Tannin-stabilized silver nanoparticles and citric acid added associated to cellulose nanofibrils: effect on film antimicrobial properties

Abstract

The aim of this work was to evaluate the potential of cellulose nanofibrils (CNFs) films treated with commercial solution of Ag nanoparticles stabilized with natural tannin and silane groups in the bacteria growth inhibition. The films were produced with commercial pulps of pine and eucalyptus treated with sodium hydroxide (5% w/v) and calcium hydroxide (10% w/v), respectively. The bacteria selected for the inhibition test were the gram-positive Listeria monocytogenes and gram-negative Salmonella enteriditis. The films performance was investigated by the antimicrobial activity using disc diffusion. In addition, the pulps were evaluated by their chemical composition, water retention index (WRI) and X-ray diffraction (XRD). The content of hemicelluloses in the treated pine pulp (11.32%) was lower in comparison to the found in the treated eucalyptus pulp (14.46%). The XRD diffractogram presented higher crystallinity index for the treated eucalyptus pulp (70%) with a characteristic peak of calcium carbonate. The treated eucalyptus pulp showed higher WRI and viscosity values in relation to the treated pine pulp. Growth inhibitory halos were more expressive when the treatment with both antimicrobial solutions were proceeded in the films produced with pine CNFs with addition of the citric acid. The effect of the nanoparticles stabilized with tannin must be highlighted, mainly on the bacterium S. enteriditis.

The Influence of Microcrystalline and Nanofibrillated Cellulose in XSBR Polymers on the Mechanical Properties of Jute Textile-Reinforced Cementitious Composites

“…The patterns were deconvoluted using the Gaussian function with Magic Plot 2.9 (Magicplot Systems). For the amorphous halo, the cellulose II with a FWHM = 9 was used, only varying its intensity [35]. The crystalline fractions of studied pulps were calculated using peak deconvolution and an area-based method (Equation 1), because the amorphous component used in the Segal method is substantially influenced by the overlap of crystalline peaks [16].…”

Ag-Based Synergistic Antimicrobial Composites. A Critical Review

“…It has been proposed that solubility might be a more important determinant of antibacterial activity than the surface charge, as such is case of citrate-coated AgNPs, as well [ 222 ]. It was possible to increase inhibition performance of cellulose nanofibrils (CNFs) films treated with commercial solution of AgNPs against Gm+ L. monocytogenes and Gm− S. enteriditis ; the antimicrobial effect was potentiated by the addition of 5% citric acid in the CNFs [ 223 ].…”