Assessment of cellular toxicity of TiO2 nanoparticles for cardiac tissue engineering applications

Because of the increased use of titanium dioxide (TiO2) nanoparticles (NPs) in tissue engineering (TE), and in new constructs for cardiac TE, their effect was studied on three relevant cell types: Adult rat ventricular cardiomyocytes, human embryonic stem cell-derived cardiomyocytes (hESC-CM) and fibroblasts. For adult rat myocytes, 10 microg/mL TiO2 NPs showed no significant effect on myocyte survival over 24 h or acute myocyte contractility. Increasing the concentration to 100 microg/mL was seen to reduce contraction amplitude (p < 0.05). For hESC-CM, 10 microg/mL TiO2 reduced the beating rate significantly by 24 h. No arrhythmias or cessation of beating were observed in either cell type. Culturing fibroblasts in 5-150 microg/mL TiO2 significantly reduced cell proliferation at day 4 and increased cell death. We conclude that there may be modest but potentially adverse effects of TiO2 NPs if used in fast degrading polymers for myocardial tissue engineering (MTE) applications.