Nonmulberry silk protein sericin blend hydrogels for skin tissue regeneration - in vitro and in vivo

The damage to the skin is most prominent and evident as it is our first line of defense and unremittingly under attack by biological and environmental factors. The restoration of the skin is dependent on the extent of the injury. To explore the prospects of new biomimetic material, bi-layered skin construct is fabricated in vitro with nonmulberry silk protein sericin and chitosan hydrogels using human dermal fibroblasts and keratinocytes. The in vitro analysis of the hydrogels showed enhanced adhesion, proliferation, and migration of skin cells with coordinated interaction amongst themselves leading to the synthesis of collagen IV and matrix metalloproteinase (MMP2 and MMP9). The in vivo evaluation indicates the regeneration of skin with densely packed collagen and formation of matured blood vessels in the animals implanted with sericin containing hydrogels. Moreover, the local and systemic immune response determined in vivo exhibits the biosafety of sericin based hydrogels. In addition, the cross-sectional analysis of the implanted hydrogels displays infiltration of the skin tissue cells into the hydrogels marking their biocompatibility and non-toxicity. The cumulative analysis of the in vitro and in vivo observations demonstrates that the sericin based hydrogels are non-inflammatory, supports the regeneration and repair of the skin tissue.