Adhesive Nanoparticle‐in‐Microgel System with ROS Scavenging Capability and Hemostatic Activity for Postoperative Adhesion Prevention

Abstract Postoperative adhesion is a noteworthy clinical complication in abdominal surgery due to the existing physical barriers are unsatisfactory and inefficient in preventing its occurrence. In this work, an elaborate nanoparticle‐in‐microgel system ( nM Gel) is presented for postoperative adhesion prevention. nMG el is facilely formed by crosslinking manganese dioxide (MnO 2 ) nanoparticles‐loaded gelatin microspheres with polydopamine using a modified emulsification‐chemical crosslinking method, generating a nano‐micron spherical hydrogel. After drying, powdery nM Gel with sprayability can perfectly cover irregular wounds and maintains robust tissue adhesiveness even in a wet environment. Additionally, nM Gel possesses prominent antioxidant and free radical scavenging activity, which protects cell viability and preserves cell biological functions in an oxidative microenvironment. Furthermore, nM Gel displays superior hemostatic property as demonstrated in mouse tail amputation models and liver trauma models. Importantly, nM Gel can be conveniently administrated in a mouse cecal defect model to prevent adhesion between the injured cecum and the peritoneum by reducing inflammation, oxidative stress, collagen synthesis, and angiogenesis. Thus, the bioactive nM Gel offers a practical and efficient approach for ameliorating postsurgical adhesion.