Cellular Microenvironment-Sensitive Drug Eluting Coating on Intraocular Lens for Enhanced Posterior Capsular Opacification Prevention and in Vivo Biocompatibility

Cascade catalytic multilayer modified intraocular lens for enhanced and safer posterior capsule opacification prevention

Posterior capsule opacification (PCO) is the most common complication after cataract surgery. It is primarily caused by the proliferation, migration, and adhesion of residual lens epithelial cells within the capsular bag following phacoemulsification and intraocular lens (IOL) implantation. Although investigations of surface modification onto IOL have partially reduced PCO development in recent years, there are still challenges in long-term efficacy and intraocular biocompatibility. In this study, a cascade catalytic system is constructed using natural enzymes onto mesoporous silica nanoparticles (MSNs), which are subsequently fixed to the surface of IOL through layer-by-layer self-assemble of alternating positive and negative charges. The cascade catalytic reaction is trigged simply by glucose within the pouch to produce reactive oxygen species (ROS) without introducing any toxic drugs or external energy, attempting to minimize the possible toxic side effects to surrounding tissues. In vivo and in vitro experiments indicate the effective inhibition of PCO and favorable intraocular compatibility of the cascade catalytic platform modified IOL. More importantly, the modified IOL retains good optical performance and imaging quality, demonstrating promising prospects for application. This study provides a new possibility for enhanced and safer PCO prevention, playing great significance in clinical treatment. STATEMENT OF SIGNIFICANCE: Cascade catalytic nanoparticles-loaded multilayer modified IOL is obtained via LbL technique. The multilayer coating improves both the loading capacity and the activity of the cascade catalytic nanoparticles. The cascade catalytic reaction is trigged by glucose, producing ROS that efficiently induces apoptosis and death of remaining cells on IOL without introducing any toxic drugs or external energy. The innovative IOL provides a promising approach for enhanced and safer prevention of PCO.

Mitigation of pesticide-mediated ocular toxicity via nanotechnology-based contact lenses: a review

The xenobiotic stress exerted by pesticides leads to the deterioration of human and animal health including ocular health. Acute or prolonged exposure to these agricultural toxicants has been implicated in a number of pathological conditions of the eye such as irritation, epiphora or hyper-lacrimation, abrasions on the ocular surface, and decreased visual acuity. The issue is compounded by the fact that tissues of the eye absorb pesticides faster than other organs of the body and are more susceptible to damage as well. However, there is a lacuna in our knowledge regarding the ways by which pesticide exposure-mediated ocular insult might be counteracted. Topical instillation of drugs known to combat the pesticide induced toxicity has been explored to mitigate the detrimental impact of pesticide exposure. However, topical eye drop solutions exhibit very low bioavailability and limited drug residence duration in the tear film decreasing their efficacy. Contact lenses have been explored in this respect to increase bioavailability of ocular drugs, while nanoparticles have lately been utilized to increase drug bioavailability and increase drug residence duration in different tissues. The current review focuses on drug delivery and futuristic aspects of corneal protection from ocular toxicity using contact lenses.

Mild Photothermal Therapy Prevents Posterior Capsule Opacification through Cytoskeletal Remodeling

Cataract is the first leading cause of blindness in the world and posterior capsule opacification (PCO) is the most common long-term complication after surgery. The primary pathogenic processes contributing to PCO are the proliferation and migration of residual lens epithelial cells (LECs). This study aimed to explore the mild photothermal effect on LECs. Interestingly, this work finds that the mild photothermal effect significantly inhibited the proliferation and migration of LECs. The live cell fluorescence imaging reveals that the remodeling of the actin cytoskeleton and cell morphology attributed to the inhibition effect. Further mechanistic studies at molecular level suggest that the mild photothermal effect can regulate the phosphorylation of ERM, YAP, and Cofilin and thereby affect the proliferation and migration of LECs. In order to explore the potential clinical application of mild photothermal therapy for PCO prevention, PDA/PVA gel rings with photothermal effect is prepared by the repeated freeze-thaw method and conducted experiments in vivo, which achieved favorable PCO prevention effect. Overall, this study shows that the mild photothermal effect can regulate the proliferation and migration of LECs through cytoskeletal remodeling and the results of experiments in vivo demonstrate that mild photothermal effect is a promising approach for PCO prevention.

