Synthesis, characterization and protection effect of black rice anthocyanins nano-composite against hepatotoxicity induced by methotrexate in rats

Abstract The present study aimed to investigate the beneficial of prepared black rice anthocyanins nano-composite (An-AgNps) against hepatotoxicity induced by methotrexate (MTX) in rats. Anthocyanins nano-composite was prepared by silver as the metallic ion reduction and were characterized by IR and SEM. The rats in our experiment were divided into five groups. Serum lipid profile, serum transaminases (ALT and AST), ALP, LDH, TBA, GSH and SOD were examined. The results show that SEM of An-AgNps has average particle size from 70 to 130nm. In the group treated with MTX; TC, TG, LDL-c, ALT, AST, ALP, LDH and TBA levels were significantly (P0.05) increased than NC, while, HDL-c, SOD and GSH levels were significantly (P0.05) decreased. On the other hand, An-AgNps + MTX treated groups were reversed the levels of all biomarkers similar to NC. In conclusion, the results show that An-AgNps has a protective effect on MTX-induced hepatotoxicity and oxidative stress.

Resumo O presente estudo teve como objetivo investigar o benefício de nanocompósito de antocianinas de arroz preto preparado (An-AgNps) contra a hepatotoxicidade induzida por metotrexato (MTX) em ratos. O nanocompósito de antocianinas foi preparado a partir da prata por meio da redução do íon metálico e caracterizado por IR e SEM. Os ratos em nosso experimento foram divididos em cinco grupos, e foram examinados o perfil lipídico sérico, as transaminases séricas (ALT e AST), ALP, LDH, TBA, GSH e SOD. Os resultados mostram que SEM de An-AgNps tem tamanho médio de partícula de 70 a 130 nm. No grupo tratado com MTX, os níveis de TC, TG, LDL-c, ALT, AST, ALP, LDH e TBA aumentaram significativamente (P 0,05) do que NC, enquanto os níveis de HDL-c, SOD e GSH diminuíram significativamente (P 0,05). Por outro lado, nos grupos tratados com An-AgNps + MTX, foram revertidos os níveis de todos os biomarcadores semelhantes ao NC. Em conclusão, os resultados mostram que o An-AgNps tem um efeito protetor contra a hepatotoxicidade induzida pelo MTX e o estresse oxidativo.

The effect of curing modes and times of Third-Generation led LCU on the mechanical properties of nanocomposites / Efecto del modo y tiempo de fotocurado de la lámpara LCU Led de tercera generación en las propiedades mecánicas de los nanocompuestos

Abstract This study evaluates the effect of curing modes and times on the mechanical properties of nanocomposites. Two nanocomposite resins were investigated: suprananohybrid (Estelite Posterior Quick; EP) and nanohybrid (Solare X; SX). They were polymerized with a light-emitting diode light-curing units (LED LCU, Valo) as follows: standard mode for 20s (ST20), high power mode for 12s (HP12), high power mode for 20s (HP20), extra power mode for 6s (XP6), and extra power mode for 20s (XP20). For Vickers microhardness (HV), disc-shaped specimens were fabricated (n=10). For the three-point bending test, bar-shaped specimens were fabricated (n=10). Flexural strength and resilience modulus were calculated. The fractured surfaces and specimen surfaces of composites were observed using scanning electron microscopy. The data were analyzed with repeated measures ANOVA, two-way variance, and Bonferroni tests (p<0.05). On the top and bottom surfaces of the EP nanocomposite resin, ST20 and HP12 revealed statistically higher HV than with XP6. Moreover, HP20 and XP20 had statistically higher HV than HP12 and XP6. For the SX nanocomposite resin, HP20 had statistically higher HV than HP12. For EP and SX, there were no significant differences in flexural strength and resilience modulus regarding the curing modes and times. Furthermore, SX demonstrated lower mechanical properties than EP. Scanning electron microscopy indicated that both nanocomposites had similar surface appearances. However, with all curing modes and times, SX exhibited layered fractures and more crack formations than EP. Different curing modes and times could influence the microhardness of nanocomposites.

