Antibacterial effect of protease-responsive cationic eugenol liposomes modified by gamma-polyglutamic acid against Staphylococcus aureus

Abstract

Eugenol, as a natural antibacterial agent, has been widely studied for its inhibitory effect on the common food-borne pathogen Staphylococcus aureus (S. aureus). However, the widespread application of eugenol is still limited by its instability and volatility. Herein, γ-polyglutamic acid coated eugenol cationic liposomes (pGA-ECLPs) were successfully constructed by self-assembly with an average particle size of 170.7 nm and an encapsulation efficiency of 36.2%. The formation of pGA shell significantly improved the stability of liposomes, and the encapsulation efficiency of eugenol only decreased by 20.7% after 30 days of storage at 4 °C. On the other hand, the pGA layer can be hydrolyzed by S. aureus, achieving effective control of release through response to bacterial stimuli. The application experiments further confirmed that pGA-ECLPs effectively prolonged the antibacterial effect of eugenol in fresh chicken without causing obvious sensory effects on the food. The above results of this study provide an important reference for extending the action time of natural antibacterial substances and developing new stimuli-responsive antibacterial systems.

Keywords:

• Polyglutamic acid
• cationic liposome
• layer-by-layer self-assembly
• S. aureus
• eugenol

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research project was financially supported by the State Key Laboratory of Utilization of Woody Oil Resource (Grant no. 2019XK 2002), National Natural Science Foundation of China (Grant no. 31972172), Natural Science Foundation of Jiangsu Province (Grant no. BK20201417) and Jiangsu Province Research Fund (Grant no. JNHB-131).