Fig. 1

TP hydrogel properties when loaded with M2-Exos. (A) The two-step synthesis process of TPME hydrogels was illustrated. TP hydrogels were obtained by cross-linking with TA, Py, and Fe³⁺. TPME hydrogel synthesis occurred through the formation of hydrogen bonds between TA polyphenol groups and phosphate groups in the phospholipids of Exos. (B) Spinal cord tissue can adhere to the hydrogels in vitro. (C) SEM image of TPME hydrogel. (D) 3D image of TPME hydrogel with M2-Exos labeled with PKH26. (E) Rheological study of TP with and without Exos. (F) Cyclic voltammograms of TP and TPME hydrogels. (G) Nyquist curves of TP and TPME hydrogels. (H) Daily release curve of Exos with and without TP (n = 3). (I) The cumulative release profile of Exos with or without TP hydrogel over 14 days (n = 3). (J) Confocal microscopy image of the internalization of fluorescently labeled M2-Exos in PC12 cells. Scale bar = 50 μm. Statistical analysis was performed using ANOVA followed by Tukey’s test (*p < 0.05, **p < 0.01, and ***p < 0.001)