Polyethylene-Glycol-Ornamented Small Intestinal Submucosa Biosponge for Skin Tissue Engineering

Full-thickness skin regeneration is still a clinical challenge for skin defects. Porcine small intestinal submucosa (SIS) has been exploited as a new scaffold for tissue reconstruction due to its excellent biocompatibility and ease of handling and modification. However, the application of SIS is dramatically impeded by its compact structure. Thus, a strategy for improving this property of SIS is highly desirable. Herein, SIS was recross-linked by a four-arm polyethylene glycol (fa-PEG) with succinimidyl glutarate-terminated branches into a three-dimensional (3D) bioactive sponge (SIS-PEG), which possessed porous 3D frameworks to mimic the structure of skin. The addition of a suitable proportion of fa-PEG endowed SIS with a uniform pore size, outstanding bioactivity, and flexible shape to promote a rapid healing of a mouse skin defect. Compared with SIS, the bioactive SIS-PEG sponge exhibited excellent mechanical stability and was less prone to collagenase degradation. Moreover, SIS-PEG provided a minimally invasive way to deliver stem cells for in situ wound repair. Remarkably, in vivo evaluation demonstrated that dissociated epidermal and dermal cells loaded with SIS-PEG could form reconstituted skin with regenerated hair after 21 days of treatment. The SIS-PEG bioactive sponge exhibited great potential for skin tissue engineering.