Silver ion loaded 3-aminopropyl trimethoxysilane -modified Fe3O4 nanoparticles for the fabrication of carrageenan-based active packaging films.

Fe3O4 nanoparticle loaded with silver ion was prepared as a more efficient, safer, and less environmentally hazardous silver-based antibacterial nanomaterial. The Fe3O4 nanoparticle was modified using 3-aminopropyl trimethoxysilane (APTMS) to enhance the silver ion adsorption capacity and antibacterial activity. Silver ions were adsorbed on pristine Fe3O4 and Fe3O4@NH2 to enhance antibacterial activity. Energy dispersive spectroscopy (EDS) results showed that Fe3O4 adsorbed 2.74 wt% of Ag, whereas Fe3O4@NH2 adsorbed 9.88 wt%. Pristine Fe3O4NP, silver ion loaded Fe3O4 (Fe3O4-Ag), and silver ion loaded Fe3O4@NH2 (Fe3O4@NH2-Ag) were used to manufacture carrageenan-based composite films. Compared with Fe3O4-Ag, Fe3O4@NH2-Ag exhibited stronger antimicrobial activity against E. coli (8.82 vs. 5.02 log reduction) and L. monocytogenes (10.09 vs. 3.93 log reduction). While the addition of Fe3O4 significantly reduced the WCA of the carrageenan films from 61.1 ± 5.4 ° to 37.2 ± 2.1 °, the additions of Fe3O4-Ag and Fe3O4@NH2-Ag reduced the WCA of the film to a lesser extent (56.9 ± 4.6 ° and 56.9 ± 4.6 °, respectively). Fe3O4NP also improved the thermal stability of carrageenan over Fe3O4@NH2-Ag (22 °C vs. 13 °C) and UV blocking properties (T280, 0.1 ± 0.0 % vs. 3.3 ± 1.5 %).

A novel amino cellulose derivative using ATRP method: Preparation, characterization, and investigation of its antibacterial activity.

In this study, we prepared a novel amino cellulose derivative (benzyl cellulose-g-poly [2-(N,N-Dimethylamino)ethyl methacrylate]) via a homogeneous ATRP method. The successful synthesis of the novel amino cellulose was confirmed by FT-IR and 1H NMR. This study addressed the different characteristics of the prepared polymer including the thermal stability, solubility, and X-ray diffraction pattern. The antibacterial activity of the synthesized cellulose derivative was investigated using the diffusion disk method against both gram-negative (Escherichia coli, Salmonella enterica) and gram-positive (Staphylococcus aureus, Bacillus subtilis) bacteria. Based on the inhibition zone, it was confirmed that the prepared benzyl cellulose-g-PDMAEMA possesses acceptable antibacterial activity against Escherichia coli, Salmonella enterica, and Staphylococcus aureus while Bacillus subtilis is resistant to the prepared polymer. Also according to the inhibition zone, it was shown that benzyl cellulose-g-PDMAEMA has more impact on E. coli and Salmonella enterica than Staphylococcus aureus. Molecular dynamics simulation was also used to study the interaction of the synthesized cellulose derivative with a model membrane which presented atomistic details of the polymer-lipid interactions. According to the results obtained from the molecular dynamics simulation, the polymer was able to destabilize the structure of the membrane and clearly express its signs of degradation.