Study of Ancient Paper and Detection of Microbiological Contamination Using Photoacoustic Technique

Ancient documents are of historical interest because they contain valuable information for future generations. One of the most common causes of documents damage and degradation is due to the presence of fungi. Therefore, it is very important to protect them from these microorganisms. In this work, TiO₂ nanoparticles (TiO₂NPs) were synthesized and used along with UV treatment for application as a potential antifungal against paper damage. Transmission electron microscopy (TEM) showed an average size of 70 nm for the nanoparticles. From scanning electron microscopy (SEM) micrographs, different structures of fungi in damaged cellulose fibers were observed. Energy dispersive X-ray spectrometry (EDS) detected the presence of elements related to organic and inorganic materials. Photoacoustic spectroscopy (PAS) as a non-invasive and versatile technique was used to study ancient documents deterioration presented in this manuscript. Through this technique, pigments produced by fungi in the wavelength between 277 nm and 700 nm were detected, being PAS an important characterization tool to study biodeterioration caused by fungi.