Efficacy of co-loading Ag nanoparticles and metronidazole in PEG–gelatin-based sponges for the treatment of chronic wounds

Polymer-based sponges loaded with antibacterial agents are potential wound dressings ideal for treating bacteria-infected wounds. Gelatin/poly (ethylene glycol) (PEG) sponge-based wound dressings loaded with metronidazole and Ag nanoparticles with different degrees of cross-linking were prepared, and their capability to treat infected wounds in vitro was evaluated. The degree of cross-linking of the sponges varied, and the porosity of the sponges was in the range of 15.64–91.10%. The amount of gelatin used to prepare the sponges influenced the porosity of the sponges. The sponges displayed an initial burst drug release of metronidazole followed by a sustained release profile. The sponges exhibited considerable antibacterial activity against Gram-positive and Gram-negative bacteria. The % cell viability of the sponges was in the range of 71.17–86.10%, indicating distinguished biocompatibility. The in vitro experiment showed that the sponge loaded with metronidazole, SAM2%, displayed a significant reduction of 66.68% in the scratch area compared to the sponge loaded with a combination of silver nanoparticles and metronidazole with a closure rate of 46.61% at 96 h. The promising features of the sponges indicate that they are potential wound dressings for treating infected wounds.