A Geometrically Tunable Cardiovascular Shunt for the Individualized Care of Neonates with Congenital Heart Defects.

Congenital heart defects (CHDs), particularly single-ventricle anomalies such as hypoplastic left heart syndrome (HLHS), require early surgical intervention using fixed-diameter vascular shunts. However, current shunts are incapable of adapting to the physiological changes of infant growth, often leading to hemodynamic imbalance and elevated mortality risk. Here, we report a geometrically tunable cardiovascular shunt lined with a photoresponsive hydrogel based on methacrylated dextran (DexMA) and dithiothreitol (DTT). This dual-stage crosslinked hydrogel system enables minimally invasive modulation of the inner lumen diameter in response to external blue light. We optimized the hydrogel composition to achieve both mechanical robustness (Young's modulus ≈ 8.5 kPa) and light-induced deswelling, allowing for lumen expansion up to 39% with high stability over one month. In vitro studies confirmed excellent cytocompatibility, hemocompatibility, and minimal immune activation. Prototype annular shunts demonstrated precise, programmable diameter increases (15-18%) corresponding to computational models of infant growth. This dynamic, photoresponsive platform is a critical advance toward implantable materials for personalized cardiovascular interventions and a significant step toward growth-accommodating pediatric medical devices.