Reduced Silicone Oil Adherence to Silicone Intraocular Lens by Surface Modification with 2-Methacryloyloxyethyl Phosphoryl-Choline

Research Progress Concerning a Novel Intraocular Lens for the Prevention of Posterior Capsular Opacification

Posterior capsular opacification (PCO) is the most common complication resulting from cataract surgery and limits the long-term postoperative visual outcome. Using Nd:YAG laser-assisted posterior capsulotomy for the clinical treatment of symptomatic PCO increases the risks of complications, such as glaucoma, retinal diseases, uveitis, and intraocular lens (IOL) pitting. Therefore, finding how to prevent PCO development is the subject of active investigations. As a replacement organ, the IOL is implanted into the lens capsule after cataract surgery, but it is also associated with the occurrence of PCO. Using IOL as a medium for PCO prophylaxis is a more facile and efficient method that has demonstrated various clinical application prospects. Thus, scientists have conducted a lot of research on new intraocular lens fabrication methods, such as optimizing IOL materials and design, and IOL surface modification (including plasma/ultraviolet/ozone treatment, chemical grafting, drug loading, coating modification, and layer-by-layer self-assembly methods). This paper summarizes the research progress for different types of intraocular lenses prepared by different surface modifications, including anti-biofouling IOLs, enhanced-adhesion IOLs, micro-patterned IOLs, photothermal IOLs, photodynamic IOLs, and drug-loading IOLs. These modified intraocular lenses inhibit PCO development by reducing the residual intraoperative lens epithelial cells or by regulating the cellular behavior of lens epithelial cells. In the future, more works are needed to improve the biosecurity and therapeutic efficacy of these modified IOLs.

Recent Advances of Intraocular Lens Materials and Surface Modification in Cataract Surgery

Advances in cataract surgery have increased the demand for intraocular lens (IOL) materials. At present, the progress of IOL materials mainly contains further improving biocompatibility, providing better visual quality and adjustable ability, reducing surgical incision, as well as dealing with complications such as posterior capsular opacification (PCO) and ophthalmitis. The purpose of this review is to describe the research progress of relevant IOL materials classified according to different clinical purposes. The innovation of IOL materials is often based on the common IOL materials on the market, such as silicon and acrylate. Special properties and functions are obtained by adding extra polymers or surface modification. Most of these studies have not yet been commercialized, which requires a large number of clinical trials. But they provide valuable thoughts for the optimization of the IOL function.

A transparent hydrophilic anti-biofouling coating for intraocular lens materials prepared by "bridging" of the intermediate adhesive layer

The attachment of bio-foulants, including unwanted cells, proteins, and bacteria, to a medical device such as an intraocular lens can lead to implantation failure. Hydrophilic polymers are often used as surface modifiers in the fabrication of anti-biofouling coatings, but a hydrophilic coating can easily become swollen and peel off the substrate. In this study, we chose polymethyl methacrylate (PMMA) as the representative material of intraocular lenses because PMMA has better biocompatibility, a higher refractive index, better optical clarity, lighter weight, more stable performance, and lower cost than other intraocular lens materials. We fabricated polyvinyl alcohol (PVA) coatings with or without a "bridge", that is, an intermediate adhesive layer (AL), to increase the adhesion bonding effect between the anti-biofouling coating and the substrate. The results indicated that the prepared coatings were transparent and noncytotoxic. Moreover, the anti-adhesion properties of the cells and the resistance properties to nonspecific protein adsorption of PMMA modified by both AL and PVA coatings were better and more durable compared with the sample only modified with a physically dipped PVA coating. The coating prepared by AL "bridging" provides a new strategy for the preparation of a transparent hydrophilic anti-biofouling coating suitable for PMMA intraocular lens materials.

Surface Modification of Intraocular Lens with Hydrophilic Poly(Sulfobetaine Methacrylate) Brush for Posterior Capsular Opacification Prevention

Purpose: The intraocular lens (IOL) is a common, yet important, implantable device used in treatment of cataract in clinics. However, the unexpected adhesion of postoperative residual lens epithelial cells (LECs) often causes serious complications, such as posterior capsular opacification (PCO), which lead to vision loss again. In this investigation, a poly(sulfobetaine methacrylate) (PSBMA) brush coating was fabricated on an IOL to generate a hydrophilic surface coating on the IOL for enhanced cell adhesion resistance so as to decrease PCO incidence. Methods: The PSBMA brush coating on the IOL surface was fabricated using surface-initiated reversible addition-fragmentation chain transfer polymerization. X-ray photoelectron spectroscopy (XPS) was used to demonstrate the surface coating preparation. The water contact angle (WCA) measurement was used to test surface hydrophilicity. In vitro LEC culture was use to evaluate the cell behavior on the IOL material surfaces, with or without PSBMA coating modification. Finally, animal cataract surgeries were carried out to evaluate in vivo biocompatibilities and anti-PCO effects. Results: The XPS and WCA measurements illustrate successful surface modification and good surface hydrophilicity. The in vitro cell culture results show that the hydrophilic PSBMA polymer brush coating evidently decreases adhesion and proliferation of LECs. Results of the in vivo cataract surgery with intraocular implantation show that PSBMA modification on the IOL surface does not induce side effects in nearby tissues, whereas posterior capsular hyperplasia can be evidently reduced. Conclusion: The PSBMA brush surface-modified IOL has good in vivo biocompatibility and it can effectively reduce the incidence of postoperative PCO.

