Nano-hydroxyapatite doped tyramine gelatin/silk fibroin scaffold for the regeneration of cancellous bone defects

Gelatin (G) and silk fibroin (SF) are well-established as scaffold materials for bone regeneration; however, their limited binding abilities and mechanical properties often result in less-than-ideal outcomes. In this study, we sought to enhance the stability of a silk fibroin/gelatin biomimetic scaffold by introducing a tyramine bond to the gelatin and incorporating nanohydroxyapatite as a bioactive element. This innovation led to the development of a more robust silk fibroin/nano-hydroxyapatite/gelatin tyramine biomimetic scaffold (SHGT). The biomimetic scaffold was fabricated through an enzymatic reaction catalyzed by horseradish peroxidase/hydrogen peroxide (HRP/H₂O₂), which facilitated the interaction between a high concentration of silk fibroin (17%) and gelatin tyramine (GT). Additionally, nano-hydroxyapatite (nHA) was incorporated as a bioactive filler to promote bone repair. Our findings indicated that the SHG biomimetic scaffold, initially designed as a sponge, was transformed into an SHGT scaffold with improved brittle fracture resistance, thus broadening its potential applications in bone reconstruction. Moreover, the data showed that combining GT with RGD sequences and HA as a bioactive component significantly enhanced the viability of bone marrow stromal cells (BMSCs) cultured on the scaffold. This synergistic effect highlights the potential of the SHGT scaffold as a promising material for bone tissue engineering.