Zwitterionic Polymers: Synthesis, Architectures, Properties, and Biomedical Applications

Zwitterionic polymers are a class of polymeric materials characterized by repeating units bearing equal numbers of positively and negatively charged groups. Their unique chemical structure confers a strong hydration effect via ionic solvation, leading to distinctive properties such as resistance to protein adsorption and cell adhesion, effective interfacial lubrication, enhanced drug stability, and antifreezing capability. Consequently, zwitterionic polymers have garnered significant attention in biomedical applications in recent years. This review summarizes zwitterionic polymers through an application-oriented "synthesis-architecture-application" framework. We emphasize that their biomedical performance is not determined solely by types of zwitterionic polymers, but by the hierarchical relationship among synthetic strategy, chain-level topology, material architecture, and application-specific biological interactions. Conversely, application requirements guide the selection of material architecture, polymer topology, synthetic strategy, and zwitterionic polymers. From this perspective, synthetic routes are discussed as tools for controlling polymer topology and architecture, while biomedical applications are analyzed in terms of the material forms and interfacial properties they require. We further discuss the current translational status of zwitterionic polymers, their major clinical challenges, and potential solutions. This review provides an application-oriented design roadmap for linking zwitterionic chemistry, polymer synthesis, material architecture, and biomedical translation.