IMPEDANCE STUDIES OF SURFACTANT-POLYION-CHOLESTEROL FILMS

Studies of the temperature dependence of electrical impedance showed t hat molecular organization of films of dioctadecyldimethylammonium bro mide (DODAB) and sodium poly(styrenesulfonate) (PSS) or the ionomer Na tion on pyrolytic graphite electrodes was improved by annealing in wat er. Films prepared by dipping Nafion-coated electrodes into DODAB disp ersions bud similar phase transition temperatures to water-annealed ca st DODAB-Nafion films. The work also demonstrated the influence of cho lesterol content on the impedance and phase transition properties, of the films. Impedance changes upon binding of bovine serum albumin (BSA ) to anti-BSA in DODAB-Nafion films suggest that preparation methods a nd optimized amount of cholesterol an important for applications of im pedance-based detection of. macromolecular binding events using these film materials.