Resumen Este estudio evalúa el efecto del modo y tiempo de fotocurado sobre las propiedades mecánicas de los nanocompuestos. Se investigaron dos resinas nanocompuestas: supra-nanohíbrida (Estelite Posterior Quick; EP) y nanohíbrida (Solare X; SX). Se polimerizaron con unidades de fotopolimerización de diodos emisores de luz (LED LCU, Valo) de la siguiente manera: modo estándar durante 20s (ST20), modo de alta potencia durante 12s (HP12), modo de alta potencia durante 20s (HP20) , modo extra power durante 6s (XP6) y modo extra power durante 20s (XP20). Para la microdureza Vickers (HV), se fabricaron especímenes en forma de disco (n=10). Para el ensayo de flexión de tres puntos, se fabricaron probetas en forma de barra (n=10). Se calcularon la resistencia a la flexión y el módulo de resistencia. Las superficies fracturadas se observaron mediante microscopía electrónica de barrido. Los datos se analizaron con ANOVA varianza de dos vías y pruebas de Bonferroni (p<0,05). En las superficies superior e inferior de la resina nanocompuesta EP, ST20 y HP12 revelaron un HV estadísticamente mayor que con XP6. Además, HP20 y XP20 tenían un HV estadísticamente más alto que HP12 y XP6. Para la resina nanocompuesta SX, HP20 tenía un HV estadísticamente más alto que HP12. Para EP y SX, no hubo diferencias significativas en la resistencia a la flexión y el módulo de resistencia con respecto al modo y tiempo de fotocurado. Además, SX demostró propiedades mecánicas inferiores que EP. La microscopía electrónica de barrido indicó que ambos nanocompuestos son similares en la superficie. Sin embargo, SX exhibió fracturas en capas y más formaciones de grietas que EP. Diferentes modos y tiempos de fotocurado podrían influir en la microdureza de los nanocompuestos.

Photocatalytic destruction of Escherichia coli in water over rGO/TiO2 nanocomposites

In the present study, Graphene-TiO2 catalysts are prepared by solvothermal method with varied graphene concentrations (1%, 2.5% and 5%). The prepared nanocomposites were characterized by FTIR, Raman and TEM. The photocatalytic activity towards the destruction of Escherichia coli in water under UV and UV-visible irradiations were studied. Graphene-TiO2 nano composite destructs the bacteria significantly at higher rates than unmodified TiO2 and graphene. The results indicates that, at the beginning, the inactivation of E. coli cells is more due to the generation of reactive oxygen species (ROS) like, OH, H2O2, and O2– . Among all samples, the nano composite containing 2.5 wt.% of graphene exhibits a complete E. coli destruction in a minimum irradiation time of 15 and 20 min under UV–Visible and UV light irradiation respectively. The high photocatalytic activity is achieved with the optimum loading concentration of 2.5 wt. % graphene on titania

Clinical Effectiveness of Composite Resin Bonded with Universal Adhesive for the Restoration of Non-Carious Cervical Lesions Using Air Abrasion: A Randomised Controlled Trial

ABSTRACT @#Restorative treatment is very challenging for non-carious cervical lesions (NCCLs) due to functional and structural complexities. The purpose of this randomised controlled trial (RCT) was to evaluate the clinical performance of nanocomposite restorations bonded using universal adhesive in self-etch mode with and without air abrasive surface treatment for NCCLs. A total of 70 NCCLs, from a group of consenting patients who fulfilled the inclusion criteria, were recruited for the study. The study was carried out following CONSORT guidelines. Block randomisation was done for equal allocation of lesions into; Group 1 (surface treatment with alumina air abrasion) and Group 2 (control group without mechanical surface treatment). The lesions were restored with nanocomposite using a universal bonding agent in self-etch mode. The clinical performance of the restorations was evaluated by two examiners using modified United States Public Health Service (USPHS) criteria at baseline, 3 months, 6 months and 12 months. A Chi-square test was performed for inter-group comparison. Cochran’s Q test and Dunn’s post hoc analysis were used for intra-group comparison. The inter-group comparison revealed no statistically significant difference between the experimental and control group for all the parameters assessed. With the intra-group analysis, it was found that there was a significant decrease in the performance of the restorations concerning marginal staining, marginal adaptation and surface texture during the evaluation period (p < 0.05). However, all of them demonstrated clinically acceptable performance. According to the results of this RCT, it was concluded that airborne particle abrasion of NCCLs did not improve the clinical performance of nanocomposite resin bonded using universal adhesive.

