Synthesis of novel silver nanocomposite hydrogels based on polyurethane/poly(ethylene glycol) via aqueous extract of oak fruit and their antibacterial and mechanical properties

In this study, novel hydrogels based on polyurethane/polyethylene glycol (PU/PEG) and their silver nanocomposites (PU/PEG/Ag x, x = 100, 200, 400, and 800) were developed using click chemistry and a green method. Mechanical analysis showed that introducing of silver nanoparticles (AgNPs) into hydrogels and increasing the content increased their mechanical properties dramatically. Tensile strength and elongation at break increased from 0.2 MPa and 105% for PU/PEG to 2.5 MPa and 210% for PU/PEG/Ag 800. Similarly, the compressive strength increased from 5 to 55 MPa. Investigation of the SEM images showed that the AgNPs were homogeneously dispersed throughout the hydrogel network, and through the incorporation of silver nanoparticles in hydrogels, the pore size of hydrogels decreased. Therefore, the swelling degree of hydrogels decreased by increasing the content of AgNPs. FTIR spectroscopy and X-ray photoelectron spectroscopy (XPS) demonstrated that the interaction of network heteroatoms with AgNPs was responsible for stabilizing silver nanoparticles. The antibacterial properties of nanocomposites were evaluated against Pseudomonas aeruginosa and Staphylococcus aureus bacteria. These nanocomposites showed significant activities against S. aureus bacteria. In addition, the cell viability test showed that these nanocomposites had good biocompatibility (84% cells viable). Therefore, they could be favorable candidates for wound dressing applications.