Biocompatibility of colloidal polypyrrole

The excellent electroconductive properties of polypyrrole (PPy) predetermine its use as cell-instructive or bio-sensing biomaterial. PPy has potential for application in a physiological environment, and here the cytotoxicity, antioxidant capacity, modulation of neutrophil oxidative burst, antibacterial activity of colloidal PPy stabilized with polyvinylpyrrolidone (PVP), and long-term stability under physiological conditions are reported. Besides, long-term stability under physiological conditions is also provided. The formation of PPy/PVP colloid was proven by UV-Vis and IR spectroscopy, and its morphology and particle size were detected. The results of cytotoxicity studies show that the safe PPy concentration in colloidal particles for biomedical usage is <= 200 mu g mL-1. In these concentrations, the PPy/PVP also exhibits excellent antioxidant properties and modulates the immune response. The minimal inhibitory concentration of 234 mu g mL-1 was determined against Staphylococcus aureus and Escherichia coli, respectively. The low cytotoxicity and bioactivity of the colloidal PPy/PVP demonstrate their long-term potential for a variety of applications