14 A comparative biodistribution and toxicity study of single and multi-component nanomaterials: TiO2, SiC, and SiC@TiO2

Abstract Background With the increasing integration of nanomaterials (NMs) into daily life, their technological advantages have become evident. However, their intricate interactions with biological systems introduce complexities that can lead to unpredictable toxicological outcomes. This study investigated the in vivo toxicokinetics and toxicodynamics of single- and multi-component NMs composed of silicon carbide (SiC), titanium dioxide (TiO2), and a SiC@TiO2 composite, along with a physical mixture of SiC and TiO2 in the same ratio as the composite. Rats were exposed to these materials via single intratracheal instillation, and biological responses were assessed over time (1 h to 28 d) to identify the no-observed-adverse-effect level (NOAEL). Results All NMs induced minimal structural alterations in lung tissue and prompted varying degrees of inflammatory cell infiltration. Over time, translocation from the lungs to secondary organs (heart, spleen, liver, kidney) was observed, with distinct distribution patterns between Si- and Ti-containing NMs. Bronchoalveolar lavage fluid analysis revealed a minimal to mild inflammatory response that evolved in a time-dependent manner, even at NOAEL exposure levels, suggesting delayed-onset biological effects. Conclusions SiC@TiO2 demonstrated a reduced pulmonary toxicological profile relative to its single-component counterparts, likely due to antagonistic effects between its constituents. These findings highlight the need to assess multicomponent nanomaterials as distinct entities and suggest that rational material design may help mitigate adverse biological effects, supporting safer nanotechnology development.