of graphene oxide sheets (GO) into the carbon/phenolic (PR), and then the ZrB₂ nanoparticles into the GO/PR composite. The GOs dissipate heat throughout the sample thereby reducing thermal gradients and the intensity of heating at the surface exposed to flame. Also, at higher exposure time, the resistance to oxidation of the nanocomposite begins taking advantage of the ongoing formation of an oxide coating layer (ZrO₂) on the exposed face. This protected the underlying unoxidized material from the structural damage caused by thermal shocks and high shear forces.     

High-performance gas sensor based on GO/In2O3 nanocomposite for ethanol detection

Journal of Materials Science: Materials in Electronics - Gas sensors are widely used because of their high sensitivity, low cost and simple fabrication. The development of high-performance ethanol...     

Factors affecting the antibacterial activity of chitosan‐silver nanocomposite

This study provides the optimum preparation parameters of chitosan‐silver nanoparticles composite (CSNC) with promising antibacterial activity against the most common bacterial infections found on burn wounds. CSNC was synthesised by simple green chemical reduction method with different preparation factors. Chitosan was used to reduce silver nitrate and stabilise silver nanoparticles in the medium. For this reason, spectroscopic and microscopic techniques as, ultraviolet‐visible Fourier transform infrared spectroscopy and transmission electron microscopy were used in the study of the molecular and morphological properties of the resultant composites. Furthermore, the composite was assessed in terms of Ag‐ions release by AAS and its efficacy as antibacterial material. As a result, CSNC showed stronger antibacterial effect than its individual components (chitosan and silver nitrate solutions) towards Gram‐positive (Staphylococcus aureus) and Gram‐negative (Pseudomonas aeruginosa and Escherichia coli) bacteria. CSNC prepared in this study showed highest inhibition percentage of bacterial growth up to 96% at concentration of 220 μg/ml.Inspec keywords: silver, nanocomposites, nanoparticles, filled polymers, biomedical materials, nanomedicine, antibacterial activity, wounds, reduction (chemical), ultraviolet spectra, visible spectra, Fourier transform spectra, infrared spectra, transmission electron microscopy, microorganisms, nanofabricationOther keywords: antibacterial activity, chitosan‐silver nanocomposite, optimum preparation parameters, chitosan‐silver nanoparticles composite, CSNC, bacterial infections, burn wounds, green chemical reduction method, ultraviolet‐visible Fourier transform infrared spectroscopy, transmission electron microscopy, molecular properties, morphological properties, Gram‐positive bacteria, Gram‐negative bacteria, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, bacterial growth, Ag     

In vitro evaluation of biodegradable nHAP‐Chitosan‐Gelatin‐based scaffold for tissue engineering application

The present study focuses on fabrication and characterisation of porous composite scaffold containing hydroxyapatite (HAP), chitosan, and gelatin with an average pore size of 250–1010 nm for improving wound repair and regeneration by Electrospinning method. From the results of X ‐Ray Diffraction (XRD) study, the peaks correspond to crystallographic structure of HAP powder. The presence of functional group bonds of HAP powder, Chitosan and scaffold was studied using Fourier Transform Infrared Spectroscopy (FTIR). The surface morphology of the scaffold was observed using Scanning Electron Microscope (SEM). The Bioactivity of the Nano composite scaffolds was studied using simulated body fluid solution at 37 ± 1°C. The biodegradability test was studied using Tris‐Buffer solution for the prepared nanocomposites [nano Chitosan, nano Chitosan gelatin, Nano based Hydroxyapatite Chitosan gelatin]. The cell migration and potential biocompatibility of nHAP‐chitosan‐gelatin scaffold was assessed via wound scratch assay and were compared to povedeen as control. Cytocompatibility evaluation for Vero Cells using wound scratch assay showed that the fabricated porous nanocomposite scaffold possess higher cell proliferation and growth than that of povedeen. Thus, the study showed that the developed nanocomposite scaffolds are potential candidates for regenerating damaged cell tissue in wound healing process.Inspec keywords: nanofabrication, tissue engineering, electrospinning, wounds, cellular biophysics, scanning electron microscopy, surface morphology, X‐ray diffraction, biomedical materials, nanomedicine, porosity, biodegradable materials, nanoporous materials, calcium compounds, gelatin, nanocomposites, Fourier transform infrared spectra, nanoparticles, precipitation (physical chemistry)Other keywords: average pore size, wound repair, crystallographic structure, HAP powder, functional group bonds, simulated body fluid solution, biodegradability test, Tris‐Buffer solution, cell migration, wound scratch assay, tissue engineering, electrospinning method, X‐ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, biocompatibility, cytocompatibility, porous nanocomposite scaffold, cell tissue, nHAP‐chitosan‐gelatin scaffold composites, wet chemical precipitation method, surface morphology, nanohydroxyapatite‐nanochitosan‐gelatin scaffold composites, cell proliferation, wound healing, (Ca₁₀ (PO₄)₆ (OH)₂)     

