RESUMO
Nanocomposites of functionalized carbon nanotubes (CNTsf) as nanofillers, and a copolymer of star-shaped poly(ε-caprolactone) (stPCL) and poly(ethylene glycol) (PEG) as a polymeric matrix were synthesized, characterized, and their resistance to the growth of Staphylococcus aureus and Pseudomonas aeruginosa was evaluated. CNTsf contain hydroxyl, carboxyl and acyl chloride groups attached to their surface. Nanocomposites were prepared by mixing CNTsf to a solution of stPCL-PEG copolymer. Raman and FT-IR spectroscopies confirm the functionalization of carbon nanotubes (CNTs). Star-shaped PCL-PEG copolymer was characterized by Gel permeation chromatography (GPC), and 1H-NMR and 13C-NMR spectroscopies. X-ray photoelectron spectroscopy (XPS) shows that CNTsf are grafted to the stPCL-PEG copolymer. Crystallization behavior of the nanocomposites depends on the amount of CNTsf used in their preparation, detecting nucleation (nanocomposites prepared with 0.5 wt.% of CNTsf) or anti-nucleation (nanocomposites prepared with 1.0 wt.% of CNTsf) effects. Young's Moduli and thermal stability of nanocomposites were higher, but their resistence to the proliferation of Staphylococcus aureus and Pseudomonas aeruginosa was lower than the observed for their pure polymer matrix.
Assuntos
Antibacterianos/química , Etilenoglicóis/química , Nanocompostos/química , Nanotubos de Carbono/química , Poliésteres/química , Proliferação de Células/efeitos dos fármacos , Fenômenos Mecânicos , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Propriedades de SuperfícieRESUMO
This work reports the synthesis and characterization of a new material obtained by mixing the hybrid natural-synthetic chitosan-g-glycidyl methacrylate (CTS-g-GMA) biopolymer and xanthan gum (X). All materials were characterized by infrared spectroscopy (FTIR), X-ray diffraction, and thermal analysis (DSC and TGA) and the results were contrasted with those of the precursor materials. The swelling index of the hydrogels decreases when the GMA mass percentage increases. The X-ray diffraction patterns show that the hybrid hydrogels are amorphous in contrast to chitosan (CTS), which is semi-crystalline. FTIR analysis confirms the existence of physical interactions among constituents. Rheological properties, η, G', and G", were determined as a function of flow allowing one to conclude that (CTS-g-GMA)-X behaves as physical hydrogel. Additionally, we report viability of fibroblasts when cultured onto the synthesized hydrogels. This study shows that these hydrogels support cell viability and have potential for use in biomedical engineering applications.
Assuntos
Quitosana/química , Compostos de Epóxi/química , Metacrilatos/química , Ácidos Polimetacrílicos/síntese química , Polissacarídeos Bacterianos/química , Polissacarídeos Bacterianos/síntese química , Varredura Diferencial de Calorimetria , Quitosana/síntese química , Compostos de Epóxi/síntese química , Fibroblastos/efeitos dos fármacos , Humanos , Hidrogéis , Metacrilatos/síntese química , Ácidos Polimetacrílicos/química , Ácidos Polimetacrílicos/farmacologia , Polissacarídeos Bacterianos/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios XRESUMO
Poly(methyl methacrylate) nanosize particles, made by microemulsion polymerization, were dispersed in an acrylamide aqueous solution, which was polymerized in the presence of a cross-linking agent to yield microstructured hydrogels. The kinetics of swelling and the mechanical properties of these hydrogels were investigated as a function of concentration of particles. The microstructured hydrogels exhibit higher equilibrium swelling and larger Young modulus than conventional (that is, without particles) polyacrylamide hydrogel. The morphology of the microstructured hydrogels was examined by transmission electron microscopy.
