Two-electron oxidized polyphenol chemistry-inspired superhydrophilic drug-carrying coatings for the construction of multifunctional nasolacrimal duct stents.

Nasolacrimal duct obstruction due to infection, inflammation, or excessive fibroblast proliferation may result in persistent tearing, intraocular inflammation, or even blindness. In this study, surface engineering techniques are applied to nasolacrimal duct stents for the first time. Based on the functioning of marine mussels, "one-pot" and "stepwise" methods were employed to construct a novel multifunctional superhydrophilic PDA/RAP coating using dopamine and rapamycin. Micron-sized rapamycin crystals combined with nano-sized polydopamine particles form a micro-nano topographical structure. Therefore, acting synergistically with in situ -generated hydrophilic groups (amino, carboxyl, and phenolic hydroxyl), they impart excellent and long-lasting superhydrophilicity to the nasolacrimal duct stent. The PDA/RAP coating effectively maintained the stability of the initial microenvironment during stent implantation by inhibiting the onset of acute inflammation and infection during the early stages of implantation. Meanwhile, the rapamycin crystals, supported by the superhydrophilic platform, exhibited a sustained-release capability that helped them to better exert their anti-inflammatory, antibacterial, and anti-fibroblast proliferative properties, ensuring conducive conditions for the rapid repair of nasolacrimal duct epithelial cells, verified by a series of experiments. In conclusion, the PDA/RAP hydrophilic coating has anti-inflammatory, antifibrotic, antibacterial, and antithrombotic properties, offering a new strategy to address restenosis following clinical nasolacrimal duct stent implantation.