Silk/chitosan biohybrid hydrogels and scaffolds via green technology

Silk fibroin protein-based hydrogels and 3D scaffolds in combinations with chitosan were designed with a focus on green technology. The physico-chemical properties were modulated using ultrasonication processing to avoid the use of organic solvents or chemical crosslinking. The ultrasonication of mixtures of silk and chitosan induced a conformational change of the silk from random coil to beta-sheet resulting in the self-assembly of the hydrophobic peptide segments in the protein, entrapping chitosan chains in these silk networks. These biohybrid materials were prepared with different physico-chemical properties by varying the relative concentrations of silk and chitosan. In combination with lyophilization, interconnected porous 3D scaffolds with controlled morphologies were generated. MC3T3-E1 cells were successfully encapsulated in silk fibroin protein and silk fibroin protein-chitosan hydrogels and colonized the scaffolds. These engineered biohybrid hydrogel and scaffold network systems can be utilized to encapsulate bioactive molecules, thus providing a versatile set of biomaterials with retention of degradability, but without the use of organic solvents or chemical crosslinking during preparation.