Aromatherapy is widely used in the treatment of diseases of the central nervous system, such as depression and anxiety. However, the rapid and uncontrolled release of aroma weakens the effects of aromatherapy. In this study, zwitterionic polymer-based nanoparticles encapsulated with linalool were prepared to improve the regulation of the central nervous system. First, the nanoparticles were modified with positive charges to adhere to the surface of silk via electrostatic interactions between the cationic nanoparticles and anionic silk. Besides, the fragrance was sustainably and controllably released from the nanoparticles. The effects of polymerization degree, polymer structure, and zeta potential on encapsulation efficiency, adhesion efficiency, and release profiles of linalool were then explored. The results showed that the linalool-encapsulated nanoparticles had the best performances of encapsulation, adhesion and release of fragrance when the polymerization degrees of hydrophilic block and hydrophobic block were 20 and 5, respectively. In addition, open field tests evaluated the regulation of nanoparticles on the central nervous system at the behavioral level. Measurements of dopamine, acetylcholine, and γ-aminobutyric acid expressions explored the mechanism of moderating effects on the central nervous system at the molecular level.
Keywords: adhesion of fragrance; encapsulation of fragrance; regulation of central nervous system; sustained and pH-sensitive release of fragrance; zwitterionic polymer-based nanoparticles.