Hydrogen sulfide (H₂S) serves as a key gaseous regulator that not only directs many physiological activities, but also manifests therapeutic benefits to many diseases. Developing H₂S vehicle platforms for its local delivery and long-acting release is important to achieve target gas therapy. Most of the known H₂S-donating polymers contain labile thioester scaffolds within their structures that suffer from the issue of low gas releasing efficiency. Here we present the use of thionoester, a constitutional isomer of thioester, as the functional unit to build a structural platform of cysteine-triggered H₂S donor polymer, polythionoester. Simple exchange of the sulfur and oxygen positions in the carbonyl sulfide scaffold makes the polythionoesters undergo a distinct mechanism of H₂S production, which can largely improve the gas-releasing efficiency (>80%). Moreover, the thionoester-containing block copolymers can self-assemble into vesicles in an aqueous media. We discover that control over the size effect can adjust the vesicle disassembly rate and gas-releasing kinetics. A tunable half-life of H₂S generation (2.6–9.8 h) can be accessed by tailoring the vesicle dimension. This allows such polymersomes to be potential as a gas nanodelivery system for long-lasting gas therapeutics.

中文翻译：

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聚硫酯囊泡：一种用于调节 H2S 释放的高效聚合物平台

硫化氢 (H ₂ S) 是一种关键的气体调节剂，它不仅指导许多生理活动，而且对许多疾病都有治疗作用。开发用于局部释放和长效释放的H _{2 S 载体平台对于实现目标气体治疗非常重要。}大多数已知的 H ₂ S 供体聚合物在其结构中包含不稳定的硫酯支架，这些支架存在气体释放效率低的问题。在这里，我们介绍了使用硫酯（硫酯的一种结构异构体）作为构建半胱氨酸触发的 H _{2结构平台的功能单元}S 供体聚合物，聚硫酯。羰基硫化物支架中硫和氧位置的简单交换使聚硫酯经历了独特的H ₂ S产生机制，这可以大大提高气体释放效率（> 80％）。此外，含硫酯的嵌段共聚物可以在水性介质中自组装成囊泡。我们发现控制尺寸效应可以调节囊泡分解速率和气体释放动力学。通过调整囊泡尺寸可以获得H ₂ S 生成的可调半衰期（2.6–9.8 小时）。这使得这种聚合物囊泡有可能成为用于长效气体治疗的气体纳米输送系统。