How to tune a paper cleaning process by means of modified gellan hydrogels

Paper manuscripts are among the most valuable historical artifacts, but they are also very fragile. Furthermore, they were often strengthened by gluing external materials (like wooden or cardboard lining paper) to the original piece. The glues induced structural transformations that accelerate the degradation processes of the artwork itself. In this work, we present efficient and versatile multicomponent materials able to remove specific contaminants from paper artworks in a single, simple and not invasive approach. The materials are based on a rigid gellan hydrogel as a carrier for tuned cleaning agents, such as proteinase K enzyme, which is able to hydrolyze not easily removable glues into smaller fragments soluble into the gel, and suitable polimeric surfactants capable to remove hydrophobic contaminants. To assess the effectiveness and safety of the proposed cleaning method, we have employed a multitechnique approach, using several spectroscopic techniques, rheology characterization, scanning electron microscopy, high-performance liquid chromatography analysis, and pH measurements.