Tissue‐reactive graft copolymers were designed to protect the cartilage against enzymatic degradation and restore its lubrication properties during the early stages of osteoarthritis (OA). The copolymers feature a poly(glutamic acid) (PGA) backbone bearing hydroxybenzaldehyde (HBA) functions and cyclic poly(2‐methyl‐2‐oxazoline) (PMOXA) side chains. PGA‐PMOXA‐HBA species chemisorb on the degraded tissue via Schiff bases and expose the biopassive and lubricious PMOXA cyclic grafts at the interface. The smaller hydrodynamic radius by cyclic PMOXA side chains coupled to the intrinsic absence of chain ends generate denser and more lubricious films on cartilage when compared to those produced by copolymers bearing linear PMOXA. Topology effects demonstrate how the introduction of cyclic polymers within tissue‐reactive copolymers substantially improve their tribological and biopassive properties, suggesting a plethora of possible applications for cyclic macromolecules in biomaterials formulations.

中文翻译：

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润滑和保护受损软骨的环状聚合物接枝

组织反应性接枝共聚物旨在保护软骨免于酶促降解，并在骨关节炎（OA）的早期恢复其润滑性能。该共聚物具有带有羟基苯甲醛（HBA）功能和环状聚（2-甲基-2-恶唑啉）（PMOXA）侧链的聚谷氨酸（PGA）主链。PGA-PMOXA-HBA物种通过Schiff碱化学吸附在降解的组织上，并在界面处暴露生物钝性和润滑性的PMOXA环状移植物。与带有线性PMOXA的共聚物所制得的膜相比，环状PMOXA侧链所具有的较小的流体力学半径，再加上固有的不存在链端，在软骨上产生了致密且润滑的膜。