Augmented cellular uptake and homologous targeting of exosome-based drug loaded IOL for posterior capsular opacification prevention and biosafety improvement

Posterior capsular opacification (PCO), the most common complication after cataract surgery, is caused by the proliferation, migration and differentiation of residual lens epithelial cells (LECs) on the surface of the intraocular lens (IOL). Although drug-loaded IOLs have been successfully developed, the PCO prevention efficacy is still limited due to the lack of targeting and low bioavailability. In this investigation, an exosome-functionalized drug-loaded IOL was successfully developed for effective PCO prevention utilizing the homologous targeting and high biocompatibility of exosome. The exosomes derived from LECs were collected to load the anti-proliferative drug doxorubicin (Dox) through electroporation and then immobilized on the aminated IOLs surface through electrostatic interaction. In vitro experiments showed that significantly improved cellular uptake of Dox@Exos by LECs was achieved due to the targeting ability of exosome, compared with free Dox, thus resulting in superior anti-proliferation effect. In vivo animal investigations indicated that Dox@Exos-IOLs effectively inhibited the development of PCO and showed excellent intraocular biocompatibility. We believe that this work will provide a targeting strategy for PCO prevention through exosome-functionalized IOL.

Rapid and Economical Drug-Eluting IOL Preparation via Thermoresponsive Agarose Coating for Effective Posterior Capsular Opacification Prevention

Posterior capsular opacification (PCO), the highest incidence complication after cataract surgery, is mainly due to the attachment, proliferation, and migration of the residual lens epithelial cells (LECs). Although the drug-eluting IOLs have been proved to be an effective way to prevent PCO incidence, its preparations are time consuming and require tedious preparation steps. Herein, the thermoreversible agarose is adopted to prepare drug-eluting IOL. Such functional coating can be obtained easily by simple immersion in the antiproliferative drug containing hot agarose and taken out for cooling, which not only does not affect the optical property but also can effectively decrease the PCO incidence after intraocular implantation. As a result, the proposed agarose coating provides a rapid and economical alternative of drug-eluting IOL fabrication for PCO prevention.

Nanoporous Gold Ring-Integrated Photothermal Intraocular Lens for Active Prevention of Posterior Capsular Opacification

Posterior capsular opacification (PCO) is the leading complication after cataract surgery, and is mainly induced by the proliferation and migration of residual lens epithelial cells (LECs). Although numerous attempts have been made to reduce the incidence of PCO, this complication remains a critical challenge in postoperative visual recovery. This study aims to report a functionalized intraocular lens (R-IOL) with a region-confined photothermal effect for the active prevention of PCO after implantation. The outer rim of R-IOL (non-optical area) is decorated with a nanoporous gold (NPG) ring, which can effectively eliminate the LECs around R-IOL, ultimately inhibiting the migration of LECs from the periphery to the visual axis center in the initial stage, and preventing the subsequent PCO. Furthermore, the mechanism of LECs elimination can be attributed to apoptosis induced by mild photothermal therapy. After in vivo implantation for 30 days, PCO is rarely observed in the R-IOL group, whereas the considerably higher incidence of PCO (75%) is found in the pristine IOL (P-IOL) group. The region-confined photothermal effect based on NPG not only provides an active strategy to effectively prevent PCO, but also introduces new opportunities for the treatment of undesirable hyperplasia.

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.

