Therapeutic effect on protecting gut barrier. A Schematic of FMT in colitis rats. Faecal microbiota was fetched from healthy mice and transplanted to DSS-induced colitis mice. Reproduced with permission from Ref. [209]. Copyright 2020, Springer. B Fluorescent staining of ZO-1 and Occludin-3 in colon of mice in different groups. Scale bars are 50 μm. Reproduced with permission from Ref. [209]. Copyright 2020, Springer. C Schematic of the underlying mechanism of protecting gut barrier. Reproduced with permission from Ref. [209]. Copyright 2020, Springer. D The fluorescence intensity of FITC-CS microspheres in different residence time of different time (Left→Right:Stomach, Duodenum, Jejunum and Colon) varied from 2 to 36 h. Reproduced with permission from Ref. [210]. Copyright 2016, Elsevier.