Controlled Hydrogel Surfaces Adhesion via Macrophase Separation Polymerization Triggered by Electrostatic Interaction for Wound Dressing and Bio‐Sensor

Abstract Asymmetrical hydrogels with selective tissue adhesion represent a significant advancement in biomaterials for preventing postoperative adhesion and restoring internal tissues. In this work, a one‐step macrophase separation polymerization method triggered by electrostatic interactions is developed to fabricate asymmetrical hydrogels (denoted as QAD). Inspired by barnacle cement proteins, phenylboronic acid is incorporated into the top surface of the hydrogel for strong wet tissue adhesion. Meanwhile, quaternary ammonium chitosan (QCS) functionalized with zwitterions and acrylic acids formed bulky monomers, which then underwent macrophase separation polymerization and sank down to achieve the bottom surface with non‐adhesion. Such hydrogels not only effectively mitigated the challenges of postoperative adhesion, but also exhibited excellent hemostatic properties, thereby reducing the bleeding from 243 mg (gauze) to 16.9 mg. Over a period of 14 days, these hydrogels achieved a remarkably enhanced repair rate of 96.7%, as opposed to 85.6% in the control group. Moreover, an abundant quantity of free ions within the QAD hydrogel endowed it with the capacity to record pulse signal waveforms and convert throat sounds into electrical signals. In summary, this research presents a novel approach to asymmetrical hydrogels, offering promising solutions for adhesion prevention, wound management, and clinical monitoring.