Immune Gene Expression Modulation and In Vitro Inhibitory Effect of TiO2 Nanoparticles Under UV Irradiation on Viral Necrosis Virus

This study examines the potential in vitro application of different concentrations of titanium dioxide (TiO2) nanoparticles (NPs) irradiated with UV light for the sanitation of recirculating aquaculture systems (RASs) and their antiviral activity. The diverse effects of Nodavirus on immune gene expression (i.e., pro-inflammatory and anti-inflammatory genes, cellular response genes, humoral response genes, and stress genes) were studied using RT-qPCR (Reverse Transcription Quantitative Polymerase Chain Reaction). In addition, the viability and cytopathic effect in E-11 fish cells were also investigated. The results obtained did not show a clear cytopathic effect under the reversed-phase microscope observation at different TiO2 concentrations. A significant decrease in viral coat protein gene expression was observed when using 2.5 and 1.25 g/L TiO2 suspensions under UV irradiation. TiO2 at 1.25 g/L induced an inflammatory response to Nodavirus by increasing the expression of all target genes. Thus, this work suggests that TiO2 NPs can strengthen the immune system of fish to fight virus infection and make aquaculture a greener and more sustainable activity.