Versatile hydrogels: An efficient way to clean paper artworks

In this work we present innovative materials able to remove in a single, simple and not invasive treatment, different contaminants like starch paste from paper artworks. The materials, based on biocompatible hydrogels, overcome many of the problems usually faced by restorers during the cleaning of paper sample

New strategy for the cleaning of paper artworks: A smart combination of gels and biosensors

n this work an outlook on the design and application, in the cultural heritage field, of new tools for diagnostic and cleaning use, based on biocompatible hydrogels and electrochemical sensors, is reported. The use of hydrogels is intriguing because it does not require liquid treatment that could induce damage on artworks, while electrochemical biosensors not only are easy to prepare, but also can be selective for a specific compound and therefore are suitable for monitoring the cleaning process. In the field of restoration of paper artworks, more efforts have to be done in order to know how to perform the best way for an effective restoration. Rigid Gellan gel, made up of Gellan gum and calcium acetate, was proposed as a paper cleaning treatment, and selective biosensors for substances to be removed from this gel have been obtained by choosing the appropriate enzymes to be immobilized. Using this approach, it is possible to know when the cleanup process will be completed, avoiding lengthy and sometimes unnecessary cleaning material applications

Theoretical modeling of UV-Vis absorption and emission spectra in liquid state systems including vibrational and conformational effects: the vertical transition approximation

In this paper we describe in detail a general and efficient methodology, based on the perturbed matrix method and molecular dynamics simulations, to model UV-Vis absorption and emission spectra including vibrational and conformational effects. The basic approximation used is to consider all the chromophore atomic coordinates as semiclassical degrees of freedom, hence allowing the calculation of the complete spectral signal by using the electronic vertical transitions as obtained at each possible chromophore configuration, thus including the contributions of vibrations and conformational transitions into the spectrum. As shown for the model system utilized in this paper, solvated 1-phenyl-naphthalene, such an approximation can be rather accurate to reproduce the absorption and emission spectral line shape and properties when, as it often occurs, the vertical vibronic transition largely overlaps the other non-negligible vibronic transitions