Platinum nanozymes–engineered hydrogel skin patch for localized oxidative stress management

Herein, we report a platinum nanozymes (PtNZs)–engineered hydrogel skin patch fabricated via vat photopolymerization technique, specifically digital light processing (DLP) 3D printing, followed by post-printing immersion and in situ chemical reduction of Pt precursors within the printed lattice. This post-fabrication strategy enables the incorporation of PtNZs throughout the three-dimensional hydrogel network while preserving architectural integrity, achieving broad spatial distribution of Pt within the matrix, and confining Pt within the matrix to prevent uncontrolled release. The approach enables quick, cost-effective, and customizable manufacturing of lattice structures with oxidative stress–modulation capability relevant to skin-contact material systems. The physicochemical and morphological analyses reveal successful nanozyme integration, whereas enzyme-mimetic activity is demonstrated by the reduction of methylene blue (MB) in the presence of hydrogen peroxide. The PtNZs-doped hydrogel exhibited strong catalytic activity, achieving ∼97% MB degradation within 90 min. Biological evaluation further showed that the hydrogel extracts were cytocompatible toward human dermal fibroblasts, with high cell viability (∼95–96%). In addition, the extracts exhibited antioxidant activity through both intracellular reactive oxygen species (ROS) suppression (p < 0.0001) and direct free-radical scavenging (∼54–57%). The mechanical behavior of the 3D-printed lattices is further investigated in both dry and hydrated situations. Overall, these findings provide a proof-of-concept materials platform that combines nanozyme catalysis and architected hydrogel mechanics, while also demonstrating in vitro cytocompatibility and antioxidant functionality relevant to skin-contact and chronic wound–associated oxidative stress environments.