Composite Hydrogels with Embedded Silver Nanoparticles and Ibuprofen as Wound Dressing

The wound healing process is often slowed down as a result of complications from bacterial infections and inflammatory reactions. Therefore, it is necessary to develop dressings with fast antibacterial and anti-inflammatory activity that shorten the wound healing period by promoting cell migration and proliferation. Chitosan (CS)-based hydrogels have been widely studied for their antibacterial and wound healing capabilities. Herein, we developed a composite hydrogel based on CS and PVA embedding silver nanoparticles (AgNPs) with antibacterial properties and ibuprofen (Ib) as an anti-inflammatory agent. The hydrogel prepared by double physical cross-linking, with oxalic acid and by freeze-thawing, loaded with 0.225 wt.% AgNPs and 0.264 wt.% Ib, displayed good mechanical properties (compressive modulus = 132 kPa), a high swelling degree and sustained drug delivery (in simulated skin conditions). Moreover, the hydrogel showed strong antibacterial activity against S. aureus and K. pneumoniae due to the embedded AgNPs. In vivo, this hydrogel accelerated the wound regeneration process through the enhanced expression of TNF alpha IP8, by activating downstream cascades and supporting the healing process of inflammation; Cox2, which enhances the migration and proliferation of cells involved in re-epithelization and angiogenesis; MHCII, which promotes immune cooperation between local cells, eliminating dead tissue and controlling infection; the intense expression of Col I as a major marker in the tissue granulation process; and aSMA, which marks the presence of myofibroblasts involved in wound closure and indicates ongoing re-epithelization. The results reveal the potential healing effect of CS/PVA/AgNPs/Ib hydrogels and suggest their potential use as wound dressings.