Evaluation of antibacterial properties and shear bond strength of orthodontic composites containing silver nanoparticles, titanium dioxide nanoparticles and fluoride: An in vitro study

ABSTRACT Objective: The study aimed at determining the antibacterial properties of composites containing silver nanoparticles (Ag NPs) or titanium dioxide nanoparticles (TiO2 NPs), and a fluoride-releasing composite against Streptococcus mutans and Lactobacillus acidophilus, and to evaluate the effect on shear bond strength (SBS) of nanoparticles-modified composites. Materials and Methods: An orthodontic composite was modified by adding 1% w/w Ag NPs or 1% w/w TiO2 NPs. Composite discs were prepared to evaluate the antibacterial properties of these modified composites against Streptococcus mutans and Lactobacillus acidophilus, using three different antibacterial tests, namely: Disk agar diffusion test, Biofilm inhibition test and eluted component test. For evaluating the shear bond strength, 80 extracted premolars were collected and divided into four groups (n=20 each), which were bonded with stainless steel preadjusted Edgewise brackets, by using these modified composites. Their SBS was then compared with that of the control group, using a universal testing machine. Results: Composite discs containing nanoparticles and fluoride were capable of producing growth inhibition zones for all bacterial types. Results of the biofilm inhibition test showed that all the study groups inhibited the bacterial count, in comparison to the control group. A significant difference of SBS was observed between all groups. Conclusion: The antibacterial activity of orthodontic composites modified with Ag and TiO2 nanoparticles was significant, compared with conventional and fluoride-containing composites. The control group showed the highest SBS, followed by fluoride, titanium, and silver groups, with statistically significant difference in mean SBS values among all groups.

RESUMO Objetivo: O objetivo do presente estudo foi determinar a eficácia das propriedades antibacterianas de compósitos contendo nanopartículas de prata (Ag NPs) ou nanopartículas de dióxido de titânio (TiO2 NPs) e de um compósito com liberação de flúor, contra as bactérias Streptococcus mutans e Lactobacillus acidophilus e, também, avaliar o efeito na resistência ao cisalhamento (RC) desses compósitos modificados com nanopartículas. Métodos: Os compósitos ortodônticos foram modificados pela adição de 1% p/p de Ag NPs e 1% p/p de TiO2 NPs. Discos de compósito foram preparados para avaliar as propriedades antibacterianas desses grupos contra as bactérias Streptococcus mutans e Lactobacillus acidophilus, usando três testes antibacterianos diferentes: teste de disco-difusão em ágar, teste de inibição da formação de biofilme e teste de componentes eluídos. Para avaliar a resistência ao cisalhamento dos compósitos, 80 pré-molares extraídos foram coletados e divididos em quatro grupos, contendo 20 dentes cada. Foram utilizados braquetes Edgewise pré-ajustados de aço inoxidável para colagem nos dentes usando as resinas modificadas. A RC desses compósitos modificados foi comparada à dos grupos controle, usando uma máquina universal de testes. Resultados: Os discos de compósito contendo as nanopartículas e flúor foram capazes de produzir halos de inibição de crescimento para todos os tipos de bactérias. Os resultados do teste de inibição do biofilme mostraram que houve uma redução na contagem de bactérias em relação ao grupo controle. Diferenças significativas na RC foram observadas entre todos os grupos. Conclusão: A atividade antibacteriana dos compósitos ortodônticos modificados com nanopartículas de Ag e TiO2 foi significativa, quando comparada ao compósito convencional e ao compósito com flúor. O grupo controle apresentou a maior RC, seguido pelos grupos Flúor, Titânio e Prata, com diferença estatisticamente significativa nos valores médios da RC entre todos os grupos.

Biosynthesis of Graphene and Investigation of Antibacterial Activity of Graphene-parthenium hysterophorous Nanocomposite

Abstract There is a great interest to use carbon-based material like graphene and graphene oxide in biomedical applications due to its flexibility to be functionalized with bio-active molecules. Herein, graphene and graphene-based nanocomposites were biosynthesized by liquid-phase exfoliation of graphite using aqueous extract of Parthenium hysterophorous (P-H) as a surfactant. A set of five thin film samples of graphene was prepared from graphene suspension by vacuum filtration method. Samples were characterized by UV-vis spectroscopy, Raman spectroscopy, SEM, and XRD, which revealed successful synthesis of graphene. Graphene/P-H(G/P-H) nanocomposites comprising varied ratios of graphene and P-H were prepared and their antibacterial activity was investigated by agar well diffusion method. The experimental results indicated that G/P-H nanocomposite have higher antibacterial activity than graphene alone, and bioactivity of G/P-H nanocomposite was found to be controlled by the fraction of graphene in the composite.

