| This research explores the possibility of controlling the properties of polymer solutions containing ferrocene-based redox-active surfactants using chemical and electrochemical methods to alter the oxidation state and, consequently, the self-association of the surfactant. Polymer-surfactant interactions require cooperative self-association of the surfactant, so changes in the oxidation state of the surfactant lead to changes in the aggregation behavior. Electrochemical and chemical control of the oxidation state of the surfactant hence provides a basis for in situ control of these solutions.; A redox-active surfactant, (11-ferrocenylundecyl)trimethylammonium bromide (FTMA), is used to alter the aggregate size (by measurements of dynamic light scattering, DLS) and clouding temperature of a cellulose-based polymer solution by electrochemical manipulation of the oxidation state, which changes the charge of FTMA from 0 (reduced) to +1 (oxidized). FTMA is also used to achieve in situ control of the conformation of DNA by electrochemical oxidation and chemical reduction of the surfactant, as shown by DLS.; The change in oxidation state of bis-(11-ferrocenylundecyl)dimethylammonium bromide (BFDMA), a double-tailed redox-active surfactant, led to changes in its aggregation, which is exploited when combining the lipid with DNA. Changes in the structure of BFDMA-DNA complexes dependent on lipid oxidation state were manifested as changes in the size, zeta potential, and microstructure of the DNA-lipid complexes. Lipoplexes prepared using DNA and reduced BFDMA form large multilamellar structures with varying zeta potential and complexes of DNA and oxidized BFDMA produce negatively charged aggregates with no well-defined structure. Furthermore, in situ changes in the aggregation behavior of the BFDMA-DNA complex are achieved by chemical reduction of the complex using a common intracellular reducing agent. |
