Conductive, adaptive, multifunctional hydrogel combined with electrical stimulation for deep wound repair

To promote wound healing and solve the limitations of current hydrogel wound dressings—that is, they can only cover the surface of deep wounds, leaving a cavity underneath that blocks endogenous and external electrical current conduction—we designed an adaptive conductive hydrogel that spontaneously adapted to the shape of wounds. We prepared this hydrogel by including tannic acid (TA) and human-like collagen (HLC) into polyvinyl alcohol (PVA) and borax hydrogel dynamic crosslinking networks, in which borax functioned as a crosslinker and an ionic conductor. Dynamic crosslinking via borate bonds gave the hydrogel adaptive and self-healing properties. Adding HLC and TA changed both the crosslink density and pH of the hydrogel—and thus adjusted the adaptability of the PVA–borax matrix—and imparted functionalities such as hemostasis, antibacterial, anti-inflammation, cell proliferation, and collagen deposition. We also investigated the potential of this adaptive conductive hydrogel in electrical stimulation (ES) therapy. The adaptive conductive hydrogel perfectly fit the cavity of deep wounds, permitted endogenous and external current conduction, facilitated intercellular signaling as well as current transmission from external electrical stimuli, which promoted cell migration and angiogenesis. The hydrogel dressing / ES treatment strategy facilitated wound healing throughout healing. By day 10, a wound was completely closed, and the subcutaneous tissue (blood vessels and pores) was reconstructed. Hence, the combination of an adaptive conductive hydrogel and ES is a promising strategy for treating deep wounds.