Eco-friendly development of sterile chitosan-based aerogels for wound dressing applications using integrated scCO2 processing.

Abstract

The development of novel and eco-friendly wound dressings using biopolymers faces challenges related to their processing/sterilisation. Supercritical CO₂ (scCO₂) drying represents an efficient and sustainable solution, by enabling the production of sterilised materials with high surface area/porosity while preserving essential properties. This study introduces a novel integrated process for developing sterile chitosan (CS) aerogels crosslinked with tripolyphosphate (TPP) and polyvinyl alcohol (PVA). The process combines high-pressure solvent exchange, scCO₂ drying and sterilisation, with one additional step for active pharmaceutical ingredients (API) impregnation. Results show that the properties of the CS-based aerogels, such as surface area, porosity, swelling capacity, mechanical resistance to compression, and cytotoxicity can be tuned depending on TPP crosslinking degree. Adding PVA improves structural homogeneity and flexibility but reduces surface area and increases toxicity. The CS-TPP_2.5% aerogel emerged as the most promising, offering good mechanical properties (4.93 ± 0.75 N), high surface area (190.80 ± 9.80 m².g^-1), porosity (71.12 ± 1.41 %), and low cytotoxicity, making it suitable for wound dressings. The integrated process was successfully applied to a selected CS-based aerogel, producing a sterile aerogel loaded with naringin (model API) in a short timeframe. Overall, this work offers a green approach to produce sterile API loaded aerogels, suitable for biomedical applications.