Avaliação da atividade antimicrobiana de biomateriais nanocompósitos de poliamida 6 com nanopartículas de trimetafosfato decoradas com nanopartícula de prata / Evaluation of the antimicrobial activity of polyamide 6 nanocomposite biomaterials with trimetaphosphate nanoparticles decorated with silver nanoparticles

O uso de novos materiais nanocompósitos para fabricação de dispositivos protéticos, matrizes para preenchimento de defeitos ósseos, proteção do tecido pulpar de dentes e túbulos dentinários expostos pode colaborar significativamente na qualidade de vida da população. Objetivo: Realizar o processamento da matriz polimérica de poliamida-6 (P6) impregnada com nanopartículas de trimetafosfato (TMP) e nanopartícula de prata (AgNP), avaliar a atividade antimicrobiana contra Streptococcus mutans e Candida albicans e a liberação de TMP e Ag+ . Métodos: Foi determinado a concentração inibitória mínima (CIM) da AgNP com ou sem a presença da NH3 para S. mutans e C. albicans. Em seguida, realizado a síntese e caracterização dos nanocompósios (P6, P6-2,5, 5 e 10%TMP associado ou não a AgNP), quantificação das unidades formadoras de colônia (UFC), determinação do halo de inibição e quantificação de TMP e Ag+ liberados durante 1, 2, 3, 4, 5, 10, 12, 14, 16, 18, 20 e 24 horas em água deionizada. Os dados foram submetidos à análise de variância bidirecional, seguida do teste de Fisher LSD (p< 0,05). Resultados: A CIM para C. albicans foi de 9,40 mg/mL com ou sem a presença da NH3 e para o S. mutans foi de 601,9 mg/mL com NH3 e 300,9 mg/mL sem NH3. Nos testes de caracterização foi possível incorporar a P6 com TMP sem alterar suas propriedades. A maior quantidade de Ag+ liberada ocorreu nas primeiras três hora para todos os grupos decorados com AgNP. Houve liberação de TMP nas primeira três horas para os grupos P6-5%TMP e P6-10%TMP e para as demais membranas não foram detectadas liberações. No ensaio de difusão em ágar os halos formados para C. albicans e S. mutans mostraram ação da AgNP para ambos os microrganismos. Os grupos P6-Ag2,5%TMP e P6-Ag-5%TMP com AgNP apresentam maior redução de UFC para S. mutans quando comparado aos demais grupos, com maior redução no tempo de 18 horas. Para C. albicans todos os grupos apresentaram redução na UFC quando comparado ao controle, sem diferença estatística entre os mesmo. Conclusão: Foi possível desenvolver um matriz polimérica de P6 impregnada com TMP e AgNP com ação antimicrobiana contra os microrganismos testados(AU)

The use of new nanocomposite materials for the manufacture of prosthetic devices, matrices for filling bone defects, protection of the pulp tissue of exposed teeth and dentinal tubules can significantly contribute to the quality of life of the population. Objective: To perform the processing of the polymeric matrix of polyamide. 6 (P6) impregnated with trimetaphosphate nanoparticles (TMP) and silver nanoparticles (AgNP), evaluate the antimicrobial activity against Streptococcus mutans and Candida albicans and the release of TMP and Ag +. Methods: The minimum inhibitory concentration (MIC) of AgNP was determined with or without the presence of NH3 for S. mutans and C. albicans. Then, the synthesis and characterization of the nanocomposites (P6, P6-2.5, 5 and 10% TMP associated or not with AgNP), quantification of colony forming units (CFU), determination of the inhibition halo and quantification of TMP and Ag + released during 1, 2, 3, 4, 5, 10, 12, 14, 16, 18, 20 and 24 hours in deionized water. The data were submitted to bidirectional analysis of variance, followed by the Fisher LSD test (p < 0.05). Results: The MIC for C. albicans was 9.40 mg / mL with or without the presence of NH3 and for S. mutans it was 601.9 mg / mL with NH3 and 300.9 mg / mL without NH3. In the characterization tests it was possible to incorporate the P6 with TMP without changing its properties. The highest amount of Ag + released occurred in the first three hours for all groups decorated with AgNP. There was TMP release in the first three hours for the P6-5% TMP and P6-10% TMP groups and for the other membranes, no releases were detected. In the agar diffusion assay, halos formed for C. albicans and S. mutans showed AgNP action for both microorganisms. The P6-Ag-2.5% TMP and P6-Ag-5% TMP groups with AgNP show a greater reduction in CFU for S. mutans when compared to the other groups, with a greater reduction in the time of 18 hours. For C. albicans, all groups showed a reduction in CFU when compared to the control, with no statistical difference between them. Conclusion: It was possible to develop a polymeric matrix of P6 impregnated with TMP and AgNP with antimicrobial action against the microorganisms tested(AU)

Preparation and applications of the polymeric micelle/hydrogel nanocomposites as biomaterials / 生物医学工程学杂志

