Hybrid scaffolds of gelatin-siloxane releasing stromal derived factor-1 effective for cell recruitment

Scaffolds with the capacity to deliver signaling molecules are attractive for bone regeneration. Here, we developed bioactive siloxane-gelatin hybrid scaffolds via a sol gel process containing stromal derived factor-1 (SDF-1) to recruit osteoprogenitor/stem cells. The process was undertaken under room temperature aqueous conditions, which enabled therapeutic molecules to be effectively incorporated. After the sol-gel reaction and lyophilization process, well-crosslinked hybrid scaffolds were obtained with porosities of 80-90%. Dynamic mechanical analysis of the hybrid scaffolds showed significant improvement in storage modulus values (from 10 to 110 kPa) with increasing siloxane content. The protein release capacity of the scaffolds was investigated using a model protein cytochrome C (cyto C). The cyto C safely loaded onto the scaffolds exhibited, except the initial burst of 30% within a day, highly sustainable release, with approximately 70-80% of the loading amount for up to 4 weeks. Target molecule SDF-1 was loaded and released from the scaffolds, and the effects on the homing of mesenchymal stem cell were studied. Results demonstrated significant enhancement in the migration of cells to the SDF-1 loaded scaffolds. Taken together, the developed hybrid scaffolds are considered to be useful in loading and delivering signaling molecules such as SDF-1 to recruit osteoprogenitor /mesenchymal stem cells in the bone regeneration process.