Antiviral papers generated from copper-supported TEMPO-oxide cellulose: Antiviral surface objective performance evaluation and underlying mechanisms

Paper can be directly touched by many unspecified people, representing a potential vector for contact transmission; however, papers with high antiviral activity are yet to be reported. Herein, copper-supported TEMPO-oxidized cellulose (Cu-TOC) was produced by adsorbing copper ions onto TEMPO-oxidized cellulose, and antiviral papers (AVPs) were developed from Cu-TOC. Contact with water rapidly released copper ions from AVPs, yielding 137 µg/dL copper ion solution after 3 min of elution. This copper-ion solution exhibited moderate antiviral activity, reducing influenza virus (IFV), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and feline calicivirus (FCV) by approximately 90% after a 30-min reaction. Moreover, copper ions significantly shortened the survival times of these viruses on paper in a concentration-dependent manner. Compared with that on plain paper with the same physicochemical properties, the survival time of viruses on AVPs was significantly shortened; the survival-time shortening rates for IFV, SARS-CoV-2, and FCV were 63.3%–88.4%, 89.4%–98.8%, and 89.8%–99.9%, respectively. Thus, the development of versatile AVPs from Cu-TOC and elucidation of the underlying antiviral mechanism were achieved. These AVPs can significantly shorten virus survival time and prevent contact transmission. Furthermore, the performance of antiviral surfaces could be accurately evaluated using survival time (or half-life) as an index parameter for antiviral activity.