Electrospun Agar-Based Nanocomposite Mats for Artworks Disinfection

Disinfection is a critical and irreversible process in the restoration of Cultural Heritage, significantly impacting the long-term preservation of artworks. This study presents an innovative approach for obtaining ready-to-use electrospun mats composed of Agar nanofibers incorporating silver and gold nanoparticles. Electrospinning, a cost-effective and simple technique that utilizes a high electric field [1], enables the fabrication of highly porous mats with a high surface-to-volume ratio. These features facilitate controlled solvent release, easy removal from treated surfaces, and enhanced cleaning and disinfection capabilities through the incorporation of functional nanomaterials [2]. Aqueous solutions containing Agar, a polysaccharide derived from algae [3], and the co-spinning agent poly(ethylene oxide) (PEO, 300K g/mol) were prepared at a total concentration of 3% w/v (50:50 Agar/PEO ratio) and used as a polymeric matrix for the in-situ synthesis of the metal nanoparticles through a green bottom-up approach that eliminates the need for reducing agents. The nanoparticles-containing suspensions were characterized by rheological, spectroscopic, and TEM analyses to assess viscosity, polymer-filler interactions, and nanoparticles morphology and stability on time before being processed by electrospinning. Once prepared, the electrospun mats were characterized via Atomic Force Microscopy (AFM) and Field-Emission Scanning Electron Microscopy (FE-SEM) to evaluate surface roughness and nanocomposite morphology, mechanical testing, contact angle measurements to assess wettability and hydrophilicity, and SEM-EDX analysis to study the nanoparticles distribution within the polymeric matrix. Leveraging the unique antibacterial and antifungal properties of noble metal nanoparticles [4], these nanocomposite mats were successfully tested against selected bacterial and fungal species. The results obtained pave the way for the development of nanostructured mats that could revolutionize current disinfection and cleaning methodologies through their peculiar physico-chemical properties. Future studies will explore the thermoplasmonic properties of mat with gold nanoparticles for biofilm eradication, offering a novel strategy for artwork conservation.