Shelf-life of sterilised alginate-gelatine aerogels developed through an integrated high-pressure and supercritical CO2 process

Shelf-life studies on sterile biopolymeric aerogels are scarce. This study investigated four storage conditions (C₁ - C₄), varying temperature, humidity, and light exposure, on alginate-gelatine aerogels produced via an integrated high-pressure and supercritical CO₂ process. Mild storage conditions (C₁ - 25 ºC, 60 % humidity and no light) effectively preserved aerogels’ structural and functional properties, with minimal changes over time. In contrast, accelerated storage conditions (C₂ - 40 ºC, 75 % humidity, no light) induced hydrolytic degradation, causing chain scission and structural damage, due to heat and moisture. Light exposure at mild storage conditions (C₃) induced mild photooxidative effects without significant impact on properties. The combination of all stressors at accelerated storage (C₄) severely compromised network, thermal and mechanical stability. Swelling profile increased under storage but it was mitigated under conditions with high temperature and humidity. Storage for 6 months did not promote microbial growth on the sterilised aerogels under the tested conditions, confirming the effectiveness of the CO₂ sterilisation process. Aerogels did not present cytotoxicity, regardless of the storage conditions, however wound-healing potential declined under storage conditions C₂, C₃ and C₄, while C₁ maintained performance for three months.