pH-responsive printable conductive hydrogels loaded with ApoVs promote diabetic wound repair through oxidative stress scavenging and macrophage reprogramming

Compared with normal wounds, chronic diabetic wounds involve a more complex pathological microenvironment. Cellular dysfunction, microcirculatory disorders, and high levels of oxidative stress often lead to the progression of diabetic wounds to chronic, refractory ulcers. The management of chronic diabetic wound healing remains a clinical priority and a challenging problem. Traditional wound dressings provide a physical barrier to isolate the wound from foreign substances while creating gaps that block endogenous electrical conduction. We incorporated conductive materials-PEDOT:PSS, polypyrrole (PPy), and Ti₃C₂T_x (MXene)-into a boron-crosslinked polyvinyl alcohol (PVA) dynamic network. MXene, a nanozyme, possesses remarkable ROS-scavenging ability and can effectively mitigate ROS accumulation. Dynamic crosslinking of the hydrogel via borate bonds endows it with self-healing and pH-responsive capabilities. By adjusting the ratio of hydrogel components, we optimized its processability, enabling the construction of various simple/complex 3D models via DIW 3D printing. Furthermore, we enhanced the antibacterial properties of the hydrogel by introducing additional boron ions, thereby mitigating persistent inflammatory responses caused by bacterial infections. Apoptotic vesicles released during mesenchymal stem apoptosis contain diverse bioactive substances-including proteins and RNA-that play critical roles in tissue repair. Through in vitro cellular experiments, we demonstrated the beneficial effects of umbilical cord stem cell-derived apoptotic vesicles on cell proliferation, migration, and angiogenesis. Conductive hydrogels were utilized as smart carriers to deliver apoptotic vesicles to the injury site. In summary, the delivery system based on PPMP-conductive hydrogels/apoptotic bodies (ApoVs) exhibits excellent wound healing capabilities and processability and offers a promising approach to chronic wound management.