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Biofilm formation in common public places and hospitals is of great concern. Active antimicrobial coatings can prevent the formation of bacterial biofilms and the spreading of primary and secondary infections caused by contagious bacteria and viruses. In the present work, we report a simple spray coating process using copper oxide (CuO) nanoparticles (NPs) dispersed in a titanium dioxide (TiO 2 ) sol, where CuONPs act as the active antimicrobial agent and TiO 2 as the inorganic binder. Homogeneous CuONPs/TiO 2 coating was obtained on polypropylene substrates by spraying the CuO/TiO 2 sol using a commercial air gun, followed by drying at 80 °C. The amount of CuONPs loading in the coating was adjusted by controlling the number of coated layers. CuONPs and CuONPs/TiO 2 coatings were characterized by XRD, BET, X-ray fluorescence spectroscopy, AFM, and field emission scanning electron microscopy techniques. All of the coated films showed dual activity, i.e., antimicrobial and superhydrophobicity. A high bactericidal effect against both Escherichia coli and Staphylococcus aureus was observed for the coated substrates. Coatings with higher CuONPs showed greater antibacterial activity, reaching R value >6, and no bacterial colonies were detected after 24 h of incubation. An increasing trend of water contact angle was observed with the increasing amount of CuONP loading., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

In our continuing search for new polymer composites with antimicrobial activity, we observed that even unmodified epoxy resins exhibit significant activity. Considering their widespread use as starting materials for the realization of multifunctional nanocomposites with excellent chemical and mechanical properties, it was deemed relevant to uncover these unexpected properties that can lead to novel applications. In fact, in places where the contact with human activities makes working surfaces susceptible to microbial contamination, thus jeopardizing the sterility of the environment, their biological activity opens the way to their successful application in minimizing healthcare-associated infections. To this end, three commercial and widely used epoxy resins (DGEBA/Elan-TechW 152LR, 1 ; EPIKOTE TM Resin MGS ® /EPIKURE TM RIM H 235, 2 and MC152/EW101, 3 ) have been investigated to determine their antibacterial and antiviral activity. After 24 h, according to ISO 22196:2011, resins 1 and 2 showed a high antibacterial efficacy (R value > 6.0 log reduction) against Staphylococcus aureus and Escherichia coli . Resin 2 , prepared according to the ratio epoxy/hardener indicated by the supplier (sample 2a ) and with 10% w / w hardener excess (sample 2b ), exhibited an intriguing virucidal activity against Herpes Simplex Virus type-1 and Human Coronavirus type V-OC43 as a surrogate of SARS-CoV-2.