Antioxidant and anti-inflammatory activities of Prussian blue nanozyme promotes full-thickness skin wound healing

Excessive reactive oxygen species (ROS) and unresolved inflammations are the major causes of impaired wound healing as they overwhelm the cellular antioxidant system and impede the healing process. In this study, we examined the application of Prussian blue (PB) nanozyme as a novel material for cutaneous wound healing through the alleviation of excessive ROS and inflammation modulation. The PB nanoparticles not only exhibited hydrogen peroxide (H2O2) degradation activity but also showed strong superoxide scavenging ability. PB nanozyme mitigated the intracellular ROS at a high oxidative stress environment, resulting in a pronounced cytoprotective effect. Moreover, PB nanozyme also displayed significant anti-inflammatory activity, as evident from the suppression of inflammatory mediators in the lipopolysaccharide (LPS) induced macrophage cells. Encouraged by the in vitro results, we evaluated the in vivo therapeutic efficacy of PB nanozyme in a full-thickness cutaneous wound model combined with LPS treatment to mimic bacterial infection. The beneficial effects of topically applied PB nanozyme on wound healing and tissue regeneration were evident compared to the control. The periodical administration of a low amount (50 μg × 4) of PB nanoparticles exhibited faster wound closure as well as collagen deposition, maturation, and organization. Moreover, the PB treatment effectively induced the differentiation of keratinocytes, enhanced the neovascularization, and reduced macrophage burden in the entire wound site. Thus, PB nanozyme not only accelerated the healing process in an infection-mimicking cutaneous wound model but also exhibited tissue regeneration characteristics owing to the synergistic effect of ROS-scavenging and anti-inflammatory activities.