RESUMO

Antimicrobial films based on distinct polymer matrices, poly (vinyl alcohol) (PVA) or poly (N-isopropylacrylamide) (PNIPAAm), and silver nanoparticles (AgNPs) immobilized onto cellulose nanowhiskers (CWs) were successfully prepared by either casting or electrospinning. CWs were first functionalized with carboxylate groups (labeled as CWSAc) and later they were immersed in a silver nitrate solution (AgNO3). After Ag+ ions anchored in the COO- groups are chemically reduced to produce AgNPs. The CWSAc/AgNPs biological activity was evaluated against Staphylococcus aureus (S. aureus), Bacillus Subtilis (B. subtilis), Escherichia coli (E. coli), and Candida albicans (C. albicans). The materials were more effective against C. albicans that showed a MIC of 15.6 µg/mL. In the process of AgNPs synthesis, the activity of the stabilizing agent (gelatin) and concentration of precursor and reducing agents were evaluated. The synthesized polymeric films displayed good antimicrobial activity against S. aureus, E. coli, and Pseudomonas aeruginosa (P. aeruginosa) bacteria. The PVA films with CWSAc/AgNPs showed diameter of the inhibition halo of up to 11 mm. The results obtained displayed that the films obtained have a potential application to be used in different fields such as packaging, membrane filtration, wound dressing, clothing and in different biomedical applications.

Assuntos

Resinas Acrílicas/química , Antibacterianos/química , Celulose/química , Membranas Artificiais , Nanoestruturas/química , Álcool de Polivinil/química , Prata/química , Resinas Acrílicas/farmacologia , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Infecções Bacterianas/prevenção & controle , Candida albicans/efeitos dos fármacos , Candidíase/prevenção & controle , Celulose/farmacologia , Humanos , Nanopartículas Metálicas/química , Álcool de Polivinil/farmacologia , Prata/farmacologia

RESUMO

Cellulose nanowhiskers (CWs) extracted from cotton fibers were successfully modified with distinct anhydrides structures and used as additives in poly(vinyl alcohol) (PVA) nanocomposite films. The surface modification of CWs was performed with maleic, succinic, acetic or phthalic anhydride to compare the interaction and action the carboxylic groups into PVA films and how these groups influence in mechanical properties of the nanocomposites. CWs presented a high degree of crystallinity and good dispersion in water, with average length at the nanoscale. The addition of specific amounts (3, 6 and 9 wt.%) of modified-CWs increased up to 4.4 times the storage modulus (PVA88-CWSA 9 wt.%), as observed from dynamic mechanical analysis (DMA), compared to the bare PVA films. A significant increase in mechanical properties such as tensile strength, elastic modulus, and elongation at break showed a close relationship to the amount and chemical surface characteristics of CWs added, suggesting that these modified-CWs could be explored as reinforcement additives in PVA films.