Integrated assessment of graphene oxide and graphitic carbon nitride nanoparticles: from synthesis to in vitro biological impact on zebrafish (Danio rerio) cell models.

Graphene and its derivatives have been increasingly explored for various biomedical applications. Despite their promising potential, the accelerated development and integration of these materials in medical technologies have raised important questions regarding their biocompatibility, toxicity, and overall safety within physiological systems. Graphene oxide (GO) and graphitic carbon nitride (g-C3N4) nanoparticles are widely studied for their strong adsorption and photocatalytic properties, making them effective materials for removing emerging contaminants from water and wastewater. In this study, we performed a detailed evaluation of the acute (24 h) cytotoxic effects of GO and g-C3N4 nanoparticles on DrG and DrF cells by assessing cell morphology, viability, mortality, and membrane integrity. GO exhibited minimal cytotoxicity under the tested conditions, with only a slight reduction in cell viability observed at 100 µg/mL concentrations due to dose-dependent oxidative stress. In contrast, g-C3N4 nanoparticles demonstrated significant cytotoxicity in both cell types, even at 40 µg/mL concentrations, inducing oxidative stress, elevated ROS production, mitochondrial dysfunction, and a marked decrease in cell viability. These findings underscore the importance of dose consideration in the design of GO-based biomedical applications and highlight the potential limitations of g-C3N4 in similar contexts. Overall, GO showed good biocompatibility, further supported by the favorable growth of cells on GO-coated substrates (50 µg/mL).