Impact of Nanoparticle-Based TiO₂ Surfaces on Norovirus Capsids and Genome Integrity

Human noroviruses (HuNoVs) are among the main causes of acute gastroenteritis worldwide. HuNoVs can survive for several days up to weeks at room temperature in the environment, on food, and on food handling and processing surfaces. As a result, this could lead to viral spread through the ingestion of food in contact with contaminated surfaces. The development of stable surface materials with antiviral activity might be useful to reduce viral outbreaks. Metal-based compounds, including photoactivated titanium nanoparticles (TiO₂ NPs), are known for their antiviral activity. In this study, we tested the impact of 2000 µg/mL TiO₂ NPs, with or without UV activation, on HuNoV GII and murine norovirus. Their recovery rates were reduced by 99.6%. We also evaluated a new TiO₂ NP-coating process on a polystyrene surface. This process provided a homogenous coated surface with TiO₂ NPs ranging between 5 nm and 15 nm. Without photoactivation, this TiO₂ NP-coated polystyrene surface reduced the recovery rates of intact HuNoV GII by more than 94%. When a capsid integrity treatment with PtCl₄ or a longer reverse transcription polymerase chain detection approach was used to evaluate virus integrity following contact with the TiO₂ NP-coated polystyrene, the HuNoV GII recovery yield reduction varied between 97 and 100%. These results support the hypothesis that TiO₂ NP-coated surfaces have the potential to prevent viral transmission associated with contaminated food surfaces.