Enzyme-loaded bacterial nanocellulose aerogel as a biocleaning material for artwork restoration

The absorbent materials used for biocleaning in art conservation requires continuous development, particularly in enhancing their capability to deliver enzymes and aqueous solutions for cleaning artwork surfaces. In this study, bacterial nanocellulose (BNC) was developed as a carrier for enzyme delivery systems. Various dehydration techniques were applied to transform the BNC hydrogel into xerogel, cryogel, and aerogel to evaluate their performances in liquid reloading and the properties of the rehydrated structures. The results showed that the aerogel demonstrated excellent shape recovery within 2 h and achieved approximately 80% water uptake within 4 h. The hydrogel from liquid-loaded aerogel maintained its elasticity and plastic deformation damping properties. This hydrogel exhibited a slow-release property without creating stains beyond the working area for placement times on aged-sized canvas shorter than 120 min. This is useful knowledge to control the delivery of cleaning solutions for unstable collection surfaces. Moreover, it showed high performance in enzyme immobilization by primarily releasing the α-amylase matrix rather than its solvent, as evidenced by a higher maltose concentration compared to the cotton pad (used as a control sample). This finding suggests the feasibility of using BNC aerogel as an absorbent material for enzyme loading and delivery in biocleaning applications.