DNA BINDING TO ELECTROPOLYMERIZED POLYPYRROLE: THE DEPENDENCE ON FILM CHARACTERISTICS

• Published in: Journal of macromolecular science. Part A, Pure and applied chemistry Pure and applied chemistry, 2001-01, Vol.38 (12), p.1245-1258
• Main Authors: Minehan, Daniel S., Marx, Kenneth A., Tripathy1†, Sukant K.
• Format: Article
• Language: English
• Subjects: Adsorption; Aging of materials; Applied sciences; Charge defects; Conductivity; Current density; DNA; DNA binding; Doping (additives); Electric conductivity; Electropolymerization; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Polypyrrole; Properties and characterization; Surface properties; Thin films
• ISSN: 1060-1325; 1520-5738
• DOI: 10.1081/MA-100108381

Evidence is presented that suggests the binding of DNA to electropolymerized polypyrrole (PPy) is directly related to the presence of positive charge carriers in PPy. The adsorption rate of short radiolabelled ∅X174 DNA fragments (average size 300 bp) onto thin films of electroxidized PPy doped with p-toluene sulfonate was found to vary as a function of: film storage conditions, film age, electrochemical reduction, but not synthesis current density. DNA bound more readily to films stored under dry conditions. DNA binding varied only slightly with the current density used during PPy electropolymerization. The DNA binding levels were significantly reduced with increasing PPy film age. This observation correlated qualitatively, but not quantitatively, with the known loss of PPy conductivity and charge defects with aging. DNA adsorption levels fell off far more rapidly with film age than does conductivity. Oxidized PPy films bound DNA at a higher rate than films which had been reduced subsequent to electroxidative synthesis, thereby removing a large fraction of the surface positive charge defects. These results support the idea that DNA binding is brought about by the presence of positive charge defect carriers in the PPy film. † Deceased.