Design of 4D printed shape-changing tracheal stent and remote controlling actuation

has a good application prospect.The biodegradable stent can effectively reduce the damage to patients and improve the therapeutic performance of stents.In this work,a series of shape memory polylactic acid(Fe_(3)O_(4))composite tracheal stents were manufactured by 4D printing.The composite tracheal stents with different structures were designed.Moreover,with the addition of magnetic particles Fe3 O4,the shape memory PLA/Fe_(3)O_(4)composite tracheal stent has a magnetic driving effect.Under the magnetic field,the shape recovery process is completed within 40 s,and the shape recovery rate is more than 99%.Moreover,the 4D printed tracheal stent was also triggered by the irradiation of infrared lamp to realize the remote controlling recovery.The research on the structure design and driving method of 4D printing tracheal stent expands the application scope of shape memory polymer composites in biomedical field,provides a new way for personalized implantable medical devices and minimally invasive surgery.It is of great significance for better precision medical treatment.

Programming Shape-Morphing Behavior of Zwitterionic Polymer/Liquid Crystal Composite with Humidity-responsive Self-healing Performance

In this study,a zwitterionic polymer/liquid crystals composite film with programming shape-morphing behavior and humidityresponsive self-healing performance was prepared by blending a zwitterionic polymer and liquid crystalline azobenzene compound in solution,followed by film-forming in a mold without tedious or multistep synthetic route.The as-obtained zwitterionic polymer/liquid crystal composite film exhibited programming shape-morphing behavior under different stimuli.In this process,the temporary shape of the composite film was memorized after the removal of the stimuli.Such characteristics would fit the requirements of intelligence and energy-saving for stimuliresponsive shape-changing materials.Moreover,the composite film showed humidity-responsive self-healing performances under wet conditions at room temperature.In summary,the simple design and preparation route of the zwitterionic polymer/liquid crystal composite film with programming shape-morphing behavior and mild condition-responsive self-healing performance look promising for the fabrication and practical application of novel photo-driven devices and soft robotics.

4D printed shape memory polymers and their structures for biomedical applications

Shape memory polymers are smart materials that produce shape changes under external stimulus conditions.Four-dimensional(4D)printing is a comprehensive technology originate from deformable materials and three-dimensional(3D)printing technology.At present,4D printed shape memory polymers and shape-changing structures have been applied in various fields,especially in the field of biomedical science.4D printing technology has made a breakthrough of personalized customization in the traditional medical field,providing a new direction for the further development of the biomedical field.In this review,the recent research and development of shape memory polymer,3D printing technology,4D printed shape memory polymers and shape-changing structures in biomedical area are present.The examples and applications of 4D printed shape memory polymers and their structures in the area of biomedical are also introduced.Based on 4D printing,stimulated by different conditions,3D printed objects can be fabricated into various biomedical applications such as cell scaffolds,vascular stents,bone scaffolds,tracheal stents and cardiac stents by different 3D printing techniques.Finally,the application prospects,existing technical restriction and future development directions of 4D printed shape memory polymers and their structures in the biomedical field are summarized.