title: The pH stimulated reversible loading and release of a cationic dye in a layer-by-layer assembled DNA/PAH film.
abstract: Through the layer-by-layer (LbL) deposition method, DNA was assembled into an ultrathin film with a cationic poly(allylamine hydrochloride) (PAH). The loading and release of a typical cationic dye, 5, 10, 15, 20-tetrakis(4-N-methylpyridyl)porphine-tetra-(p-toluenesulfonate) (TMPyP), in the DNA/PAH films were investigated. It has been found that the LbL-assembled DNA/PAH film was very stable in both acidic and alkaline solutions. Stimulated by the pH change of the dye solution, the dye can be easily loaded into or released from the DNA/PAH film. In an alkaline solution, the dye could be rapidly loaded into the DNA/PAH film at room temperature, while in an acidic solution, the dye could be rapidly released. The mechanism of such pH-stimulated loading and release in the DNA/PAH film was discussed. It was further observed that the loading and release of the dye in the DNA/PAH film was reversible upon pH change and the process could be repeated many times.
authors.affiliation: CAS Key Laboratory of Colloid and Interface Science, Center for Molecular Science, Institute of Chemistry, CAS, Beijing 100080, People's Republic of China.
authors.forename: Siguang
authors.initials: S
authors.lastname: Jiang
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Chen
authors.forename: Minghua
authors.initials: M
authors.lastname: Liu
mesh_terms: D002412:Cations / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008567:Membranes, Artificial; D015394:Molecular Structure; D011073:Polyamines / Q000737:chemistry*; D011166:Porphyrins / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D002412:Cations; D008567:Membranes, Artificial; D011073:Polyamines; D011166:Porphyrins; C063994:polyallylamine; C021096:tetra(4-N-methylpyridyl)porphine; D004247:DNA