Safe and effective vectors play an important role in nucleic acid delivery processes. Ring-opening reactions are quite often used to produce biomaterials with various functions and properties. Instead of surface-conjugated hydrophilic polymers such as polyethylene glycol, uniformly-distributed hydroxyl groups within one polycation could improve biocompatibility and benefit nucleic acid delivery performances. Hydroxyl groups with uniform distribution are readily produced by ring-opening of O-heterocyclic units. O-Heterocyclic units include cyclic ester (epoxide), carbonate and lactones. Hydroxyl-rich polycationic systems are prepared predominately with aminated poly(glycidyl methacrylate) (PGMA). PGMA is the most common epoxy polymer and can be post-modified readily via epoxide ring-opening reactions by different amine species. Hydroxyl-rich polycationic systems are also reported by ring-opening polymerization between various epoxy and amine units. In addition, post hydroxylation of polycations via different O-heterocyclic ring-opening reactions could give rise to various hydroxyl-rich polycationic systems. More recently, versatile types of hydroxyl-rich polycationic systems with special molecular and topological structures, such as linear, star-shaped, comb-shaped, supramolecular, branched, hierarchical, and hetero-nanostructured carriers, are well studied. This review summarizes recent research activities in hydroxyl-rich polycationic systems. Their different design strategies via O-heterocyclic ring-opening reactions and unique nucleic acid delivery applications are described in detail. The research activities indicate that hydroxyl-rich polycationic systems become versatile and powerful candidates for the development of advanced multifunctional delivery systems of nucleic acids.

安全有效的载体在核酸递送过程中起着重要作用。开环反应通常用于生产具有各种功能和特性的生物材料。代替一个表面共轭的亲水性聚合物（例如聚乙二醇），一个聚阳离子内均匀分布的羟基可以改善生物相容性并有益于核酸传递性能。通过O-杂环单元的开环容易产生具有均匀分布的羟基。O-杂环单元包括环酯（环氧化物），碳酸酯和内酯。富含羟基的聚阳离子体系主要由胺化的聚（甲基丙烯酸缩水甘油酯）（PGMA）制备。PGMA是最常见的环氧聚合物，可以通过不同胺类的环氧化物开环反应轻松地进行后改性。还通过各种环氧和胺单元之间的开环聚合反应，报道了富含羟基的聚阳离子体系。另外，通过不同的O，聚阳离子的后羟基化-杂环开环反应可以产生各种富含羟基的聚阳离子体系。最近，对具有特殊分子和拓扑结构，例如线性，星形，梳状，超分子，支链，分级和杂纳米结构的载体的多种类型的富含羟基的聚阳离子体系进行了很好的研究。这篇综述总结了在富含羟基的聚阳离子体系中的最新研究活动。通过O-杂环开环反应和独特的核酸递送应用，详细描述了它们的不同设计策略。研究活动表明，富含羟基的聚阳离子体系成为开发先进的多功能核酸输送系统的多功能和强大的候选者。