• calcium peroxide
• hypoxia
• wound dressing
• oxygen-releasing hydrogel
• wound healing

Chronic skin wounds typically exhibit hypoxia (oxygen levels smaller than 10 mmHg). This factor delays healing, since at least 40 mmHg of oxygen are required to sustain reparative cell processes. Oxygen-releasing hydrogel dressings constitute an attractive alternative to hyperbaric rooms, which have systemic side effects. This thesis aims to develop an oxygen-releasing alginate-based dressing for chronic wounds incorporating catalase, an enzyme that accelerates the conversion of calcium peroxide into oxygen upon hydrolyzation. Hydrogels with different alginate concentrations (0.5, 1, and 2% w/v in water) were firstly crosslinked in-situ and then exposed for three different timings (1, 5, and 10 min) to an external crosslinking agent. The hydrogels’ pore diameters, mechanical properties and stability over time in an aqueous environment were characterized to identify the optimal trade-off enabling oxygen diffusion and showing skin-mimicking mechanical properties. The optimal hydrogel formulation (2% w/v, crosslinked for 1 min) was used to study the oxygen release profile. Calcium peroxide was added to the upper surface of the hydrogel (2% w/v relative to the hydrogel volume), and an oxygen sensor measured the oxygen tension. The hydrogel allowed to reach 40 mmHg of oxygen after 6 hours. While several parameters (e.g., the calcium peroxide quantity) still need to be optimized, this work lays the groundwork for building a sustained oxygen release system.