# Photothermal and cascade ROS generative multilayer as intraocular lens surface coating for effective posterior capsular opacification inhibition

## TL;DR

This paper introduces a new intraocular lens coating that uses gold nanoparticles and metal-organic frameworks to prevent a common post-surgery complication by generating reactive oxygen species and heat.

## Contribution

A novel multilayer coating using AuNPs@MIL for IOLs that combines photothermal therapy and ROS generation to inhibit posterior capsular opacification.

## Key findings

- AuNPs@MIL coating effectively inhibits HLEC proliferation and migration in vitro and in vivo.
- The coating demonstrates good biocompatibility and optical properties suitable for intraocular use.
- NIR-induced photothermal therapy enhances cell apoptosis for long-term PCO prevention.

## Abstract

Cataract is the leading cause for blindness. While the intraocular lens (IOL) implantation is the only effective treatment in cataract surgery. Posterior capsule opacification (PCO) is the most frequent complication after cataract surgery, mainly resulting from the proliferation and migration of residual human lens epithelial cells (HLECs) within the capsular bag. While surface modification of IOL has helped slow its progression, long-term effectiveness and biocompatibility remain major challenges. Supraphysiological concentration of reactive oxygen species (ROS) induced by natural enzyme stimulation can effectively inhibit proliferation and migration of HLECs, but the effect is limited by enzyme instability. Gold nanoparticles (AuNPs), a promising candidate with enzyme-mimicking activity and desirable photothermal effects, can promote ROS generation and enhance cell apoptosis. To prevent AuNPs aggregation, Fe3+ containing MIL metal-organic frameworks (MOFs) were used as a supporting framework to obtain AuNPs@MIL, which was then modified onto IOL material via electrostatic layer by layer (LbL) self-assembly technique to improve stability and increase immobilization efficiency. The cascade catalytic process, initiated by AuNPs@MIL, can catalyze glucose and oxygen oxidation to produce gluconic acid and hydrogen peroxide. In the formed acidic environment, AuNPs, along with Fe3+ from MIL, convert H2O2 into ·OH via oxidase-like and Fenton-type reactions, which will accelerate cell apoptosis. Additionally, NIR-induced photothermal therapy (PTT) of AuNPs further eliminates abnormally proliferating cells. In vitro and in vivo studies demonstrate that AuNPs@MIL modified IOL offers effective PCO prevention effect, good biocompatibility and excellent optical properties, presenting a viable solution for long-term, efficient PCO prevention.

Graphical Abstract