Zein-Functionalized MCM-41 Silica Nanoparticles with Enzyme-Responsive for Controlled Release in Antibacterial Activity

This research provided a novel enzyme-responsive antimicrobial carrier aiming at overcoming the volatile loss of active antibacterial components, by employing mesoporous silica nanoparticles (MCM-41) as the matrix of encapsulation and Zein as the molecular gate. Since Zein could be consumed by bacteria, Zein-functionalized MCM-41 acted as an enzyme-responsive gate and improved the controlled-release capacity. The results showed that the amount of capsaicin released from Zein-functionalized MCM-41 without bacteria was quite low compared with the essential oils liberated with bacteria. This validated that the delivery of capsaicin was hampered by Zein and the existence of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) promoted the release of encapsulated cargo. The release rate of capsaicin in Zein-functionalized MCM-41 climbed with the growth velocity of bacteria. These functions were realized in the form of controlled diffusion of essential oils encapsulated in MCM-41 by electrostatic interaction, and Zein was performed by both covalent bonding interaction and electrostatic interaction. Zein-functionalized MCM-41 was 2.4 times more effective in killing E. coli and 1.2 times more effective in inhibiting S. aureus than an equal amount of free capsaicin, and possessed a long-lasting antibacterial activity. The responsive antimicrobial material might be used as a promising preservative in the food industry for antimicrobial activity enhancement.