Passivated hydrogel interface: Armor against foreign body response and inflammation in small-diameter vascular grafts

The development of small-diameter vascular grafts (SDVGs) still faces significant challenges, particularly in overcoming blockages within vessels. A key issue is the foreign-body response (FBR) triggered by the implants, which impairs the integration between grafts and native vessels. In this study, we applied an interfacial infiltration strategy to create a stable, hydrophilic, and passivated hydrogel coating on SDVGs. This coating effectively resisted FBR and improved integration between the grafts and host tissue. We also incorporated anthocyanins, an antioxidant, into the hydrogel network to mitigate oxidative stress and promote endothelialization. The hydrogel coating exhibited excellent stability, retaining its integrity during continuous flushing over 15 days. Anthocyanins were released in response to reactive oxygen species (ROS), reducing inflammation and enhancing vascularization in a mouse subcutaneous implantation model. In a rabbit carotid artery replacement model, the SDVGs exhibited rapid endothelialization, guided vascular remodeling, and inhibited calcification, showing strong potential for clinical application. This study presents a straightforward and effective approach to improve the patency rate, endothelialization, and anti-calcification properties of SDVGs by equipping them with a protective anti-FBR and anti-inflammation hydrogel layer.