4D Printing of Overall Radiopaque Customized Bionic Occlusion Devices.

Percutaneous closure of ventricular septal defect (VSD) can effectively occlude abnormal blood flow between ventricles. However, commonly used Nitinol occlusion devices have non-negligible limitations, such as nondegradability leading to life-threatening embolization; limited device size predisposing to displacement and wear; only a few radiopaque markers resulting in inaccurate positioning. Nevertheless, the exploration of customized, biodegradable, and overall radiopaque occluders is still vacant. Here, overall radiopaque, biodegradable, and dynamic reconfigurable 4D printed VSD occluders are developed. Based on wavy bionic structures, various VSD occluders are designed and manufactured to adapt to the position diversity of VSD. The customized configuration, biocompatibility, and biodegradability of the developed 4D printed bionic occluders can eliminate the series of complications caused by traditional occluders. The overall radiopacity of 4D printed VSD occluders is validated ex vivo and in vivo, whereby accurate positioning can be assured. Notably, the preparation strategies for 4D printed occluders are scalable, eliminating the barriers to mass production, and marking a meaningful step in bridging the gap between modeling and clinical application of 4D printed occlusion devices. This work opens attractive perspectives for the rapid manufacturing of customized intelligent medical devices for which overall radiopacity, dynamic reconfigurability, biocompatibility, and biodegradability are sought.