Alkaline treatment effect on the properties of in‐situ synthesised ZnO nanoparticles on cotton fabric

In this study, an in‐situ approach was used to synthesise zinc oxide nanoparticles on the surface of cotton fabric. The effect of alkaline pre‐ and after‐treatment and Zn²⁺ concentration was studied on the morphological, structural, thermal, photocatalytic, and antibacterial properties of loaded cotton fabrics. Scanning electron microscopy, energy dispersive X‐ray spectroscopy, X‐ray diffractometer, thermogravimetric analysis, and attenuated total reflection Fourier transform infrared spectrometer were used to characterise the properties of loaded cotton fabrics. Alkaline after‐treatment of cotton fabric presented more dispersed zinc oxide nanoparticles, and an increase in Zn²⁺ concentration led to form agglomerated nanoparticles on the surface of cotton fibres. The loaded cotton fabrics with zinc oxide nanoparticles presented an inhibition zone against Staphylococcus aureus and Escherichia coli. In addition, the stain of methylene blue on the surface of loaded samples was degraded after irradiated under visible light.Inspec keywords: nanofabrication, zinc compounds, II‐VI semiconductors, nanoparticles, nanomedicine, antibacterial activity, catalysis, photochemistry, cotton fabrics, scanning electron microscopy, X‐ray chemical analysis, X‐ray diffraction, thermal analysis, attenuated total reflection, Fourier transform infrared spectroscopy, microorganisms, materials preparationOther keywords: alkaline treatment effect, in‐situ synthesised ZnO nanoparticles, alkaline pretreatment, alkaline after‐treatment, Zn²⁺ concentration, morphological property, structural property, thermal property, photocatalytic property, antibacterial property, loaded cotton fabrics, scanning electron microscopy, energy dispersive X‐ray spectroscopy, X‐ray diffractometer, thermogravimetric analysis, attenuated total reflection Fourier transform infrared spectrometer, agglomerated nanoparticles, zinc oxide nanoparticles, inhibition zone, Staphylococcus aureus, Escherichia coli, methylene blue, visible light, ZnO     

Photothermal inactivation of methicillin‐resistant Staphylococcus aureus : anti‐biofilm mediated by a polypyrrole–carbon nanocomposite

Widespread resistance to antibiotics amongst pathogens has become a tremendous challenge of high morbidity and mortality rates which increases the needs to exploring novel methods of treatment. An efficient antimicrobial procedure to root out pathogenic bacteria is photothermal therapy. In this study, antimicrobial effects of a polypyrrole–carbon nanocomposite (PPy‐C) upon laser irradiation in order to destroy the pathogenic gram‐positive bacterium, methicillin‐resistant Staphylococcus aureus (MRSA) were assessed. The bacterial cells were incubated with 500, 750 and 1000 μg ml⁻¹ concentrations of PPy‐C and irradiated with an 808‐nm laser at a power density of 1.0 W cm⁻². To indicate the biocompatibility and toxic effect of the nanocomposite without and with laser irradiation, the authors counted the number of CFUs and compared it to an untreated sample. Antibacterial mechanisms of PPy‐C were assessed through temperature increment, reactive oxygen species production, and protein and DNA leakages. Photothermal heating assay showed that 26°C temperature increases in the presence of 1000 µg ml⁻¹ PPy‐C led to >98% killing of MRSA. Furthermore, 20 min radiation of near‐infrared light to PPy‐C in different concentrations indicated destruction and reduction in the MRSA biofilm formation. Therefore, PPy‐C was introduced as a photothermal absorber with a bactericidal effect in MRSA.Inspec keywords: laser applications in medicine, biomedical materials, DNA, nanofabrication, biochemistry, nanocomposites, microorganisms, nanomedicine, cellular biophysics, antibacterial activity, molecular biophysics, proteinsOther keywords: photothermal inactivation, staphylococcus aureus, anti‐biofilm, polypyrrole–carbon nanocomposite, widespread resistance, bacterial pathogens, high morbidity, mortality rates, efficient antimicrobial procedure, pathogenic bacteria, photothermal therapy, antimicrobial effects, PPy‐C, laser irradiation, pathogenic gram‐positive bacterium, bacterial cells, biocompatibility, toxic effect, reactive oxygen species production, photothermal heating assay, MRSA biofilm formation, photothermal absorber, bactericidal effect, methicillin‐resistance, temperature 26.0 degC, time 20.0 min     

