Thiol-ene-mediated Degradable POSS-PEG/PEG Hybrid Hydrogels As Potential Cell Scaffolds in Tissue Engineering

Tissue engineering provides therapeutic strategies for the loss or failure of human organs and tissues. As a threedimensional biomaterial that simulates extracellular matrix (ECM) in tissue engineering, hydrogels have attracted much attention and been used as cell scaffolds. Herein, three POSS-PEG/PEG hydrogels with different solid contents were designed and developed through thiol-ene click reaction between a star-shaped cross-linker allyl-terminated poly(ethylene glycol)-functionalized polyhedral oligosiloxane (POSS-PEG-Allyl) and poly (ethylene glycol)-dithiol (SH-PEG-SH). The chemical structures, microscopic morphologies, element distribution mapping, rheological properties, swelling properties, in vitro degradation and cytocompatibility of the hydrogels were further investigated. The results showed that the hybrid hydrogels contain a large amount of water, which can create a suitable water environment for cell growth. The mechanical strength of the hybrid hydrogels is improved by introducing POSS nanoparticles to the hydrogel system, and the ester groups in the cross-linker allow the hydrogel network can be biodegrade by hydrolytic cleavage. The mechanical strength and the degradation rate can be adjusted by the solid content of the hybrid hydrogels. Besides, the hybrid hydrogel has excellent cell compatibility and porous internal structure, which provide conditions for cell growth and proliferation. Therefore, it can be considered that the hybrid hydrogel has great application potential as a cell scaffold material.