Characterization of coal fly ash nanoparticles and their induced in vitro cellular toxicity and oxidative DNA damage in different cell lines.

Coal combustion generates considerable amount of ultrafine particles and exposure to such particulate matter is a major health concern in the developing countries. In this study, we collected nano sized coal fly ash (CFA) and characterized them by scanning electron microscope-energy dispersive X-ray analysis (SEM-EDX), particle size analyzer (PSA) and transmission electron microscope (TEM), and investigated its toxicity in vitro using different cell lines. The imaging techniques showed that the coal fly ash nanoparticles (CFA-NPs) are predominately spherical shaped. The analyses have revealed that the CFA-NPs are 7-50 nm in diameter and contain several heavy metals associated with CFA particles. The studies showed significant amount of toxicity in all cell lines on treatment with CFA-NPs. The cytotoxicity and oxidative DNA damage caused by CFA-NPs were determined by inhibition of cellular metabolism (MTT), total intracellular glutathione (GSH), reactive oxygen species (ROS) and DNA fragmentation in cultured cell lines (Chang liver, HS294T and LL29). The cellular metabolism was inhibited in a dose-dependent manner in CFA-NPs treated cell lines. The CFA-NPs induced ROS and decreased the total intracellular glutathione with increased dose. Further, the CFA-NPs treated cells showed severe DNA laddering as a result of DNA fragmentation.