Biocompatibility and antioxidant activity of polypyrrole nanotubes

• Polypyrrole nanotubes of different diameter have been synthesized.
• Nanotubes of smaller diameter are obtained at higher CTAB concentration.
• Nanotubes having smaller diameter show enhanced antioxidant activity.
• Synthesized nanotubes show biocompatibility upto a concentration of 2.5 mg/ml.

In the present study antioxidant activity of polypyrrole nanotubes of varying diameter has been investigated. The haemolysis prevention efficiency of the polypyrrole nanotube having highest antioxidant activity has also been studied. Polypyrrole nanotubes have been prepared by chemical polymerization method using FeCl3 as oxidant with methyl orange (MO) and Cetyl trimethylammonium bromide (CTAB). Structural properties of polypyrrole nanotubes with varying CTAB concentrations have been studied by X-ray diffraction pattern and high resolution transmission electron microscopy (HRTEM). The HRTEM micrographs of polypyrrole nanotubes show significant decrease in diameter upon increase in CTAB concentration. Micro-Raman spectroscopy has been performed to understand the polymer conformation. We demonstrate the antioxidant activity of polypyrrole nanotubes by DPPH free radical assay. The biocompatibility of the polypyrrole nanotubes have been investigated via haemolysis assay.