Drug co-loading and pH-sensitive release core–shell nanoparticles via layer-by-layer assembly

Abstract

Multifunctional core–shell nanoparticles are widely used for biomedical and catalytic applications. In this work, bilayers of chitosan (Cs) and phosphorylated polyvinyl alcohol (PPVA) were sequentially deposited on 3-Aminopropyltri-ethoxysilane-modified SiO₂ nanoparticles via layer-by-layer electrostatic self-assembly. The good spherical shape and size distribution were observed by DLS and transmission electron microscope analysis. 7-Hydroxycoumarin (7-HC) and rhodamine B (RhB) as model drugs were loaded in the core and shell of the nanoparticles separately. Confocal laser scanning microscopy shows the core–shell structure of HC-SiO₂(PPVA/Cs)_n-RhB nanoparticles and the embedded location of 7-HC and RhB. The pH-sensitive release investigation of RhB indicates that the release profiles of RhB from HC-SiO₂(PPVA/Cs)₃PPVA-RhB core–shell nanoparticles are totally different at pH values of 2.0, 7.4, and 9.2. These results predict that the multifunctional nanoparticle SiO₂(PPVA/Cs)_n has a great potential for drug delivery.

Keywords:

• chitosan
• phosphorylated polyvinyl alcohol
• layer-by-layer assembly
• silica
• core–shell nanoparticle
• pH sensitive
• co-loading

Funding

This work is supported by the National Nature Science Foundation of China [grant number 51073119], [grant number 31271016]; Ministry of Science and Technology of China [grant number 2013DFG52040].