Gellan gum/titanium dioxide nanoparticle hybrid hydrogels for the cleaning and disinfection of parchment

Parchment is the support of several documents kept in libraries and archives all around the world. Much of this cultural heritage is rapidly degrading due to different causes, in particular fungi, with the risk of being lost. In recent decades new methods have been tried to improve the conservation, protection and usability of library and archive materials. In this work we showed a cleaning method of old documents in parchment bio-deteriorated by fungi. This method is easy, not expensive, and respectful of the document characteristics. In particular, it was evaluated the effectiveness of gellan gum and titanium dioxide nanoparticles hydrogels in cleaning and disinfecting parchment samples contaminated by Penicillium chrysogenum and Cladosporium cladosporioides, which are two fungi notorious for their attacks to parchment cultural heritage. Results showed that the mechanical soft action of gellan gum hydrogels combined with the photo-catalytic activity of titanium dioxide nanoparticles allow an important cleaning and disinfection of parchment with a consequent preservation from further fungal colonization of samples over long time when compared to untreated ones.