In vitro acute inhalation toxicity for TiO2 (GST) using 3D human tissue model (EpiAirwayTM).

The present study was performed to screen in vitro potential acute inhalation toxicity using an EpiAirwayTM tissue model (human tracheal/bronchial tissue) for the nano-sized titanium dioxide, GST manufactured as a photocatalyst through of sludge recycling and to compare with P-25 a commercialized photocatalytic material. According to the protocol provided by in vitro tissue manufacturer, the GST was exposure to the tissue for 3 hours in 450, 500, 650, 850 mg/mL concentration after preliminary dose range finding study and then tissue viability (%, IC75) was calculated using the MTT assay. Besides, the histopathological observation was performed to compare to the MTT assay. As a result of study, IC75 could not be confirmed at 850 mg/mL in both GST and P-25 and the grade was confirmed to be IC75> 600 mg/mL in vitro model tissue category. Therefore, it was considered that the GHS category could be classified as 'No classification' in screening method for potential acute inhalation toxicity. Also, not the morphological effects of epithelial cells in tissue model were observed compared with the vehicle control and histological findings were similar to the results of MTT Viability assay. Based on these results, the potential acute inhalation toxicity for GST produced through sludge recycling using in vitro tissue model inhalation toxicity showed that it could be non-hazardous substance. However, further study (in vivo study, etc.) is thought to be needed to ascertain whether GST is a toxic effect or safe.