Shape transformation of polymer particles is generally a nonequilibrium dynamics process. Controlling the shape transformation of polymers is increasingly attractive and challenging for scientists due to their extensive use in drug delivery and cancer therapy. Herein, we investigated the UV-triggered shape transformation pathway of polymeric vesicles assembled from Polystyrene-block-poly(4-vinylpyridine) and 4-hydroxyazobenzene (PS-b-P4VP(Azo–OH)) and the direct assembly pathway of UV-irradiated PS-b-P4VP(Azo–OH) homogeneous solution. In the shape transformation process, well-assembled vesicles can be transformed into toroid, cylindrical, rod-like, and spherical micelles. In the direct assembly pathway, rod-like and spherical micelles can be obtained. Interestingly, the toroid micelles can be obtained only from the UV-triggered shape transformation pathway. Contrasting the two pathways reveals the pathway dependence of PS-b-P4VP(Azo–OH) assembly, suggesting that the final assembly morphology is determined by the initial state and dynamic process. The speed of UV-triggered shape transformation and the final morphology of assemblies can be tuned easily by adjusting the UV illuminance, time, and content of Azo–OH addition. Moreover, the light-responsive polymeric vesicles can be used as drug carriers and have the potential to release drugs precisely.
The left atrial appendage (LAA) occluder is an important medical device for closing the LAA and preventing stroke. The device-related thrombus (DRT) prevents the implantation of the occluder in exerting the desired therapeutic effect, which is primarily caused by the delayed endothelialization of the occluder. Functional coatings are an effective strategy for accelerating the endothelialization of occluders. However, the occluder surface area is particularly large and structurally complex, and the device is subjected to a large shear friction in the sheath during implantation, which poses a significant challenge to the coating. Herein, a hydrogel coating by the in situ UV-triggered polymerization of double-network polyelectrolytes is reported. The findings reveal that the double network and electrostatic interactions between the networks resulted in excellent mechanical properties of the hydrogel coating. The sulfonate and Arg-Gly-Asp (RGD) groups in the coating promoted hemocompatibility and endothelial growth of the occluder, respectively. The coating significantly accelerated the endothelialization of the LAA occluder in a canine model is further demonstrated. This study has potential clinical benefits in reducing both the incidence of DRT and the postoperative anticoagulant course for LAA closure.
危险品化学品经营许可证（带存储）