Insight into the role of copper-based materials against the coronaviruses MHV-3, a model for SARS-CoV-2, during the COVID-19 pandemic.

Coating high-touch surfaces with inorganic agents, such as metals, appears to be a promising long-term disinfection strategy. However, there is a lack of studies exploring the effectiveness of copper-based products against viruses. In this study, we evaluated the cytotoxicity and virucidal effectiveness of products and materials containing copper against mouse hepatitis virus (MHV-3), a surrogate model for SARS-CoV-2. The results demonstrate that pure CuO and Cu possess activity against the enveloped virus at very low concentrations, ranging from 0.001 to 0.1% (w/v). A greater virucidal efficacy of CuO was found for nanoparticles, which showed activity even against viruses that are more resistant to disinfection such as feline calicivirus (FCV). Most of the evaluated products, with concentrations of Cu or CuO between 0.003 and 15% (w/v), were effective against MHV-3. Cryomicroscopy images of an MHV-3 sample exposed to a CuO-containing surface showed extensive damage to the viral capsid, presumably due to the direct or indirect action of copper ions.

Smart Textiles with Self-Disinfection and Photothermochromic Effects.

Self-disinfecting textile materials employing combined photodynamic/photothermal effects enable the prevention of microbial infections, a property that has great potential in healthcare applications. However, smart textiles with stimulus responses to ambient temperature are marvelous materials for enhancing their photothermal applications with additional functions. It is still challenging to realize vivid and contrasting color changes as temperature indicators. Herein, through the in situ growth of PCN-224 metal-organic frameworks (MOFs), the electrospraying of a Ti3C2 MXene colloid, and the screen printing of a thermochromic dye, a smart photothermochromic self-disinfecting textile has been fabricated. An antibacterial inactivation study revealed 99.9999% inactivation toward gram-negative (Escherichia coli ATCC 8099) and gram-positive (Staphylococcus aureus ATCC 6538) bacteria in 30 min. A mechanism study revealed that light-driven singlet oxygen and heat are the main reasons for bacterial inactivation. Interestingly, the fabrics presented photothermal effects not only under a handheld 780 nm NIR laser but also under visible Xe lamp (λ ≥ 420 nm) illumination. The color of the fabrics (S-CF@PCN0.08) changed completely from dark green to dark red when the temperature exceeded 45 °C under Xe lamp illumination. Furthermore, the photothermochromic effect occurred in just 1 s under a 780 nm laser. Taken together, this smart photothermochromic self-disinfecting textile permits a new way to feedback the timely signal of temperature by color change and provides novel insights into the development of self-disinfecting textiles.