PDMSstar–PEG hydrogels prepared via solvent-induced phase separation (SIPS) and their potential utility as tissue engineering scaffolds

Inorganic–organic hydrogels based on methacrylated star polydimethylsiloxane (PDMSstar-MA) and diacrylated poly(ethylene glycol) (PEG-DA) macromers were prepared via solvent-induced phase separation (SIPS). The macromers were combined in a dichloromethane precursor solution and sequentially photopolymerized, dried and hydrated. The chemical and physical properties of the hydrogels were further tailored by varying the number average molecular weight (Mn) of PEG-DA (Mn = 3.4k and 6k g mol−1) as well as the weight percent ratio of PDMSstar-MA (Mn = 7k g mol−1) to PEG-DA from 0:100 to 20:80. Compared to analogous hydrogels fabricated from aqueous precursor solutions, SIPS produced hydrogels with a macroporous morphology, a more even distribution of PDMSstar-MA, increased modulus and enhanced degradation rates. The morphology, swelling ratio, mechanical properties, bioactivity, non-specific protein adhesion, controlled introduction of cell adhesion, and cytocompatibility of the hydrogels were characterized. As a result of their tunable properties, this library of hydrogels is useful to study material-guided cell behavior and ultimate tissue regeneration.