A Biodegradable Janus Sponge for Negative Pressure Wound Therapy

Negative pressure wound therapy (NPWT) is effective in repairing serious skin injury. The dressing used in the NPWT is important for wound healing. In this paper, we develop biodegradable amphiphilic polyurethanes (PUs) and fabricate the PUs into sponges as wound dressings (Bi_@e) with Janus pore architectures for NPWT. The Bi_@e is adaptive to all the stages of the wound healing process. The Janus Bi_@e sponge consists of two layers: the dense hydrophobic upper layer with small pores provides protection and support during negative pressure drainage, and the loose hydrophilic lower layer with large pores absorbs large amounts of wound exudate and maintains a moist environment. Additionally, antibacterial agent silver sulfadiazine (SSD) is loaded into the sponge against Escherichia coli and Staphylococcus aureus with a concentration of 0.50 wt%. The Janus sponge exhibits a super absorbent capacity of 19.53 times its own water weight and remarkable resistance to compression. In a rat skin defect model, the Janus Bi_@e sponge not only prevents the conglutination between regenerative skin and dressing but also accelerates wound healing compared to commercially available NPWT dressing. The Janus Bi_@e sponge is a promising dressing for the NPWT.