[Introduction] Nanomaterials (NMs) are known to have unique physicochemical properties (PCPs), which make their functions and activities very different. In our daily life, they are widely used in pharmaceuticals, industrial products, and other daily necessities. On the other hand, there is an urgent need to develop toxicity testing methods for NM to assess its effects on human health internationally accurately. In this study, PCPs of various NMs and the THP-1 cell activation-related indicators by the h-CLAT method (EC150 and EC200) were validated using in silico. [Method] The various NM test substances used in this study were partly provided by domestic manufacturers and JRC Nanomaterials Repository (Ispra, Italy). Their PCP values were collected from new measurements in addition to existing references. Toxicity evaluation was conducted by the in vitro h-CLAT method (OECD TG442E) in accordance with the OECD test guidelines for skin sensitization. The dataset above was formatted to be suitable for statistical analysis and processed using SIMCA-P. [Results and Discussion] PCPs and h-CLAT test results verified the association of the variables using principal component analysis. In addition, the correlations between each PCP variable and indicators of h-CLAT test results (EC150, EC200, and their scaled values) were also verified. The results suggest that log-transformed values (e.g., pEC150 = -logEC150) are new parameters more adapted to the present analysis, and pEC200, in particular, is helpful as an indicator of antigen presentation activation by NMs.
