Toxicological evaluation of industrially relevant graphene oxide using human hepatocytes and a murine model

Graphene oxide (GO) is a nanomaterial (NM) derived from graphite associated with oxygenated functional groups which confer catalytic and hydrophilic properties, enhancing its potential for industrial and therapeutic applications. This study aimed to integrate physicochemical characterization utilizing in vitro and in vivo toxicological assessments of GO developed by CTNANO-UFMG and CENPES/Petrobras for enhanced oil recovery. ATR-FTIR and TGA were used to characterize the chemical functional group profile. GO exhibited hydrodynamic diameters (HD) below 1 µm at different times. SEM analysis revealed mean equivalent circular diameters (ECD) of 11.37 (water) and 11.78 µm (DMEM). Concentrations of 5, 10, 50, 100, 250 or 500 µg/ml did not significantly affect HepG2 cell viability. Intraperitoneal GO administration (5, 12.5, 25 or 50 mg/kg) to BALB/c mice transiently reduced food and water intake and body weight. In pleural cavity lavage (PCL), number of leukocytes was decreased accompanied by lower levels of mononuclear cells and eosinophils but elevated neutrophils. In bronchoalveolar lavage (BAL), neutrophils were also increased. No significant changes were observed in IFN-γ and TNF levels in plasma, PCL, or BAL, although IL-6 was decreased in PCL. Serum AST levels were increased, and GO accumulated preferentially in liver, with additional deposits in adipose tissue adjacent to spleen and kidney. Histological changes and inflammatory infiltrates were observed in liver, spleen, and lungs. These findings indicate that GO induces mild local inflammatory responses and dose-dependent hepatic accumulation, indicating need for further studies with prolonged exposure periods to assess potential adverse effects and reversibility.