Cytotoxic consequences of Halloysite nanotube/iron oxide nanocomposite and iron oxide nanoparticles upon interaction with bacterial, non-cancerous and cancerous cells.

Cytotoxic effects of iron oxide (Fe3O4) nanoparticles and Halloysite nanotube/iron oxide (HNT/Fe3O4) nanocomposite are compared based on their interaction with Gram-negative bacteria Escherichia coli and Gram-positive bacteria Bacillus subtilis. Similarly, the action of these two nanomaterials on non-cancerous Vero cell lines and human lung cancerous (A-549) cell lines are compared. The cytotoxicity studies on Fe3O4 nanoparticles and HNT/Fe3O4 nanocomposite showed difference in the rate of killing of bacterial cells. This is reflected in differential cell growth, cell membrane integrity loss, lactate dehydrogenase (LDH) release and reactive oxygen species (ROS) production. These factors are measured over a range of concentrations of Fe3O4 nanoparticles and HNT/Fe3O4 nanocomposite and at specified time intervals, to test if there is any statistically significant difference between the toxicity of the two nanomaterials. Between the two nanomaterials, HNT/Fe3O4 nanocomposite is found to be less toxic to bacterial cells than Fe3O4 nanoparticles. HNT, when attached to the Fe3O4 nanoparticles, changes their surface characteristics and suppresses their inherent toxicity on bacteria. In the study on the effect on cell lines, Fe3O4 nanoparticles and HNT/Fe3O4 nanocomposite are both seen to be biocompatible with Vero cell lines. However, HNT/Fe3O4 nanocomposite showed more cytotoxicity than Fe3O4 nanoparticles on A-549 cell lines.