Lab-on-a-Contact Lens: Recent Advances and Future Opportunities in Diagnostics and Therapeutics

The eye is one of the most complex organs in the human body, containing rich and critical physiological information (e.g., intraocular pressure, corneal temperature, and pH) as well as a library of metabolite biomarkers (e.g., glucose, proteins, and specific ions). Smart contact lenses (SCLs) can serve as a wearable intelligent ocular prosthetic device capable of noninvasive and continuous monitoring of various essential physical/biochemical parameters and drug loading/delivery for the treatment of ocular diseases. Advances in SCL technologies and the growing public interest in personalized health are accelerating SCL research more than ever before. Here, the current status and potential of SCL development through a comprehensive review from fabrication to applications to commercialization are discussed. First, the material, fabrication, and platform designs of the SCLs for the diagnostic and therapeutic applications are discussed. Then, the latest advances in diagnostic and therapeutic SCLs for clinical translation are reviewed. Later, the established techniques for wearable power transfer and wireless data transmission applied to current SCL devices are summarized. An outlook, future opportunities, and challenges for developing next-generation SCL devices are also provided. With the rise in interest of SCL development, this comprehensive and essential review can serve as a new paradigm for the SCL devices.

Foldable Bulk Anti-adhesive Polyacrylic Intraocular Lens Material Design and Fabrication for Posterior Capsule Opacification Prevention

Posterior capsular opacification (PCO) is a primary complication after phacoemulsification combined with intraocular lens (IOL) implantation, which is attributed to adhesion, proliferation, and migration of residual lens epithelial cells on IOL. Although surface hydrophilic coating is considered to be a powerful way to inhibit PCO incidence after surgery, it requires complex post-production processes, thus limiting their applicability. In comparison, bulk modification is a stable, effective, and facile IOL synthesis method for PCO prevention. Herein, a new anti-adhesive IOL material was designed and successfully synthesized by radical copolymerization of ethylene glycol phenyl ether methacrylate (EGPEMA) and 2-(2-ethoxyethoxy) ethyl acrylate (EA). The physicochemical properties of P(EGPEMA-co-EA) copolymer materials, including chemical structure, mechanical, thermal, surface, and optical properties, were analyzed by using ¹H NMR spectroscopy, FT-IR spectroscopy, tensile test, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), water contact angle measurement, and UV-vis spectroscopy. The elongation at break and the modulus of elasticity of the copolymer were tunable through the change of the composition of monomers. Compared to other components, the tensile results showed that P(EGPEMA-co-EA) materials (70% EGPEMA in mass ratio, F7) are suitable for the preparation of foldable intraocular lens with lower elastic modulus and higher elongation at break. TGA and DSC showed that the material has high thermal stability, and the glass transition temperature of F7 material is 16.1 °C. The water contact angle measurement results showed that the introduction of EA improved the hydrophilicity of the material. The percentage of transmittance of all copolymers at 400-800 nm is above 85%. Then, the biocompatibility of the materials was evaluated by in vitro assay and subcutaneous implantation. Both in vitro results and subcutaneous implantation experiments showed that the designed IOL materials exhibited a good anti-adhesion effect and no cytotoxicity. Finally, phacoemulsification and IOL intraocular implantation were performed, and the in vivo results confirmed the good PCO prevention ability as well as the biocompatibility of the new IOL materials.

Surface Self-Assembly Construction of Therapeutic Contact Lens with Bacterial "Kill-Releasing" and Drug-Reloading Capabilities for Efficient Bacterial Keratitis Treatment

