Double-layered hyaluronic acid/stearic acid-modified polyethyleneimine nanoparticles encapsulating (-)-gossypol: a nanocarrier for chiral anticancer drugs.

This study aimed to enhance the water solubility and antitumor efficacy of (-)-gossypol. Polyethyleneimine conjugated with stearic acid (PgS) was used for loading and protecting (-)-gossypol through hydrogen bonding. Double-layered hyaluronic acid (HA)-modified PgS nanoparticles encapsulating (-)-gossypol [(-)-G-PgSHAs] were prepared through a two-step fabrication process. The nanoparticles possessed a uniform spherical shape with a dynamic size of 110.9 ± 2.4 nm, which was determined through transmission electron microscopy and dynamic light scattering analysis. The encapsulation efficiency and drug-loading capacity of (-)-G-PgSHAs were 72.6% ± 3.1% and 9.1% ± 0.42%, respectively. The IR spectra of the samples confirmed the protection effect of hydrogen bonding on the optical activity of the encapsulated (-)-gossypol. (-)-G-PgSHAs exhibited a controlled and tumor-specific release because of the high expression of HAase in the tumor region. The tumor-targeting feature of PgSHAs due to HA-receptor mediation was confirmed by in vitro cell uptake and in vivo near infrared fluorescence imaging. The in vitro test showed that the (-)-G-PgSHAs had similar cytotoxicity to free (-)-gossypol and was smaller than that of the encapsulated (±)-gossypol [(±)-G-PgSHAs]. The in vivo study of the anti-cancer effect of (-)-G-PgSHAs revealed that (-)-G-PgSHAs had a more enhanced tumor-suppression effect and reduced systemic toxicity compared with free (-)-gossypol and (±)-G-PgSHAs (P < 0.05). Therefore, PgSHA was a useful (-)-gossypol nanocarrier that exhibits high biocompatibility, tunable release of drug, and tumor-targeting characteristics for cancer treatment. In addition, this double-layered nanocarrier provided novel strategies for the encapsulation of other chiral drugs.