Fabrication of Polypyrrole Nanoparticles via Different Polymerization Methods and Their Cytotoxicity Evaluation

Abstract

The cellular effect of polypyrrole (PPy) nanoparticles with similar geometry (size and shape) was scrutinized by cellular uptake and in vitro cytotoxicity assessments in human lung epithelial A549 cell and human embryonic kidney epithelial HEK293 cells. PPy1~4 nanoparticles with a diameter of ca. 50 nm and spherical shape were successively fabricated by four different polymerization methods, two dispersion polymerization and two microemulsion polymerization. Cellular uptake of PPy1~4 nanoparticles in both cell lines was evaluated by transmission electron microscopy. Cytotoxic effects were systemically investigated using cell viability, reactive oxygen species production, apoptosis/necrosis measurement, and live-cell microscopy. PPy3 nanoparticles using dodecyltrimetylammonium bromide exhibited the highest levels of toxicity in both cell lines, because of the cellular effects of unique physicochemical properties. In addition, viability in both cell lines was concentration- and cell-dependent with the nanoparticles. These findings may provide the methods-dependent nanotoxicity and uptake of PPy nanoparticles, which could be useful in their application toward biomedical and bioelectronics fields.