Bacterial keratitis, an ophthalmic emergency, can cause corneal perforation and even endophthalmitis, thus leading to severe visual impairment. To achieve effective treatment of bacterial keratitis, good bioavailability of antimicrobial drugs on the ocular surface is desired. In this investigation, a layer-by-layer (LBL) self-assembly combined with the host-guest recognition was used to construct an antibacterial coating on the surface of corneal contact lens (CLs) to improve drug bioavailability and achieve successful treatment of bacterial keratitis. First, a radical copolymerization of acrylic acid (AA) and 1-adamantan-1-ylmethyl acrylate (AdA) was carried out to synthesize a polyanionic copolymer P(AA-co-AdA) (defined as PAcA). Then, PAcA copolymer combined with poly(ethyleneimine) (PEI) was used for a layer-by-layer (LBL) self-assembly to fabricate multilayer films on the surface of CLs. An antibacterial conjugate, β-cyclodextrin-levofloxacin (β-CD-LEV), was successfully synthesized and utilized to generate antibacterial coating through a host-guest interaction between AdA and β-CD-LEV. The antibacterial ability and treatment effect of bacterial keratitis was evaluated by in vitro assay and in vivo test in an animal model of staphylococcal keratitis, demonstrating that the antibacterial coating had good antibacterial and germicidal efficacy both in vivo and in vitro. We believe that this work will provide a promising strategy for the treatment of bacterial keratitis.

Commercial soft contact lenses engineered with zwitterionic silver nanoparticles for effectively treating microbial keratitis

The introduction of various drugs onto commercial soft contact lenses (CLs) has emerged as a potentially effective strategy for treating microbial keratitis (MK) because drug-loaded CLs can maintain a controlled drug concentration which leaded to enhanced drug bioavailability and reduced side effects in ocular tissues. In this study, silver nanoparticles modified with zwitterionic poly (carboxybetaine-co-dopamine methacrylamide) copolymer (PCBDA@AgNPs) as novel anti-infective therapeutics were prepared and firmly immobilized onto soft CLs through mussel-inspired surface chemistry. The obtained PCBDA@AgNPs coated CL (PCBDA@AgNPs-CL) remained the excellent transparency of commercial CLs and exhibited strong and broad-spectrum antimicrobial activities. We systematically explored the mechanism and found that the functional CLs can effectively inhibit the growth of microbial biofilms via a synergic "resist-kill-remove" strategy due to the zwitterionic surface and sustained release of silver ions. Significantly, in vitro cell cytotoxicity and in vivo subcutaneous implantation experiments proved the significant biosafety of PCBDA@AgNPs-CL. Furthermore, PCBDA@AgNPs-CL was successfully employed for the in vivo treatment of MK rabbit models, demonstrating excellent abilities to eradicate microbe-induced ocular infections and to prevent the destruction and irreversible structural alterations of corneal tissues. Collectively, PCBDA@AgNPs-CL is therefore a highly promising therapeutic device to significantly boost the efficacy for MK treatment.

Preparation of 5-fluorouracil loaded chitosan microtube via in situ precipitation for glaucoma drainage device application: in vitro and in vivo investigation

The main reason for the failure of glaucoma drainage devices is the chronic inflammatory reaction caused by the poor biocompatibility of biomaterials, which leads to the migration and proliferation of scleral fibroblasts surrounding the devices thus forming the encapsulation that will block the aqueous humor drainage channel. In order to inhibit the reaction of scleral fibroblasts after glaucoma drainage device implantation, this study designed and fabricated a 5-fluorouracil (5-FU) loaded chitosan microtube (CMT) for glaucoma aqueous humor drainage. The CMTs were made by template based adsorption-precipitation method using chitosan with excellent biocompatibility as raw material due to its characteristic of pH dependent solubility. The physical properties of CMTs were investigated. The in vitro and in vivo biocompatibilities were studied as well. The developed drainage device is expected to possess the dual function of reducing intraocular pressure and inhibiting excessive fibrosis after glaucoma drainage device implantation, thereby providing a novel way for the research of glaucoma drainage devices.

