Nanosheets doped collagen‑based composite sponge dressing with integrated negative pressure wound therapy, photothermal, and gas therapies for wound healing

Polyvinyl alcohol (PVA) sponges are widely utilized as wound dressings, yet they face limitations in clinical practice, particularly in addressing bacterial infection. Herein, a multifunctional composite sponge dressing is developed by incorporating collagen (COL) and a graphene oxide (GO)/BNN6 (a nitric oxide (NO) donor) assembly into a PVA matrix. The resulting GO/BNN6/PVA/COL composite sponge exhibits a three-dimensional porous network, high porosity, excellent liquid absorption, and favorable shape retention. Benefiting from these features, the composite sponge demonstrates efficient negative pressure drainage performance in vitro, achieving a drainage flux of 3515.0 mL·s^-1·m^-2 at 16 kPa, indicating its potential applicability for negative pressure wound therapy (NPWT). Moreover, under near-infrared (NIR) irradiation, GO provides significant photothermal conversion, allowing the sponge to serve as a photothermal therapy (PTT) agent. The localized heat simultaneously triggers the controlled release of NO from BNN6, yielding a combined photothermal and NO-mediated antibacterial effect with inhibition rates exceeding 96% against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Notably, in vivo experiments demonstrate that the GO/BNN6/PVA/COL sponge under NIR irradiation effectively suppresses infection, accelerates wound closure, and promotes granulation tissue formation and skin regeneration. This work presents a versatile sponge dressing that combines the key functions required for NPWT, on-demand PTT, and gas-based antibacterial treatment, demonstrating promising potential for advanced wound management.