Fig.1

Characterization of MSNs-Bi. a The upper panel shows the schematic diagram of MSNs-Bi; the lower panel shows the SEM micrographs of naked Bifidobacterium (left) and Bifidobacterium with MSNs attached on their surface (right), scale bars = 500 nm. b Confocal images of MSNs-Bi synthesized by FITC-labeled Bifidobacterium and Cy3-labeled MSNs; FITC (green), Cy3 (Red), scale bars = 5 µm. c Zeta potential of Bifidobacterium and MSNs. d Relative fluorescence intensity of Cy3-MSNs-Bi for monitoring the changes of MSNs on the surface of Bifidobacterium in Krebs–Henseleit solution. e Viability of Bifidobacterium in MSNs-Bi during exposure to Krebs–Henseleit solution