Development of silica grafted poly(1,8-octanediol-co-citrates) hybrid elastomers with highly tunable mechanical properties and biocompatibility

Biodegradable elastomers are attractive in soft tissue regeneration due to their biomimetic viscoelastic properties and biocompatibility. However, conventional elastomers are inherently weak and lack the bioactivity required for highly efficient tissue regeneration. Silica-based biomaterials have shown high mechanical stiffness and special bioactivities including stimulating osteogenesis and angiogenesis by enhancing corresponding gene expressions. Here, by a facile polymerization, we synthesized a series of silica grafted poly (1,8-octanediol-co-citrate) (SPOC) hybrid elastomers with highly tunable physicochemical properties and bioactivities. The silica phase was successfully grafted to the side chain of POC. The silica phase incorporation significantly endowed POC elastomers with highly controlled thermal stability, mechanical properties, hydrophilicity, biodegradation and biocompatibility. The tensile strength, initial modulus and elongation of SPOC hybrid elastomers were highly tunable and range from 2-15 MPa, 4-25 MPa and 50-140% respectively, which is almost a four-fold enhancement compared with pure POC elastomers. In addition, SPOC elastomers significantly enhanced the proliferation and metabolic activities of multiple cell lines including the adipose-derived stem cells, fibroblasts, myoblasts and osteoblasts, indicating their high biocompatibility. These optimized structures and properties of the silica-grafted hybrid elastomers make them promising for soft and hard tissue regeneration applications.