A chain entanglement-stabilized injectable zwitterionic polymer hydrogel: Towards long-term vitreous substitute application
image: (A) Schematic illustration of chain entanglement-mediated zwitterionic polymer hydrogels. With increasing monomer concentration, chain entanglement density transitions from loose to high, resulting in enhanced mechanical properties ranging from dissociation to injectability and self-standing integrity. (B) Schematic of injectable zwitterionic polymer hydrogel application for vitreous replacement. Following retinal detachment, the shear-thinning hydrogel is injected to provide tamponade, offering vitreous-like viscoelasticity, antifouling properties, and long-term intraocular stability.
Credit: ©Science China Press
Many vitreoretinal disorders, including retinal detachment (rhegmatogenous, exudative, or tractional), macular holes, proliferative vitreoretinopathy, diabetic retinopathy, and vitreous hemorrhage, often require vitrectomy with retinal repair, followed by intraocular tamponade to stabilize the retina and preserve ocular integrity. The tamponade agents most used in clinical practice are expansile gases and silicone oil. Although these materials can effectively support postoperative retinal reattachment, they remain limited in terms of long-term stability and biosafety. Complications such as cataract formation, elevated intraocular pressure, intraocular inflammation, and retinal injury associated with silicone oil emulsification may still occur.
To address this challenge, Prof. Jianhai Yang and Prof. Wenguang Liu (Tianjin University), together with Prof. Xiaorong Li and Prof. Xiaoli Xing (Tianjin Medical University Eye Hospital) developed an injectable zwitterionic polymer hydrogel based on poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC). The hydrogel does not require additional chemical crosslinkers. Instead, its stable network structure is formed and maintained through topological chain entanglements. Taking advantage of its shear-thinning behavior, the PMPC hydrogel can be delivered into the vitreous cavity through minimally invasive injection. During a six-month postoperative follow-up in a rabbit vitrectomy model, the hydrogel demonstrated favorable intraocular tolerability and biocompatibility, together with sustained optical and functional stability. The findings were published in National Science Review.
The team further evaluated the tamponade performance of the PMPC hydrogel in a rabbit model of rhegmatogenous retinal detachment, focusing on its ability to maintain continuous coverage of retinal breaks and support sustained retinal reattachment. Notably, PMPC-based materials already have a foundation in clinical applications, mature industrial supply chains, and relevant regulatory precedents. These advantages may reduce the complexity associated with subsequent manufacturing and clinical translation, potentially facilitating earlier clinical evaluation of the hydrogel as a practical alternative to silicone oil.