Fragrant chitosan nanospheres: Controlled release systems with physical and chemical barriers

Existing fragrance controlled release systems are either based on a physical barrier, such as entrapment of the fragrant molecules inside the micro- or nano-spheres, or a chemical barrier, such as labile chemical bonds. Here, we propose a system with a combination of the two approaches but fabricated via a simple surfactant free one step process using biodegradable chitosan polymer. The fabrication process involves a chemical reaction to covalently link the fragrant aldehydes with the amine functionalities of the N-succinylchitosan (NS-chitosan) carriers that simultaneously leads to an ultrasonic aided reorganization of the spheres in such a way that the grafted entities are at the particles’ core. Localization of the grafted imine moieties at the core of the imine-NS-chitosan particles was confirmed by X-ray photoelectron spectroscopy (XPS) analysis. The obtained fragrant chitosan nanospheres not only showed up to 85-fold fragrance prolongation but also dispersed well in water.