Fig. 4

In vitro cell cytotoxicity and recruitment effect of Exos@SFMA on bone marrow stromal cells (BMSCs) and in vitro immunosuppressive effect of Exos@SFMA on Tfh cell polarization. (a) Live/dead assay of BMSCs cultured on hydrogels for 3 days. Scale bar: 100 μm. (b, c) Migration of BMSCs toward Exos@SFMA. (C: Area where BMSCs were seeded; H: Area where hydrogels were fabricated; Arrow: Direction of BMSCs migration) scale bar: 200 μm. Values represent means ± S.D. (n = 3). (d) Cell viability of L929 cells cultured on hydrogels. Values represent means ± S.D. (n = 3). (e) Schematic illustration of the transwell assay and the accumulation of PKH67-labeled OE-MSC-Exos (green) released by Exos@SFMA hydrogel in T cells after 24, 48, 72 h of incubation. (bar = 10 μm). (f) Relative green fluorescence intensity of T cells after 24, 48, 96 h of incubation. Values represent means ± S.D. (n = 4). (g) The proportions of Tfh cells cultured on Exos@SFMA hydrogel after 72 h. Values represent means ± S.D. (n = 3). *P < 0.05, **P < 0.01, ***P < 0.001