Biodegradable polymer nanoparticles are an important class of materials used in several applications for their unique characteristics. In particular, the ones stabilized by zwitterionic materials are gaining increased interest in medicine as alternative to the more common ones based on poly(ethylene glycol) thanks to their superior stability and ability to avoid both the accelerated blood clearance and allergic reactions. In this work, a novel class of zwitterionic based NPs has been produced, and a method to independently control the nanoparticle size, degradation time, and polymer molecular weight has been developed and demonstrated. This has been possible by the synthesis and the fine-tuning of zwitterionic amphiphilic block copolymers obtained via the combination of ring-opening polymerization and reversible addition–fragmentation chain transfer polymerization. The final results showed that when two block copolymers contain the same number of caprolactone units, the one with longer oligoester lateral chains degrades faster. This phenomenon is in sharp contrast with the one seen so far for the common linear polyester systems where longer chains result in longer degradation times, and it can be used to better tailor the degradation behavior of the nanoparticles.

中文翻译：

---

基于两性离子聚酯的纳米粒子，具有可调的尺寸，聚合物分子量和降解时间

可生物降解的聚合物纳米粒子因其独特的特性而在多种应用中是一类重要的材料。尤其是，两性离子材料稳定的那些由于其优越的稳定性和避免加速血液清除和过敏反应的能力，逐渐取代了基于聚乙二醇的更常见药物，从而在医学上引起了越来越多的兴趣。在这项工作中，已经产生了一类新型的基于两性离子的NP，并且已经开发并证明了一种独立控制纳米颗粒尺寸，降解时间和聚合物分子量的方法。通过开环聚合和可逆加成-断裂链转移聚合相结合获得的两性离子两亲嵌段共聚物的合成和微调，这是可能的。最终结果表明，当两种嵌段共聚物包含相同数量的己内酯单元时，具有更长的低聚酯侧链的单体降解得更快。该现象与迄今为止常见的线性聚酯体系的现象形成鲜明对比，在普通线性聚酯体系中，较长的链会导致更长的降解时间，并且可以用来更好地调整纳米粒子的降解行为。