Biogenic synthesis of biopolymer‐based Ag–Au bimetallic nanoparticle constructs and their anti‐proliferative assessment

This study reports an eco‐friendly‐based method for the preparation of biopolymer Ag–Au nanoparticles (NPs) by using gum kondagogu (GK; Cochlospermum gossypium), as both reducing and protecting agent. The formation of GK‐(Ag–Au) NPs was confirmed by UV‐absorption, fourier transformed infrared (FTIR), atomic force microscopy (AFM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The GK‐(Ag–Au) NPs were of 1–12 nm in size. The anti‐proliferative activity of nanoparticle constructs was assessed by MTT assay, confocal microscopy, flow cytometry and quantitative real‐time polymerase chain reaction (PCR) techniques. Expression studies revealed up‐regulation of p53, caspase‐3, caspase‐9, peroxisome proliferator‐activated receptors (PPAR) PPARa and PPARb, genes and down‐regulation of Bcl‐2 and Bcl‐x(K) genes, in B16F10 cells treated with GK‐(Ag–Au) NPs confirming the anti‐proliferative properties of the nanoparticles.Inspec keywords: nanomedicine, transmission electron microscopy, genetics, cellular biophysics, molecular biophysics, enzymes, nanofabrication, gold, silver, scanning electron microscopy, nanoparticles, Fourier transform infrared spectra, atomic force microscopy, biomedical materialsOther keywords: size 1.0 nm to 12.0 nm, Ag‐Au, anti‐proliferative assessment, eco‐friendly‐based method, anti‐proliferative activity, anti‐proliferative properties, biopolymer‐based Ag–Au bimetallic nanoparticle, Cochlospermum gossypium, gum kondagogu, biopolymer preparation, biogenic synthesis, UV‐absorption, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, atomic force microscopy, MTT assay, confocal microscopy, flow cytometry, caspase‐3, caspase‐9, peroxisome proliferator‐activated receptors, Bcl‐2 gene, Bcl‐x(K) gene, B16F10 cells     

Biologically‐synthesised ZnO/CuO/Ag nanocomposite using propolis extract and coated on the gauze for wound healing applications

Wound healing has long been recognised as a major clinical challenge for which stablishing more effective wound therapies is necessary. The generation of metallic nanocomposites using biological compounds is emerging as a new promising strategy for this purpose. In this study, four metallic nanoparticles (NPs) with propolis extract (Ext) and one without propolis including ZnO/Ext, ZnO/Ag/Ext, ZnO/CuO/Ext, ZnO/Ag/CuO/Ext and ZnO/W were prepared by microwave method and assessed for their wound healing activity on excision experimental model of wounds in rats. The developed nanocomposites have been characterised by physico‐chemical methods such as X‐ray diffraction, scanning electron microscopy, diffuse reflectance UV–vis spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis and Brunauer–Emmett–Teller analyses. The wounded animals treated with the NPs/Ext in five groups for 18 days. Every 6 days, for measuring wound closure rate, three samples of each group were examined for histopathological analysis. The prepared tissue sections were investigated by haematoxylin and Eosin stainings for the formation of epidermis, dermis and muscular and Masson''s trichrome staining for the formation of collagen fibres. These findings toughly support the probability of using this new ZnO/Ag/Ext materials dressing for a wound care performance with significant effect compared to other NPs.Inspec keywords: nanomedicine, X‐ray diffraction, II‐VI semiconductors, visible spectra, ultraviolet spectra, nanocomposites, biomedical materials, proteins, wounds, nanoparticles, scanning electron microscopy, nanofabrication, skin, zinc compounds, silver, antibacterial activity, Fourier transform infrared spectra, copper compounds, molecular biophysicsOther keywords: propolis, wound healing applications, effective wound, metallic nanocomposites, biological compounds, metallic nanoparticles, microwave method, wound healing activity, physico‐chemical methods, Fourier transform infrared spectroscopy, diffuse reflectance UV‐vis spectroscopy, Brunauer‐Emmett‐Teller analyses, wounded animals, wound closure rate, wound care performance, histopathological analysis, scanning electron microscopy, X‐ray diffraction, thermogravimetric analysis, haematoxylin, Eosin stainings, Masson trichrome, epidermis, muscular trichrome, collagen fibres, time 18.0 d, time 6.0 d, ZnO‐CuO‐Ag     