Polymeric hydrogels have been widely researched as drug delivery systems, wound dressings and tissue engineering scaffolds due to their unique properties such as good biocompatibility, shaping ability and similar properties to extracellular matrix. However, further development of conventional hydrogels for biomedical applications is still limited by their poor mechanical properties and self-healing properties. Currently, nanocomposite hydrogels with excellent properties and customized functions can be obtained by introducing nanoparticles into their network, and different types of nanoparticles, including carbon-based, polymer-based, inorganic-based and metal-based nanoparticle, are commonly used. Nanocomposite hydrogels incorporated with polymeric micelles can not only enhance the mechanical properties, self-healing properties and chemical properties of hydrogels, but also improve the

In situ green synthesis of antibacterial copper nanocomposite cotton fabrics using Achyranthes aspera leaf extract

Nanomaterials are finding the diversity of application at the leading edge in emerging field of nanotechnology. Coppernanoparticles (CuNPs) were in situ generated on the surface of cotton fabrics, using Achyranthes aspera leaf extract byenvironmentally benign green synthesis. The structural and morphological properties of synthesized nanocompositecotton fabrics (NCFs) were characterized by different spectral studies such as Fourier-transformation infrared (FTIR),scanning electron microscopy (SEM) coupled with energy-dispersive X-ray primary and derivative thermogravimetric(TG-DTG), differential scanning calorimetry (DSC), and X-ray diffractometer (XRD). The molecular functionalitiesof hydroxyl groups in polyphenols of A. aspera leaf extract were identified from FTIR absorption spectrum, and theyare responsible for the bioreduction of Cu+2 into Cu0 for the formation of CuNPs. The average size of the formedCuNPs from SEM studies was found to be 95 nm. The formed CuNPs were exhibited Face centered cubic (FCC)crystalline structure, and it was confirmed by XRD studies. TG-DTG analysis publicized the thermal stability ofNCFs. The tensile strength of NCFs was higher than normal cotton fabrics. These NCFs exhibited good antibacterialproperties which considered for making aprons and wound dressing materials in medicine and for packing materials

All Ceramic Materials in Dentistry: Past, Present and Future: A Review

Fixed partial dentures (FPDs) with high-strength all-ceramicsystems are necessary for replacing missing teeth. Widerange of materials and methods are available to fabricate arestoration outside the mouth and subsequently integratewith a tooth. The traditional methods of ceramic fabricationhave been described to be time-consuming, techniquesensitive, and rather unpredictable due to the many variablespresent which affect the outcome. All-ceramic restorations,has become a segment of dentistry which has experiencedtremendous improvements in the recent years. The increasinguse of polycrystalline alumina and zirconia as frameworkmaterials and the increasing popularity and variety ofcomputer-aided design and computer-aided manufacturing(CAD-CAM) systems seem to be mutually accelerating trendsover the last three decades. This article presents a review ofthe development of all-ceramic restorations, including theevolution and development of materials, technologies andhow to improve the strength of all-ceramic restorations, withrespect to survival, applications, strength, color, and aesthetics.The literature demonstrates that multiple all-ceramic materialsand systems that are currently available for clinical use andconcludes there is not a single universal material or, systemavailable to suit for all clinical situations.

Nanocomposite hydrogel-based biopolymer modified with silver nanoparticles as an antibacterial material for wound treatment

Authors report the synthesis of sodium alginate-polyvinyl alcohol-g-acrylamide (NaAlg-PVA-g-AAm) nanocompositehydrogels modified with silver nanoparticles (AgNPs) as an antibacterial agent. In this work, we used NaAlg isolateddirectly from brown algae and studied the effects of the NaAlg weight ratio and silver-ion concentration on the networkmatrix in the hydrogels via in situ polymerization. Successfully synthesized nanocomposites were characterized usingFourier transform infrared, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, andatomic absorption spectrometry. The best results were achieved with an average AgNPs size of approximately 20 nmallowing the AgNPs to be absorbed in the nanocomposite hydrogel matrix. Nanocomposite hydrogels displayed goodantibacterial activity against Escherichia coli and Staphylococcus aureus. The minimum inhibitory concentrations(MICs) of silver nitrate (AgNO3) for E. coli and S. aureus were 46.251 and 75.220 ppm, respectively. Conversely,the minimum bactericidal concentrations (MBCs) of AgNO3 for these bacteria were 185.004 and 300.880 ppm,respectively. The MBC/MIC ratio of the AgNO3 modified nanocomposite hydrogels was four for both bacteria. Theresults illustrated that the nanocomposite hydrogels had good antibacterial activity against Gram-positive and Gramnegative bacteria and can be suitable for applications in wound treatments.

