Engineering an injectable and tunable hydrogel as a potential vitreous substitute.

Area of Science:

• Biomaterials Science
• Ophthalmology
• Polymer Chemistry

Background:

• Intraocular endotamponades are crucial for treating retinal detachment and proliferative diabetic retinopathy.
• Current endotamponades face challenges with dispersion and fragmentation, limiting clinical use.
• Developing injectable materials with controlled in situ gelation is essential for vitreous substitution.

Purpose of the Study:

• To create an injectable hydrogel mimicking human vitreous properties for intraocular applications.
• To develop a stable endotamponade with tunable viscosity and in situ gelation.
• To evaluate the in vivo performance and biocompatibility of the novel hydrogel.

Main Methods:

• Synthesized a polyethylene glycol (PEG) hydrogel incorporating high-molecular-weight hyaluronic acid (HA).
• Utilized covalent crosslinking between eight-arm PEG-thiol (8sPEG-SH) and eight-arm PEG-maleimide (8sPEG-MAL).
• Characterized hydrogel properties (storage modulus, gelation time, transparency, surface tension, swelling ratio) and performed in vivo studies in rabbit eyes.

Main Results:

• The PEG-HA hydrogel demonstrated a storage modulus of 15 Pa and tunable in situ gelation in approximately 3 minutes.
• Achieved good optical transparency, appropriate surface tension, and a low swelling ratio.
• In vivo studies confirmed smooth injectability and stable structure formation within the vitreous cavity in rabbit eyes.

Conclusions:

• The developed tunable PEG hydrogel system offers a promising new strategy for vitreous substitutes.
• Controllable in situ gelation via a double-chamber syringe enhances clinical applicability.
• The hydrogel exhibits favorable intraocular biocompatibility and practical operability for ophthalmic applications.