Zeolite beta in situ encapsulation of indole and its derivatives as controlled release formulations for antibacterial

Abstract Incorporation of guest organic molecules into zeolites has attracted much more attention for its broad application prospect in the fields of sensing, detection, antibacterial and so on. In this study, indole and its derivatives were successfully incorporated into zeolite beta through in situ encapsulation approach for the first time, which can overcome the drawbacks brought by traditional impregnation method and ion-exchange method. Taking indole as an example, the structure of obtained zeolite beta encapsulation of indole (indole@beta) has been well characterized to confirm the location of indole at zeolite inner channels. Thanking to confinement effect of zeolite, the release of indole from indole@beta complexes showed much slower release rate than that of indole/beta complexes, and along with pH sensitivity and temperature dependence. Such release behavior can be described with ritger-peppas model to obey the Fick's Laws of diffusion. In comparison with indole/beta coating, indole@beta coating exhibited more sustainable and effective antibacterial activity for its controlled release properties.