Thermosensitive Triblock Copolymer for Slow-Release Lubricants under Ocular Conditions

Abstract

The ocular environment is crucial for a biological lubrication system. An unstable condition of tear film may cause a series of ocular diseases due to serious friction, such as dry eye syndrome, which has drawn extensive attention nowadays. In this study, an in vitro biocompatible superlubricity system, containing thermogelling copolymers (PCGA−PEG−PCGA) and slow-release lubricant (PEG 300/Tween 80), was constructed. First, the sol−gel transition temperature and gel strength of PCGA− PEG−PCGA were adjusted based on the ocular environment by regulating the length of PCGA blocks. Furthermore, the copolymer hydrogel exhibited a reliable slowrelease property within 10 days and showed low cytotoxicity. Then, the superlubricity (coefficient of friction of approximately 0.005) was achieved with its released PEG 300/Tween 80 aqueous solution at the sliding velocity range of 1−100 mm s −1 and pressure range of 10−22 kPa. However, the lubrication behaviors varied, while PEG 300 chains and Tween 80 micelles were demonstrated to form a multilayer and a single layer adsorption structure on the sliding surface, respectively. On the whole, the composite lubrication systems, especially the one composed of Tween 80, showed excellent tribological properties owing to the stable slow-release and full hydration effects under ocular conditions, which hold great potential for improving ocular lubrication and maintaining human visual health.

Multifunctional Cerium Oxide Nanozyme for Synergistic Dry Eye Disease Therapy

“…Major changes in tear film structure and function are important features of DED . The tear film instability caused by excessive tear evaporation leads to the disturbance of ocular surface homeostasis, which is involved in the pathogenesis of DED. , Certain Asian nations, including China and Japan, have approved diquafosol sodium (DQS) ophthalmic solution as a first-line treatment for DED to improve tear film stability and dry eye symptoms . DQS, a dinucleotide derivative of UTP, is a direct agonist of the purinergic P2Y 2 receptor that stimulates the conjunctiva to secrete water and mucin. , Research has found that the P2Y 2 receptor was closely related to DED .…”