Double-hydrophilic block copolymers (DHBCs), consisting of at least two different water-soluble blocks, are an alternative to the classical amphiphilic block copolymers and have gained increasing attention in the field of biomedical applications. Although the chemical nature of the two blocks can be diverse, most classical DHBCs consist of a bioeliminable non-ionic block to promote solubilization in water, like poly(ethylene glycol), and a second block that is more generally a pH-responsive block capable of interacting with another ionic polymer or substrate. This second block is generally non-degradable and the presence of side chain functional groups raises the question of its fate and toxicity, which is a limitation in the frame of biomedical applications. In this review, following a first part dedicated to recent examples of non-degradable DHBCs, we focus on the DHBCs that combine a biocompatible and bioeliminable non-ionic block with a degradable functional block including polysaccharides, polypeptides, polyesters and other miscellaneous polymers. Their use to design efficient drug delivery systems for various biomedical applications through stimuli-dependent self-assembly is discussed along with the current challenges and future perspectives for this class of copolymers.

由至少两种不同的水溶性嵌段组成的双亲水嵌段共聚物（DHBC）是经典两亲嵌段共聚物的替代品，并且在生物医学应用领域中越来越受到关注。尽管两个嵌段的化学性质可能不同，但大多数经典的DHBC包括可生物消除的非离子嵌段（如聚乙二醇），以促进在水中的溶解，而第二个嵌段通常是能够响应pH值的嵌段与另一种离子聚合物或底物相互作用的过程。第二个嵌段通常是不可降解的，并且侧链官能团的存在提出了其命运和毒性的问题，这是生物医学应用框架中的限制。在这篇评论中 在第一部分专门介绍不可降解的DHBC的最新实例之后，我们将重点介绍将生物相容性和可生物消除的非离子嵌段与可降解的功能嵌段（包括多糖，多肽，聚酯和其他杂类聚合物）相结合的DHBC。讨论了它们如何通过依赖于刺激的自组装为各种生物医学应用设计有效的药物输送系统，以及此类共聚物的当前挑战和未来前景。