Design of novel poly(L-lactide)-based shape memory multiblock copolymers for biodegradable esophageal stent application

Abstract

Esophageal cancer is a globally prevalent malignancy known for its extremely aggressive nature and high fatality rates. However, the conventional stents used in its treatment pose limitations including rigidity, non-degradability, and a lack of anti-inflammatory action. Shape memory multiblock copolymer stents (SMBS) have attracted considerable attention because of their distinctive characteristics. Nonetheless, achieving a variety of key functionalities, such as biocompatibility, biodegradability, thermoresponsiveness (body temperature, 37 °C), water responsiveness (biofluid), flexibility, and robustness, in a simple polymer system for practical applications still presents a significant problem. Herein, a versatile SMBS that is capable of delivering all the aforementioned key functionalities is proposed. This SMBS can efficiently be prepared via a rapid two-step strategy, leveraging the shape memory effect (SME) of a poly(L-lactide) (PLA)-based physical crosslinking network programmed into specific shapes. The proposed stent design incorporates bio-based PLA with flexible and hydrophilic polyethylene glycol (PEG), resulting in PEG-PLA multiblock copolymers with tunable transition temperatures (31.90–54.60 °C), effectively covering the body temperature (37 °C). Additionally, PEG-PLA exhibited a wide range of water uptake ratio of 41 % to 328 % and satisfactory elongation at break (142.8 % to 1920.6 %), and desired pH-dependent and simulated gastrointestinal biodegradability. Specifically, PEG₄₀₀₀PLA₁₅₀₀ displayed excellent body temperature-triggered (with a recovery rate of 99.5 %) and water-triggered dual SME, which allowed it to potentially be fabricated into on-demand synchronous shape memory and drug-release functional SMBS for esophageal stenosis therapy. The results of this study indicate that the proposed SMBS holds substantial potential for biomedical applications.