Fig.3

Biodistribution of MSNs-Bi after intranasal instillation. a Fluorescence imaging of organs at 5 h after intranasal instillation of MSNs-Bi (tracing FITC-labeled Bifidobacterium). b Representative confocal images of the brain, spinal cord, and abdomen at 5 h after intranasal instillation of MSNs-Bi; DAPI (blue), FITC (green), and Cy3 (Red); scale bar = 200 μm. c Fluorescence imaging of gastrointestinal contents at different time points after oral administration of FITC-labeled Bifidobacterium and intranasal instillation of MSNs-Bi (FITC labeling for Bifidobacterium)