Surface modification of intraocular lenses via photodynamic coating for safe and effective PCO prevention

Posterior capsular opacification (PCO) is an emerging complication in cataract phacoemulsification and intraocular lens (IOL) implantation surgery, mainly stemming from the adhesion, proliferation, and trans-differentiation of the post-surgery residual lens epithelial cells (LECs). Previous investigations have shown that an anti-proliferative drug eluting coating on the IOL surface provides an effective way to inhibit PCO. However, due to the undesirable elution of the anti-proliferative drug, the safety of such modification is one of the important issues to be solved. In this investigation, photodynamic coating was introduced into IOL surface modification. The photosensitizer chlorin e6 grafted α-cyclodextrin (α-CD-Ce6) was synthesized and self-assembled onto the poly(poly(ethylene glycol) methacrylate) (PPEGMA) brush established IOL surface via the supramolecular interaction between α-CD and poly(ethylene glycol) chains. The results of investigation into its optical properties, including transmittance, refractive index, and surface morphology, showed no obvious alterations after photodynamic coating modification on the IOL surface. The in vitro LEC behaviour investigation optimized the photodynamic therapy parameters when light illumination was used for the cell elimination on the photodynamic coating modified IOL. The results have also shown that this functional coating modification effectively eliminates the cells on the surface of the IOL material when treated with light illumination, whereas it keeps excellent cytocompatibility in the absence of light illumination. The investigation of the cell elimination mechanism shows that this kind of functional coating eliminates the adherent cells by ROS induced apoptosis. The in vivo implantation result confirms the excellent PCO inhibition effect, as well as their safety and biocompatibility to the surrounding tissues. As a result, the proposed photodynamic coating provides a safer and effective alternative of IOL modification for preventing PCO.

Drug-Eluting Hydrophilic Coating Modification of Intraocular Lens via Facile Dopamine Self-Polymerization for Posterior Capsular Opacification Prevention

Posterior capsular opacification (PCO) is the most important complication in cataract phacoemulsification and intraocular lens (IOL) implantation surgery, mainly stemming from the adhesion, proliferation, and transdifferentiation of the postsurgically residual lens epithelial cells (LECs). Previous investigations mainly focused on the hydrophilic surface modification of the IOLs for PCO prevention, such as heparinization. However, the long-term clinical investigations show that there is no significant difference between pristine and heparinized IOLs. In the present study, a synergetic coating with properties of drug-eluting and hydrophilicity was designed and modified onto the IOL surface via facile dopamine self-polymerization. The antiproliferative drug doxorubicin (DOX) was loaded when a polydopamine (PDA) coating was formed on the IOL surface. The hydrophilic 2-methacryloyloxyethyl phosphorylcholine (MPC) could be subsequently grafted onto the drug-loaded PDA coating surface easily. The hydrophilic outer layer could slow down drug-eluting from underneath the drug-incorporated coating. In vitro and in vivo investigations demonstrated that such multifunctionalized coating-modified IOLs could not only thoroughly and effectively prevent PCO development by induced cell apoptosis but also render safety and biocompatibility to the surrounding tissues.

Antiproliferative drug-loaded multi-functionalized intraocular lens for reducing posterior capsular opacification

Posterior capsule opacification (PCO) is one of the most frequent complications in cataract surgery and likely to cause the second loss of vision. Proliferation and migration of postoperative remnants of lens epithelial cells (LECs) on the implanted intraocular lens (IOL) are the leading causes of PCO. Antiproliferative drugs can be an effective solution but also possess some problems including sudden release and accompanying adverse effects to surrounding normal tissues, which greatly limit the clinical trials. In this study, an antiproliferative drug Paclitaxel (Pac) -sustained released hyaluronic acid (HA) and chitosan (CHI) multilayer modified IOL with postoperatively long-term PCO prevention was fabricated via layer by layer (LbL) technique. Quartz crystal microbalance with dissipation monitoring (QCM-D) result shows that HA-Pac/CHI multilayer is modified onto IOL material via LbL technique successfully. The HA-Pac/CHI multilayer coating greatly improves the hydrophilicity of the IOL material surfaces without change the transmittance significantly, whereas the proliferation of LECs is distinctly reduced on the HA-Pac/CHI multilayer-modified surfaces. The drug release in vitro reveals that the multilayer modified IOL material is stable under physiological condition and has good sustained drug release property. All these results demonstrate that HA-Pac/CHI multilayer modified IOL material can effectively inhibit LECs proliferation which provides a novel approach for reducing of PCO incidence in clinical.