A Novel Enzyme-Mediated Controllably Constructed Hydrogel Based on PDI

Protein disulfide isomerase (PDI) mainly exists in the endoplasmic reticulum and plays a crucial role in the correct folding of proteins. PDI catalysis can precisely regulate the breaking and formation of disulfide bonds. This paper designed a double network hydrogel based on the PDI enzyme. The cystamine (CBA) with disulfide bonds in the middle and double bonds at both ends were introduced in the dense network of hydrogels. The results show that the molar concentration of CBA significantly influences the mechanical properties of hydrogels. The CBA is a dense cross-linker in double network (DN) hydrogel, the higher the molar concentration of CBA, the higher the density of the cross-linker, and the higher the Young's modulus of DN hydrogels. When the CBA is 100 mM, the hydrogels have the highest toughness. The presence of PDI enzyme also has an important influence on the mechanical properties of DN hydrogels. The disulfide bonds in DN hydrogels can be broken when the force-coupled enzymatic reactions, thereby Young's modulus of the hydrogels can be changed. The research results may provide a new method for the construction of biomaterials.