FeS2 nanozymes@halloysite clay nanotube/polyvinyl alcohol/sodium alginate composite hydrogel for hemostasis and bacterial-infected wound healing.

Acute skin injuries and chronic non-healing wounds are knotty problems in daily life. Due to the damaged skin barrier at the wound site, external bacteria can easily invade the wound and cause infection. To address the issue, polyvinyl alcohol/sodium alginate/FeS2 nanozyme@halloysite (PS-FeH) composite hydrogel was designed in this study, which can effectively stop bleeding, inhibit bacterial infection, and promote wound healing. Halloysite nanotubes (HNTs) are a nano-clay mineral material with natural procoagulant activity and can be used as an active ingredient to control bleeding. The anchoring of FeS2 nanoparticles (with diameter of ∼5.12 nm) on HNTs surface enhances the coagulation ability, and more importantly, the nanozymes activity of FeS2 is significantly enhanced due to decreased size brought by the confinement effect of HNTs. FeS2@HNTs exhibits significant antibacterial properties with antibacterial efficiency of 99.9 % under acidic conditions, which is related to its peroxidase (POD) activity. In addition, the FeS2@HNTs can mimic superoxide dismutase (SOD) and catalase (CAT) in neutral conditions, providing it the ability to scavenge reactive oxygen species (ROS). The FeS2@HNTs was introduced to polyvinyl alcohol/sodium alginate composite hydrogel which is cross-linked by dynamic borate bonds and shows good tissue adhesion, self-healing and biocompatibility. When irradiated with near-infrared light, the PS-FeH composite hydrogel can fully exert its maximum enzyme activity. The hemostatic properties, multiple enzyme-like activities and excellent photothermal properties of FeS2@HNTs nanozymes endow PS-FeH hydrogel with powerful antibacterial and anti-inflammatory properties, thereby enhancing blood coagulation property with hemostasis time of ∼96 s and wound healing in vivo. Therefore, the prepared PS-FeH hydrogel combines the advantages of nanozymes and hydrogel, which provides a promising therapeutic platform for rapid hemorrhage control and effective treatment of bacterially infected wounds.