Abstract: Objective To prepare a thymopentin-contained supramolecular hydrogel, and characterize its micromorphology and mechanical property, and further investigate its effects on the cellular uptake and the immunomodulatory performance in vitro. Methods The self-assembling peptide containing thymopentin was prepared by solid phase synthesis method and identified using LC-MS after being purified by high performance liquid chromatography (HPLC). Supramolecular hydrogel was prepared through a heating-cooling process, and its micromorphology and mechanical property were characterized using transmission electron microscopy (TEM) and rheology. The cellular uptake efficiencies of free thymopentin and thymopentin nanofibers were observed by inverted fluorescence microscope after FITC-labeling. The abilities of free thymopentin and thymopentin nanofibers to stimulate RAW 264.7 cells to secrete tumor necrosis factor (TNF-α) were studied by enzyme-linked immunosorbent assay (ELISA). Results A macroscopic visible supramolecular hydrogel was obtained by a heating-cooling process, composing with long cross-linked nanofibers and possessing good ductility of mechanics. Compared with free thymopentin, thymopentin nanofibers showed much more enhanced cellular uptake, and better immunomodulation property as stimulating the RAW 264.7 cells to produce much higher concentration of TNF-α in vitro. Conclusion After rational structural modification, the cellular uptake and immunomodulatory activity of thymopentin, which formed nanomedicine, were significantly enhanced. This study can provide new methods and guidance for improving the therapeutic effect of thymopentin in clinical application.

Key words: thymopentin, self-assembly, supramolecular hydrogel, nanofibers, immunomodulatory