RESUMO
The purpose of this study was to synthesize a new magnetic material with antimicrobial properties, incorporated into a biopolymer and containing silver nanoparticles (Ag NP) prepared extract of Eugenia umbelliflora as a reducing agent. Silver nanoparticles incorporated into magnetic nanocomposite O-carboxymethylchitosan/y-Fe2O3/Ag0 (CMAgE) composite were synthesized using an extract of E. umbelliflora. The antimicrobial activity of the pathogenic microorganism is reported here. The synthesized nanoparticles were also characterized, and quantified by Ag analysis. The minimum inhibitory concentrations (MIC) of CMAgE against Staphylococcus aureus, Escherichia coli, and Candida albicans were 16.5, 1000 and 500 µg/mL, respectively. The results show that these materials have significant synergistic effect on each other. The potential phytotoxic effect of the nanocomposites was evaluated using Cucumis sativus seeds. The positive values for seedling elongation inhibition (SEI) show that CMAgE and methanol extract of Eugenia umbelliflora (Eug) cause growth inhibition at a concentration of 1000 mg/L. The germination index (GI) values of 40% and 80% at 1000 mg/L, for CMAgE and Eug, respectively, showed inhibition of germination. CMAgE and Eug showed cytotoxic effects against Artemia salina nauplii, with LC50 values of 72.5 µL/mL and < 5.0 µL/mL respectively, after 48 h.
Assuntos
Antibacterianos/farmacologia , Artemia/crescimento & desenvolvimento , Quitosana/análogos & derivados , Eugenia/química , Compostos Ferrosos/química , Nanopartículas Metálicas/administração & dosagem , Extratos Vegetais/farmacologia , Prata/química , Animais , Antibacterianos/química , Artemia/efeitos dos fármacos , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Quitosana/química , Nanopartículas Metálicas/química , Nanocompostos/administração & dosagem , Nanocompostos/químicaRESUMO
In this paper, nano-hybrid particles of Ag@Fe2O3 based on O-carboxymethylchitosan were successfully synthesized using different reducing agents (NaBH4, sucrose) and without reducing agent. The smallest silver nanoparticles were those prepared without reducing agent (â¼5±3nm). The average size of silver particles prepared with NaBH4 is around 5-15nm, and for samples prepared with sucrose, the average particle size is 10-25nm. The magnetization curves are roughly reversible, indicating that γ-Fe2O3 nanoparticles transit to a superparamagnetic state. Nanocomposites subjected to antimicrobial tests showed great antimicrobial activity against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria, and good activity against the yeast Candida albicans and resistant strains of Staphylococcus aureus. The antibacterial behavior as a function of time was investigated in microbial growth kinetics, and the best nanocomposite was the one without reducing agent, which completely inhibited microbial growth for 48h.
Assuntos
Anti-Infecciosos/síntese química , Quitosana/análogos & derivados , Nanopartículas Metálicas/química , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Candida albicans/efeitos dos fármacos , Candida albicans/crescimento & desenvolvimento , Quitosana/síntese química , Quitosana/química , Quitosana/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Compostos Férricos/síntese química , Compostos Férricos/química , Compostos Férricos/farmacologia , Testes de Sensibilidade Microbiana , Nanocompostos/química , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimentoRESUMO
This paper studied the synthesis, characterization and use of the magnetic chitosan nanogel for carrying meleimidic compounds. The hydrogel polymer was prepared using O-carboxymethylchitosan, which was crosslinked with epichlorohydrin for subsequent incorporation of iron oxide magnetic nanoparticles. The characterization revealed that the magnetic material comprises about 10% of the hydrogel. This material is comprised of magnetite and maghemite and exhibits ferro-ferrimagnetic behavior. The average particle size is 4.2 nm. There was high incorporation efficiency of maleimides in the magnetic nanogel. The release was of sustained character and there was a greater release when an external magnetic field was applied. The mathematical model that best explained the process of drug release by the magnetic hydrogel was that of Peppas-Sahlin. The magnetic nanogel proved to be an excellent candidate for use in drug-delivery systems.
Assuntos
Antineoplásicos/química , Quitosana/análogos & derivados , Portadores de Fármacos/química , Polietilenoglicóis/química , Polietilenoimina/química , Adsorção , Animais , Antineoplásicos/metabolismo , Varredura Diferencial de Calorimetria , Bovinos , Quitosana/síntese química , Quitosana/química , Portadores de Fármacos/síntese química , Liberação Controlada de Fármacos , Epicloroidrina/química , Magnetismo , Nanopartículas de Magnetita/química , Nanogéis , Tamanho da Partícula , Soroalbumina Bovina/química , Espectroscopia de Mossbauer , TermogravimetriaRESUMO
PURPOSE: The discharge of colored effluents from industries is an important environmental issue and it is indispensable to remove the dyes before the water gets back to the rivers. The magnetic adsorbents present the advantage of being easily separated from the aqueous system after adsorption by positioning an external magnetic field. METHODS: Magnetic N-lauryl chitosan (L-Cht/γ-Fe(2)O(3)) particles were prepared and characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, and vibrating sample magnetometry. Remazol Red 198 (RR198) was used as a reactive dye model for adsorption on L-Cht/γ-Fe(2)O(3). The adsorption isotherms were performed at 25°C, 35°C, 45°C, and 55°C and the process was optimized using a 2(3) factorial design (analyzed factors: pH, ionic strength, and temperature). The desorption and regeneration studies were performed in a three times cycle. RESULTS: The characterization of the material indicated that the magnetic particles were introduced into the polymeric matrix. The pseudo-second order was the best model for explaining the kinetics and the Langmuir-Freundlich was the best-fitted isotherm model. At room temperature, the maximum adsorption capacity was 267 mg g(-1). The material can be reused, but with a decrease in the amount of adsorbed dye. CONCLUSIONS: L-Cht/γ-Fe(2)O(3) is a promising material to remove RR198 and probably other similar reactive dyes from aqueous effluents.
Assuntos
Compostos Azo/química , Corantes/química , Naftalenossulfonatos/química , Poluentes Químicos da Água/química , Adsorção , Quitosana/química , Cinética , Fenômenos Magnéticos , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Indústria Têxtil , TermogravimetriaRESUMO
Magnetic N-benzyl-O-carboxymethylchitosan nanoparticles were synthesized through incorporation and in situ methods and characterized by Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, and magnetization measurements. Indomethacin was incorporated into the nanoparticles via the solvent evaporation method. The indomethacin-loaded magnetic nanoparticles were characterized by the same techniques, and also by transmission electron microscopy. The nanoparticles containing the polymer showed a drug loading efficiency of between 60.8% and 74.8%, and the magnetic properties were not significantly affected by incorporation of the drug. The in vitro drug release study was carried out in simulated body fluid, pH 7.4 at 37°C. The profiles showed an initial fast release, which became slower as time progressed. The percentage of drug released after 5 h was between 60% and 90%, and the best fitting mathematical model for drug release was the Korsmeyer-Peppas model, indicating a Fickian diffusion mechanism.