Molecular Mechanism of Rabbit Hair Keratin Hydrogel Fabricated via Cryoablation

Keratins are highly attractive natural biomaterials for medical applications due to their inherent self‐assembly characteristics and biocompatibility. In this study, the molecular mechanism of rabbit hair keratin (RHK) gelation during cryogelation is investigated and the influence of cryogelation parameters on the gelation of keratin is systematically evaluated. Re‐xidation of free cysteine thiols and formation of hydrogen bond are determined to be the main stabilizing forces in self‐assembly of RHK gel, and ionic bonds are found to affect the uniformity of keratin hydrogels. pH affects the gelation by changing the electrostatic interaction between keratin molecules. Keratin will accumulate when pH is too low, but the stability of keratin hydrogels becomes worse when the pH is too high. With successive freezing–thawing (FT) cycles, the storage modulus of RHK cryogels substantially improved from 240.66 Pa at FT cycle 3 to 2483.3 Pa at FT cycle 9. Maintaining the balance of the interactive force between keratin molecules and between keratin molecules and water molecules is the basis of preparing uniform and stable keratin hydrogels. The effects of chemical reagents and freezing parameters on the formation process and rheological characteristics of rabbit hair keratin hydrogel are evaluated by modifying rabbit hair keratin and changing the preparation conditions. Quantitative analysis of intermolecular forces shows that the molecular mechanism of rabbit hair keratin hydrogel formation is mainly disulfide bond and hydrogen bond, supplemented by hydrophobic and electrostatic action.