A Mechanically Robust PVA-xylosylated Sericin Composite Hydrogel Membrane with Enhanced Biocompatibility by Unidirectional Dehydration Throught Nanopore

The high molecular weight sericin recovered by using degumming method of high-temperature and high-pressure water was subjected to a Maillard reaction (MR) with xylose, and the resulting xylosylated sericin (XS) has good water solubility. A mechanically robust, soft, and transparent PVA hydrogel composite membrane (PVA-XS) was obtained by mixing XS (20 w%) into an aqueous PVA solution based on unidirectional nanopore dehydration (UND). The mechanical strength, elongation, and elastic modulus of PVA-XS reached 1.68 MPa, 519.83%, and 0.27 MPa, respectively. UND at 85 °C yielded a hydrogel composite membrane with stronger mechanical properties; these values were 9.94 MPa, 627.20%, and 1.49 MPa. These composite hydrogels have 3D porous structures with pore sizes ranging from 2 to 20 μm, and there was no phase separation. Murine L-929 cells adhered, grew, and proliferated normally on the scaffold. The digestion rates of PVA-XS in both trypsin and alkaline protease were faster than that of high temperature-annealed cast PVA-XS (acPVA-XS). Implantation in vivo did not induce an obvious tissue immune response. The mechanical properties and enzymatic degradation rate of PVA-XS were controlled by UND temperature and XS incorporation. Therefore, the UND-based composite hydrogel has potential applications in the implantation, repair, and regeneration of biological tissues.