ZIF-8 Based Active Wound Dressing for pH Modulation and pH-Responsive Delivery of Curcumin and Zn2+: Effect of Acidity on the Drug Release for Antibacterial and Antioxidant Efficacy

Abstract

A wound evolves with variable pHs depending on the healing stage, and the maintenance of mild acidic condition can help healing by deterring the formation of a biofilm. Herein, a dual-layer wound dressing with an acid-responsive zeolitic imidazolate framework-8 (ZIF-8) layer and an acid-modulating layer is designed to control the acid-dependent release of therapeutic agents for the improved healing process. The outer dressing layer is coated with curcumin-incorporated ZIF-8, where curcumin and zinc ions are released upon dissociation of ZIF-8 in an acidic condition. The inner layer, a pH modulator, is fabricated by electrospinning polyvinylpyrrolidone with addition of acetic acid. In vitro release test shows that the outer layer dressing attains a considerably higher release of curcumin and Zn2+ under an acidic condition. Combined with the inner acidic layer, the dual layer dressing exhibits facilitated release of effective agents regardless of environmental pHs, attributed to the proper pH modulation to about 6.5. The anti-oxidant activity of curcumin and antibacterial activity of Zn2+ are confirmed. The study highlights the novel proof-of-concept design of active wound dressing demonstrating the dual functions of pH regulation and the stimulus-responsive drug delivery.