▎ 摘　　要

NOVELTY - Self-assembled nanosphere is a nano-scale core-shell structure having a drug as a core and a graphene oxide modified with chitosan as a shell. USE - The self-assembled nanospheres are useful in preparation of sustained-release food preservatives. ADVANTAGE - The self-assembled nanospheres have coating of a variety of hydrophobic drugs or volatile plant essential oils to achieve selective release of drugs and precise regulation of drug release rate. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for method for preparing the self-assembled nanosphere, which involves (a) immersing drug in the graphene oxide dispersion, unltrasonically-treating the mixture, freeze-drying it to form nanoparticles, (b) immersing the nanoparticles in the chitosan ethanol solution and freeze-drying to obtain nanospheres, (c) immersing nanospheres in the graphene oxide dispersion and the chitosan ethanol solution sequentially, and repeatedly for several times, and freeze-drying it to obtain multilayer coated nanospheres, and (d) immersing the multi-layer coated nanospheres in a photosensitive crosslinking agent, freeze-drying and irradiating with UV-rays to obtain self-assembled nanospheres.