Development of a Multifunctional Platform Based on Strong, Intrinsically Photoluminescent and Antimicrobial Silica-Poly(citrates)-Based Hybrid Biodegradable Elastomers for Bone Regeneration

Biodegradable biomaterials with intrinsically multifunctional properties such as high strength, photoluminescent ability (bioimaging monitoring), and antimicrobial activity (anti-infection), as well as high osteoblastic differentiation ability, play a critical role in successful bone tissue regeneration. However, fabricating a biomaterial containing all these functions is still a challenge. Here, urethane cross-linked intrinsically multifunctional silica-poly(citrate) (CMSPC)-based hybrid elastomers are developed by first one-step polymerization and further chemical crosslinked using isocyanate. CMSPC hybrid elastomers demonstrate a high modulus of 976 +/- 15 MPa, which is superior compared with most conventional poly(citrate)-based elastomers. Hybrid elastomers show strong and stable intrinsic photoluminescent ability (emission 400-600 nm) due to the incorporation of silica phase. All elastomers exhibit high inherent antibacterial properties against Staphylococcus aureus. In addition, CMSPC hybrid elastomers significantly enhance the proliferation and metabolic activity of osteoblasts (MC3T3-E1). CMSPC hybrid elastomers significantly promote the osteogenic differentiation of MC3T3-E1 by improving alkaline phosphatase activity and calcium biomineralization deposits, as well as expressions of osteoblastic genes. These hybrid elastomers also show a minimal inflammatory response indicated by subcutaneous transplantation in vivo. These optimized structure and multifunctional properties make this hybrid elastomer highly promising for bone tissue regeneration and antiinfection and bioimaging applications.