Polydopamine-cladded montmorillonite micro-sheets as therapeutic platform repair the gut mucosal barrier of murine colitis through inhibiting oxidative stress

Abstract

Montmorillonite (MMT), a layered aluminosilicate, has a mucosal nutrient effect and restores the gut barriers integrity. However, orally administrating MMT is not effective to combat the reactive oxygen species (ROS) and alleviate the acute inflammatory relapse for colitis patients. Herein, polydopamine-doped montmorillonite micro-sheets (PDA/MMT) have been developed as a therapeutic platform for colitis treatment. SEM and EDS analysis showed that dopamine monomer (DA) was easily polymerized in alkaline condition and polydopamine (PDA) was uniformly cladded on the surface of MMT micro-sheets. The depositing amount of PDA was reaching to 2.06 ​± ​0.08%. Moreover, in vitro fluorescence probes experiments showed that PDA/MMT presented the broad spectra of scavenging various ROS sources including •OH, •O2−, and H2O2. Meanwhile, the intracellular ROS of Rosup/H2O2 treated Caco-2 ​cell was also effectively scavenged by PDA/MMT, which resulted in the obvious improvement of the cell viability under oxidative stress. Moreover, most of orally administrated PDA/MMT was transited to the gut and form a protective film on the diseased colon. PDA/MMT exhibited the obvious therapeutic effect on DSS-induced ulcerative colitis mouse. Importantly, the gut mucosa of colitis mouse was well restored after PDA/MMT treatment. Moreover, the colonic inflammation was significantly alleviated and the goblet cells were obliviously recovered. The therapeutic mechanism of PDA/MMT was highly associated with inhibiting oxidative stress. Collectively, PDA/MMT micro-sheets as a therapeutic platform may provide a promising therapeutic strategy for UC treatment.

Keywords

• Montmorillonite
• Polydopamine
• Ulcerative colitis
• Oxidative stress
• Gut mucosal barrier