Assessment of in‐vivo biocompatibility evaluation of phytogenic gold nanoparticles on Wistar albino male rats

Nanomedicine is an interdisciplinary approach that involves toxicology and other medicinal applications. Gold nanoparticles (AuNPs) may serve as a promising model to address the size and shape‐dependent biological response because they show good biocompatibility. This study is to prepare phytosynthesis AuNPs from ten different Cassia sp. Among them, the aqueous leaf extract of C. roxburghii produced greater efficient and stable AuNPs. The AuNPs were optimised for different physicochemical conditions. Highly stable AuNPs were synthesised at pH 7.0, 37°C, 1.0 ml of C. roxburghii leaf extract and 1.0 mM concentration of HAuCl₄ with the particle size of ∼50 nm and these AuNPs were stable up to 12 months. To determine the safety profile of AuNPs in‐vivo, the nanoparticles were injected intravenously into male Wistar albino rats in varying dosages. The authors noticed no significant difference in body weights, haematological and biochemical parameters and the histopathological sections of all vital organs. Highest accumulation was seen in spleen and least in brain. The authors’ results show that the AuNPs were biocompatible and did not produce any adverse or abnormalities in‐vivo. The implications of the bioaccumulation of AuNPs need to be further studied to rule out any adverse effects on long‐term exposure.Inspec keywords: blood, nanoparticles, cellular biophysics, pH, nanomedicine, particle size, nanofabrication, gold, biomedical materialsOther keywords: in‐vivo biocompatibility evaluation, phytogenic gold nanoparticles, phytosynthesis AuNPs, physicochemical conditions, Wistar albino male rats, nanomedicine, Cassia sp., aqueous leaf extract, C. roxburghii leaf extract, particle size, bioaccumulation, temperature 37.0 degC, Au     

Biocompatibility enhancement of graphene oxide‐silver nanocomposite by functionalisation with polyvinylpyrrolidone

Several materials such as silver are used to enhance graphene oxide (GO) sheets antimicrobial activity. However, these toxic materials decrease its biocompatibility and hinder its usage in many biological applications. Therefore, there is an urgent need to develop nanocomposites that can preserve both the antimicrobial activity and biocompatibility simultaneously. This work highlights the importance of functionalisation of GO sheets using Polyvinylpyrrolidone (PVP) and decorating them with silver nanoparticles (AgNPs) in order to enhance their antimicrobial activity and biocompatibility at the same time. The structural and morphological characterisations were performed by UV‐Visible, Fourier transform infrared (FTIR), and Raman spectroscopic techniques, X‐ray diffraction (XRD), and high‐resolution transmission electron microscopy (HR‐TEM). The antimicrobial activities of the prepared samples against Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans were studied. The cytotoxicity of prepared materials was tested against BJ1 normal skin fibroblasts. The results indicated that the decoration with AgNPs showed a significant increase in the antimicrobial activity of GO and FGO sheets, and functionalisation of GO sheets and GO‐Ag nanocomposite with PVP improved the cell viability about 40 and 35%, respectively.Inspec keywords: biomedical materials, nanocomposites, visible spectra, ultraviolet spectra, X‐ray diffraction, cellular biophysics, nanoparticles, Raman spectra, filled polymers, transmission electron microscopy, silver, microorganisms, antibacterial activity, nanomedicine, nanofabrication, graphene compounds, toxicology, Fourier transform infrared spectraOther keywords: graphene oxide‐silver nanocomposite, polyvinylpyrrolidone, toxic materials, biocompatibility, antimicrobial activity, morphological characterisations, structural characterisations, UV‐visible spectra, Fourier transform infrared spectra, Raman spectra, X‐ray diffraction, high‐resolution transmission electron microscopy, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, cytotoxicity, BJ1 normal skin fibroblasts, cell viability, CO‐Ag