DNA adsorption onto conducting polypyrrole

Deoxyribonucleic acid (DNA) adsorption onto chemically synthesized polypyrrole powders was investigated as a function of pH, buffer nature, ionic strength and substrate nature. DNA adsorption was found to be in the range of 0.13–0.55 mg m−2 for the conditions under investigation. Strong DNA adsorption was obtained at low pH and high ionic strength. The decreasing order of adsorption as a function of the native dopant was nitrate, chloride>sulfate. The isotherms were found to be of the Langmuir type or sigmoid, depending on the combination of (at least) substrate and buffer natures. Affinity constants determined using Scatchard and Hill plots were found to be as high as 106 M−1.