Surface Modification of Intraocular Lenses

Objective:

This paper aimed to review the current literature on the surface modification of intraocular lenses (IOLs).

Data Sources:

All articles about surface modification of IOLs published up to 2015 were identified through a literature search on both PubMed and ScienceDirect.

Study Selection:

The articles on the surface modification of IOLs were included, but those on design modification and surface coating were excluded.

Results:

Technology of surface modification included plasma, ion beam, layer-by-layer self-assembly, ultraviolet radiation, and ozone. The main molecules introduced into IOLs surface were poly (ethylene glycol), polyhedral oligomeric silsesquioxane, 2-methacryloyloxyethyl phosphorylcholine, TiO₂, heparin, F-heparin, titanium, titanium nitride, vinyl pyrrolidone, and inhibitors of cytokines. The surface modification either resulted in a more hydrophobic lens, a more hydrophilic lens, or a lens with a hydrophilic anterior and hydrophobic posterior surface. Advances in research regarding surface modification of IOLs had led to a better biocompatibility in both in vitro and animal experiments.

Conclusion:

The surface modification is an efficient, convenient, economic and promising method to improve the biocompatibility of IOLs.

Improvement of Uveal and Capsular Biocompatibility of Hydrophobic Acrylic Intraocular Lens by Surface Grafting with 2-Methacryloyloxyethyl Phosphorylcholine-Methacrylic Acid Copolymer

Biocompatibility of intraocular lens (IOL) is critical to vision reconstruction after cataract surgery. Foldable hydrophobic acrylic IOL is vulnerable to the adhesion of extracellular matrix proteins and cells, leading to increased incidence of postoperative inflammation and capsule opacification. To increase IOL biocompatibility, we synthesized a hydrophilic copolymer P(MPC-MAA) and grafted the copolymer onto the surface of IOL through air plasma treatment. X-ray photoelectron spectroscopy, atomic force microscopy and static water contact angle were used to characterize chemical changes, topography and hydrophilicity of the IOL surface, respectively. Quartz crystal microbalance with dissipation (QCM-D) showed that P(MPC-MAA) modified IOLs were resistant to protein adsorption. Moreover, P(MPC-MAA) modification inhibited adhesion and proliferation of lens epithelial cells (LECs) in vitro. To analyze uveal and capsular biocompatibility in vivo, we implanted the P(MPC-MAA) modified IOLs into rabbits after phacoemulsification. P(MPC-MAA) modification significantly reduced postoperative inflammation and anterior capsule opacification (ACO), and did not affect posterior capsule opacification (PCO). Collectively, our study suggests that surface modification by P(MPC-MAA) can significantly improve uveal and capsular biocompatibility of hydrophobic acrylic IOL, which could potentially benefit patients with blood-aqueous barrier damage.

Bottom-up fabrication of zwitterionic polymer brushes on intraocular lens for improved biocompatibility

Intraocular lens (IOL) is an efficient implantable device commonly used for treating cataracts. However, bioadhesion of bacteria or residual lens epithelial cells on the IOL surface after surgery causes postoperative complications, such as endophthalmitis or posterior capsular opacification, and leads to loss of sight again. In the present study, zwitterionic polymer brushes were fabricated on the IOL surface via bottom-up grafting procedure. The attenuated total reflection-Fourier transform infrared and contact angle measurements indicated successful surface modification, as well as excellent hydrophilicity. The coating of hydrophilic zwitterionic polymer effectively decreased the bioadhesion of lens epithelial cells or bacteria. In vivo intraocular implantation results showed good in vivo biocompatibility of zwitterionic IOL and its effectiveness against postoperative complications.

Surface PEGylation of intraocular lens for PCO prevention: An in vivo evaluation

Posterior capsular opacification (PCO) is a common complication in cataract surgery. The development of PCO is attributed to the combination of adhesion, migration, proliferation, and transdifferentiation of the residual lens epithelial cells (LEC) onto the interface of intraocular lens (IOL) material and lens posterior, in which the initial adhesion is the beginning step and plays important roles. In the present study, hydrophilic polyethylene glycol (PEG) was immobilized onto IOL surface via plasma-aided chemical grafting procedure. The attenuated total reflection - Fourier transform infrared (ATR-FTIR) and contact angle (CA) - measurements indicate the successful surface PEGylation, as well as the excellent hydrophilicity of the surfaces. Compared with pristine IOL, the PEGylation does not influent its optical property, whereas the initial adhesion of LEC is greatly inhibited. In vivo ocular implantation results show that the PEGylated IOL presents good in vivo biocompatibility, and can effectively prevent the PCO development.