Antimicrobial effects of edible nano-composite based on bean pod shell gum, nano-TiO2, and Mentha pulegium essential oil

Natural antioxidants in edible coatings can modify the structure and improves the functionality and applicabilityof the film in food industries. This study was done to determine the antimicrobial effect of nano-compositebased on bean pod shell gum (4% w/v), TiO2 nano-particles (NPs) (1%–2% w/v) and Mentha pulegiumessential oil (EO) (2%–4% v/v) on five food-borne pathogens in two categories, including Gram positives andthree Gram-negatives bacteria. The antimicrobial activity was tested using disk diffusion test. According to theresults, Gram-positive bacteria were more susceptible than Gram-negative bacteria. Increasing M. pulegiumEO and TiO2 NPs content increased the antimicrobial activity of the edible film based on bean pod shell gum,so that the treatment containing 4% v/v M. pulegium EO and 2% w/v TiO2 NPs led to the highest inhibitionzone (11.8–15.2 mm) compared to treatment containing 2% v/v M. pulegium EO and 1% w/v TiO2 NPs withinhibition zone range of 9.8–11.5 mm. In general, TiO2 NPs and M. pulegium EO improved the functionalproperties, including antimicrobial activity of the edible film based on bean pod shell gum which increases thepotential of films to be used for fresh products.

Síntesis y caracterización de nanocompuestos Fe3O4/Ag: su efecto contra Enterobacter aerogenes y Enterococcus faecaiis / Synthesisandcharacterization of nanocompounds Fe3O4/Ag: its effect against Enterobacter aerogenes and Enterococcus faecaiis / Síntese e caracterização de nanocompósitos Fe3O4/Ag: seu efeito contra Enterobacter aerogenes e Enterococcus faecaiis

Resumen En el presente trabajo, se reporta la síntesis y caracterización de nanopartículas magnéticas de magnetita/plata (Fe3O4/Ag) para el estudio de sus propiedades antibacterianas frente a las bacterias Enterobacter aerogenes (Gram-negativa) y Enterococcus faecaiis (Gram-positiva). Las nanopartículas magnéticas de magnetita (MNPs) se sintetizaron por el método de solgel, usando bromuro de cetiltrimetilamonio (CTAB) como surfactante. Posteriormente, en la dispersión coloidal de magnetita, se llevó a cabo la reducción química in situ de iones de plata, usando glucosa como agente reductor y polivinilpirrolidona (PVP) como agente dispersante, para obtener un nanocompuesto magnético Fe3O4/Ag. El análisis morfológico y espectroscópico de las nanopartículas de Fe3O4 y del nanocompuesto de Fe3O4/Ag fue realizado mediante la espectroscopia infrarroja con transformada de Fourier (FTIR), Raman, y Mössbauer (MS), además de la técnica de difracción de rayos X (DRX), la microscopía electrónica de barrido (SEM) y espectroscopia de energía dispersiva de rayos X (EDS). Las nanopartículas de Fe3O4 resultaron esféricas con un diámetro medio de 10 nm y el nanocompuesto de Fe3O4/Ag con un tamaño medio de 28 nm, el test antibacteriano indicó que el uso del nanocompuesto de Fe3O4/Ag a una concentración de 5 mg'mL-1 permite una inhibición total del crecimiento de los microorganismos estudiados a partir de una concentración inicial 108 bacterias mL-1.

Abstract In the present study, we report the synthesis and characterization of magnetite/silver magnetic nanoparticles (Fe3O4/Ag) and the study of their antibacterial properties against the bacteria Enterobacter aerogenes (Gramnegative) and Enterococcus faecaiis (Grampositive). Magnetite magnetic nanoparticles (MNPs) were prepared by a sol-gel method using cetyltrimethylammonium bromide (CTAB), as a surfactant, followed by in-situ chemical reduction of silver ions by glucose, and polyvinylpyrrolidone (PVP), as a dispersive agent, to obtain the antibacterial nanocomposite of Fe3O4/Ag. Morphological and spectroscopic studies of magnetite nanoparticles and nanocomposite were carried out using the Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Mössbauer spectroscopy (MS), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). Spherical Fe3O4 MNPs showed an average diameter of 10 nm and the average size for nanocomposite was 28 nm. The antibacterial test indicated that the use of the nanocomposite of Fe3O4/Ag at a concentration of 5 mg'mL-1 allowed a total inhibition of the growth of the microorganisms studied from an initial concentration of 108 bacteria mL-1.

