NANOSTRUCTURED AGAR MATS FOR APPLICATION IN THE CLEANING AND DISINFECTION OF SENSITIVE SURFACES

Cleaning and disinfection are critical procedures in the restoration of Cultural Heritage, as they are often irreversible and have a significant impact on the long-term conservation of artworks. Traditional cleaning methods can be invasive and difficult to control, leading to the need for innovative, non-destructive alternatives. This study explores the use of Agar, a natural polysaccharide extracted from red algae of the Gracilariales and Gelidiales orders, as a key component in the development of nanostructured cleaning and disinfection materials. Agar has been widely employed in Cultural Heritage conservation due to its gelling properties, biocompatibility, and ability to form stable hydrogels that enable controlled cleaning but leaving residues. However, its potential in nanofiber-based cleaning applications remains unexplored. Here, we report the fabrication of ready-to-use electrospun mats composed of Agar nanofibers, produced through electrospinning—a cost-effective and versatile technique that utilizes a high electric field to generate ultrafine fibers. The resulting nanostructured mats exhibit high porosity, a large surface-to-volume ratio, and the ability to retain and release solvents in a controlled manner. Moreover, the electrospinning process enables the incorporation of functional fillers, nanostructures, and bioactive agents, further enhancing the cleaning and antimicrobial properties of the mats. Agar/poly(ethylene oxide) (PEO) solutions were prepared at three different concentrations (30:70, 50:50, and 70:30 ratios) and characterized through rheological and spectroscopic analyses to evaluate viscosity and polymer interactions. The electrospun mats were then analysed using Field-Emission Scanning Electron Microscopy (FE-SEM) and mechanical testing. To enhance their antimicrobial functionality, agar-based mats were further modified with gold and silver nanoparticles, synthesized in situ through a green bottom-up approach that eliminates the need for chemical reducing agents. The incorporation of these noble metal nanoparticles imparts antibacterial and antifungal properties, making the nanocomposite mats suitable for disinfection and biofilm prevention in Cultural Heritage. This research demonstrates, for the first time, the successful fabrication of Agar nanofibers (with average diameters ranging from 85 to 260 nm, depending on the Agar/PEO ratio) for cleaning and disinfection applications.