RESUMO
An antimicrobial polyacrylic silver salt (freshly prepared, stored for one year and model-aged) was studied by physical-chemical techniques for nanoparticle detection. In all cases, this salt represents a composite of radical-enriched macromolecules and silver(0) nanoparticles. As time passed, the initial small spherical nanoparticles were converted into larger non-spherical silver nanoparticles. The initial highly water-soluble antimicrobial solid nanocomposite almost loses its solubility in water and cannot be used as an antimicrobial agent. Unlike insoluble solid silver polyacrylate, its freshly prepared aqueous solution retains a liquid-phase consistency after one year as well as pronounced antimicrobial properties. The mechanism of these spontaneous and model-simulated processes was proposed. These results have attracted attention for officinal biomedicinal silver salts as complex radical-enriched nanocomposite substances; they also indicate contrasting effects of silver polymeric salt storing in solid and solution forms that dramatically influence antimicrobial activity.
Assuntos
Anti-Infecciosos , Nanopartículas Metálicas , Nanocompostos , Antibacterianos/química , Antibacterianos/farmacologia , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Nanopartículas Metálicas/química , Nanocompostos/química , Polímeros , Sais/farmacologia , Prata/química , Água/químicaRESUMO
New nontoxic hydrophilic nanocomposites containing metallic silver nanoparticles (AgNPs) in a polymer matrix were synthesized by the chemical reduction of silver ions in an aqueous medium. A new nontoxic water soluble copolymer of 1-vinyl-1,2,4-triazole and N-vinylpyrrolidone synthesized by free radical-initiated polymerization was used as a stabilizing agent. Transmission electron microscopy, scanning electron microscopy, ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, atomic absorption, and thermogravimetric analysis were used to characterize polymeric AgNPs nanocomposites. The results showed that the diameter of the synthesized AgNPs ranged from 2 to 6 nm. The toxicity of the initial copolymer of 1-vinyl-1,2,4-triazole and N-vinylpyrrolidone and its nanocomposite with AgNPs was found to be more than 5,000 mg/kg. The synthesized AgNP polymeric nanocomposite showed significant antimicrobial activity against different strains of Gram-negative and -positive bacteria. The minimum inhibitory concentrations suppressing the growth of the microorganisms ranged from 0.5 to 8 µg/mL and the minimum bactericidal concentrations ranged from 0.5 to 16 µg/mL. The fabricated AgNP nanocomposites are promising materials for the design of novel nontoxic hydrophilic antiseptics and antimicrobial components for medical purposes.
Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Nanopartículas Metálicas/administração & dosagem , Nanocompostos/química , Pirrolidinonas/química , Prata/administração & dosagem , Triazóis/química , Animais , Antibacterianos/química , Feminino , Masculino , Nanopartículas Metálicas/química , Camundongos , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Polímeros/administração & dosagem , Polímeros/química , Prata/química , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios XRESUMO
New water-soluble nontoxic nanocomposites of nanosized silver particles in a polymer matrix were synthesized by a green chemistry method. Nontoxic poly(1-vinyl-1,2,4-triazole) was used as a stabilizing precursor agent in aqueous medium. Glucose and dimethyl sulfoxide were used as the silver ion-reducing agents to yield silver nanoparticles 2-26 nm and 2-8 nm in size, respectively. The nanocomposites were characterized by transmission electron microscopy, ultraviolet-visible and Fourier transform infrared spectroscopy, X-ray diffraction, atomic absorption, and thermogravimetric data analysis. The nanocomposites showed strong antimicrobial activity against Gram-negative and Gram-positive bacteria.