Effects of the proportion of two different cross-linkers on the material and biological properties of enzymatically degradable PEG hydrogels

A series of enzymatically degradable PEG hydrogels with tunable degradability were prepared by changing the proportions of two cross-linkers, enzymatically degradable cross-linker matrix metalloproteinase (MMP) degradable peptide and non-degradable cross-linker PEG-dithiol, and the effects of the proportion of two cross-linkers on the other properties of PEG hydrogels were also investigated. As the content of the degradable cross-linker increased, their mechanical properties decreased, but their swelling rate gradually increased. LIVE/DEAD cell staining and CCK-8 assay indicated that PEG hydrogels have high biocompatibility and low cytotoxicity, and as the content of the degradable cross-linker increased, the proliferation of cells is more favorable. Furthermore, adipogenic differentiation and osteogenic differentiation assays showed that BMSCs 3D-capsulated in PEG hydrogels can proliferate and then differentiate into osteoblasts or adipocytes, and as the content of degradable cross-linker increased, calcium nodules and the number of fat cells increased. These results demonstrate that the proportions of two cross-linkers have an effect on the physical, chemical and biological properties of PEG hydrogels, and these PEG hydrogels could be used as tissue engineering scaffold materials. •A series of PEG hydrogels with tunable degradability were prepared by changing the proportions of two cross-linkers.•The proportions of two cross-linkers have an effect on the physical, chemical and biological properties of PEG hydrogels.T.•These PEG hydrogels can be used as tissue engineering scaffold materials.