Resumo No presente trabalho, relatamos a síntese e caracterização de nanopartículas magnéticas de magnetita/prata (Fe3O4/Ag) e o estudo de suas propriedades antibacterianas contra as bactérias Enterobacter aerogenes (Gram-negativo) e Enterococcus faecaiis (Gram-positiva). Nanopartículas magnéticas de magnetita (MNPs) foram sintetizadas pelo método solgel usando o bromuro de cetiltrimetilamonio (CTAB) como surfactante. Posteriormente, na dispersão coloidal de magnetita, a redução química in situ dos íons de prata foi realizada utilizando-se glicose, como agente redutor, e polivinilpirrolidona (PVP), como agente dispersante, para obter um nanocompósito magnético Fe3O4/Ag. A análise morfológica e espectroscópica das nanopartículas de Fe3O4 e do nanocompuesto de Fe3O4/Ag conduziu-se através da espectroscopia infravermelha com transformada de Fourier (FTIR), Raman, e Mössbauer (MS), además da técnica de raio X da deformação (DRX), a microscopia eletrônica de barrido (SEM) e a espectroscopia de energia dispersiva de raios X (EDS). As nanopartículas de Fe O têm formas esféricas com um diâmetro médio de 10 nm e o nanocompósito de Fe3O4/Ag com um tamanho promédio de 28 nm. O teste antibacteriano indicou que o uso do nanocompósito Fe3O4/Ag na concentração de 5 mg'mL-1 permitiu inibir totalmente o crescimento dos microrganismos estudados a partir de uma concentração inicial de 108 bactérias mL-1.

Formulation and in vitro characterization of anticancer drugs encapsulated chitosan/multi-walled carbon nanotube nanocomposites

We aimed to combine the nanoscale structure with bio-molecules to open the door for novel biology and nanotechnologyapplications. Multi-walled carbon nanotube (MWCNT) was combined with the biocompatible polymer chitosan (Cs)producing the Cs/MWCNT nanocomposite and utilized as a drug carrier for three types of drugs, namely 5-fluorouracil,curcumin, and water-soluble curcumin derivative. The produced nanocomposite was with a homogenous well-definedstructure that proved by transmission electronic microscopy, FT-IR, X-ray diffraction, and thermal gravimetricanalysis. The results of cytotoxicity assay measurement showed that the curcumin encapsulated Cs or Cs/MWCNTnanocomposite presented higher toxicity towards MCF-7 cancer cells compared with RPE1 normal cells indicatingto the selective effectiveness of curcumin nanocomposite towards the destruction of the carcinogenic MCF-7 cells. Invitro release studies showed that Cs/MWCNT nanocomposite possesses better slow controlled release performancethan chitosan indicating that there is a strong association between the drug and CNTs which triggers the release of thedrug for controlled drug release purposes

Effect of Silver (Ag) Nanoparticles on Structural and Mechanical Properties of (PMMA) Blend and its Application for Denture Base

The (PMMA-Ag) nano-composites films were prepared via photo polymerization method with different percentages (0.0%, 0.05%, 0.1%, 0.15% and 0.2%) of Ag. The structural, bacterial and mechanical properties of nano-composites were studied, FTIR spectra show a shift in peak position as well as a change in intensity. Scanning electron microscopy shows the surface morphology of the (PMM-Ag) nano-composites films. Three point bending testing, compressive strength, and impact strength were investigated and the results illustrate each mechanical property which improves the polymer characteristics. Then we reached that nano-composite materials are considered as the most important materials which are used as dental molds.

Highly sensitive simultaneous electrochemical determination of myricetin and rutin via solid phase extraction on a ternary Pt@r-GO@MWCNTs nanocomposite / 药物分析学报

The simultaneous electrochemical determination of myricetin and rutin remains a challenge due to their indistinguishable potentials. To solve this problem, we constructed a ternary platinum nanoparticle, reduced graphene oxide, multi-walled carbon nanotubes (Pt@r-GO@MWCNTs) nanocomposite via a facile one-pot synthetic method. Under the optimized conditions, the ternary Pt@r-GO@MWCNTs nanocomposite exhibited good electrocatalytic activity toward myricetin and rutin via solid phase extraction and excellent performance for the simultaneous determination of myricetin and rutin. The oxidation peak current of myricetin was proportional to its concentrations in the range of 0.05-50μM with a detection limit of 0.01μM (S/N = 3). The linear range for rutin was 0.05-50μM with a detection limit of 0.005μM (S/N = 3). The ternary nanocomposite sensor also exhibited good reproducibility and stability, and was successfully used for the simultaneous determination of myricetin and rutin in real orange juice samples with recoveries ranging between 100.57％and 108.46％.

