Controlled loading and release of methylene blue in layer-by-layer assembled polyelectrolyte films

The layer-by-layer (LbL) assembled multilayer films are widely used in the biomedical field for the controlled drug delivery. Here, multilayer films were assembled by LbL technique through alternating deposition of poly(diallyldimethylammonium chloride) (PDDA) and poly(acrylic acid) (PAA) on glass slides. Methylene blue (MB) was used as a model drug to investigate the loading and release ability of the multilayer films. The result showed that the loading rate and loading amount of MB were greatly influenced by ionic strength and pH value of the dye solution, and the release rate of MB was also controlled both by ionic strength and pH value of immersing solution. The result also testified that the films had good reversibility of drug loading and release. It suggested that the PDDA/PAA multilayer films had a potential application in drug delivery, especially in drug burst release.

► PDDA/PAA multilayer film was fabricated via LbL technique.
► The loading of organic molecules methylene blue (MB) was influenced by ionic strength and pH value.
► The release of MB from the film was controlled both by ionic strength and pH value.
► The reversible property of the film towards MB loading and release was observed.
► The film has great potential applications in drug delivery and controlled release.