Preparation of Site-specific Smart Nanocomposites for Drug Delivery and Study on Light-Controlled Cytarabine Release Performance / 中国药学杂志

OBJECTIVE: To prepare smart & site-specific drug carrier for controlled release purpose and study the bio-compatibilities and release performance.METHODS: By using high pressure thermo-heat method in autoclave, superparamagnetic core was obtained and further coated by SiO2 and MCM-41, therefore the “core-shell” structure was formed. To make the carrier “smart” and thus responsive to stimuli which was light in this research, the tunnels of the molecular sieve were grafted with gating molecules, 4,5-diazafluoren-9-one (indicated in the paper as DAFO). For bio-compatibilities testing, MTT in-vitro experiment was conducted. Cytarabine was used as test drug to preliminarily evaluate the controlled release performance of the drug carrier in vitro.RESULTS: The Fe3O4 nano-particles synthesized via high-pressure hydro-thermo procedure exhibited superparamagnetic with mean diameter of 280 nm. After SiO2 & molecular sieve coating steps and ligand grafting steps, the particles grew to 540 nm. The sub-structure of the carrier was confirmed by scanning/transmission electron microscope(SEM & TEM) and nitrogen adsorption/desorption. Our “smart” carrier was able to be guided to the sites or organs with magnetic field and more importantly it was able to unload drug molecules under 510 nm light irritation that could flip the gating-molecule. Furthermore, the drug carrier illustrated bio-compatibility and showed obvious cytotoxicity.CONCLUSION: The novel nanocomposites developed in this study can be used as targeted drug carrier.

Research Progress on Nitrite Electrochemical Sensor / 分析化学

Nitrite has been widely used in industrial and agricultural production,and is commonly found in food,drinking water,biology sample and environment.However,nitrite is a toxic inorganic pollutant that is very harmful to the health of human.A variety of strategies have been proposed for nitrite detection in recent years.Electrochemical approaches have gained more and more attention owing to simplicity,rapidity,sensitivity,low cost,etc.The research progresses of nanocomposite material sensor for electrochemical detection of nitrite based on carbon material,metal material,metal organic frameworks,and conducting polymer and enzyme in recent years are introduced from the perspective of composite electrode modification layer.The construction approaches and sensing performances of modified electrode are put special emphasis.At last,future trends of nitrite electrochemical sensor are also discussed.

Microleakage Evaluation in Teeth Restored with Experimental Dental Nanocomposite

@#Introduction: The aim of this study was to evaluate the experimental nanocomposite (Kelfil) against microleakage when bonded with two different types of bonding systems. Methods: Sixty sound extracted human permanent incisors were divided into six groups randomly. Each tooth was prepared with standardised Class III cavity on each proximal surface. The teeth were immersed in Rhodamin B dye for ten hours and sectioned to analyse the depth of dye penetration. The depth of the dye penetration was measured in micrometres by using confocal laser scanning microscope (CLSM). Results: The depth of the dye penetration in the groups was compared by ANOVA test. The results showed comparable microleakage between different types of composites. Conclusion: The experimental nanocomposite (Kelfil) in comparison to the commercially available nanocomposite and micro-hybrid composite has comparable microleakage when bonded using self-etching and total-etched adhesive systems.

Surface, thermal and hemocompatible properties of novel single stage electrospun nanocomposites comprising polyurethane blended with bio oilTM

ABSTRACT In this work, the physicochemical and blood compatibility properties of prepared PU/Bio oil nanocomposites were investigated. Scanning electron microscope (SEM) studies revealed the reduction of mean fiber diameter (709 ± 211 nm) compared to the pristine PU (969 nm ± 217 nm). Fourier transform infrared spectroscopy (FTIR) analysis exposed the characteristic peaks of pristine PU. Composite peak intensities were decreased insinuating the interaction of the bio oilTM with the PU. Contact angle analysis portrayed the hydrophobic nature of the fabricated patch compared to pristine PU. Thermal gravimetric analysis (TGA) depicted the better thermal stability of the novel nanocomposite patch and its different thermal behavior in contrast with the pristine PU. Atomic force microscopy (AFM) analysis revealed the increase in the surface roughness of the composite patch. Activated partial thromboplastin time (APTT) and prothrombin time (PT) signified the novel nanocomposite patch ability in reducing the thrombogenicity and promoting the anticoagulant nature. Finally the hemolytic percentage of the fabricated composite was in the acceptable range revealing its safety and compatibility with the red blood cells. To reinstate, the fabricated patch renders promising physicochemical and blood compatible nature making it a new putative candidate for wound healing application.