Biomimetic Corneal Stroma for Scarless Corneal Wound Healing via Structural Restoration and Microenvironment Modulation.

Corneal injury-induced stromal scarring causes the most common subtype of corneal blindness, and there is an unmet need to promote scarless corneal wound healing. Herein, a biomimetic corneal stroma with immunomodulatory properties is bioengineered for scarless corneal defect repair. First, a fully defined serum-free system is established to derive stromal keratocytes (hAESC-SKs) from a current Good Manufacturing Practice (cGMP)-grade human amniotic epithelial stem cells (hAESCs), and RNA-seq is used to validate the phenotypic transition. Moreover, hAESC-SKs are shown to possess robust immunomodulatory properties in addition to the keratocyte phenotype. Inspired by the corneal stromal extracellular matrix (ECM), a photocurable gelatin-based hydrogel is fabricated to serve as a scaffold for hAESC-SKs for bioengineering of a biomimetic corneal stroma. The rabbit corneal defect model is used to confirm that this biomimetic corneal stroma rapidly restores the corneal structure, and effectively reshapes the tissue microenvironment via proteoglycan secretion to promote transparency and inhibition of the inflammatory cascade to alleviate fibrosis, which synergistically reduces scar formation by ≈75% in addition to promoting wound healing. Overall, the strategy proposed here provides a promising solution for scarless corneal defect repair.

A polydopamine-based photodynamic coating on the intraocular lens surface for safer posterior capsule opacification conquering.

Intraocular lens (IOL) is the indispensable implant for cataract surgery. However, posterior capsular opacification (PCO) happens in high incidence after IOL implantation. PCO is caused by adhesion, proliferation, and trans-differentiation of the residual human lens epithelial cells (HLECs). Despite the great achievements in surface coating and antiproliferative drug loading on the intraocular lens (IOL) for effective PCO prevention, the complex fabrication process and potential toxicity of the drugs still limit their clinical applications and commercial mass production. In this investigation, a convenient and efficient photodynamic therapy (PDT) coating fabricated by facile yet economical and practical dopamine self-polymerization was applied to IOL surface modification for PCO prevention. The optical properties of IOL, such as light transmittance, imaging quality and refractive index, remain unchanged after modification. Using an in vitro cell assay, the parameters of PDT were optimized. The PDT coating shows excellent biocompatibility in darkness and eliminates LECs significantly under irradiation. The research on the cell elimination mechanism showed that reactive oxygen species (ROS) mainly induced cell apoptosis. In vivo experiments demonstrated that the implantation of modified IOLs can prevent PCO effectively. As a result, this work provides a safe, simple and effective PDT coating for the IOL surface to reduce the incidence of PCO.

Centrifugally concentric ring-patterned drug-loaded polymeric coating as an intraocular lens surface modification for efficient prevention of posterior capsular opacification.

Posterior capsular opacification (PCO) is the main postoperative complication after intraocular lens (IOL) implantation in cataract surgery, because of the proliferation of the residual lens epithelial cells (LECs) in the lens capsule. Drug-eluting IOLs, aimed to develop an in situ drug delivery device, are the promising concept in recent years. As IOLs are optical devices other than implants, the feasibility and applicability remain a challenge for drug-eluting coatings. In this investigation, a centrifugally concentric ring-patterned drug-loaded poly(lactide-co-glycolic acid) (PLGA) coating was designed and fabricated by the spin coating technique. The concentric ring-patterned morphologies and the drug loading and release properties were carefully investigated, and the spin coating parameters were optimized. A concentric annular coating with a thin center and thick periphery was obtained, which was particularly suitable for the surface modification of IOLs, as the visual pathway of the intraocular light transmission greatly requires good light transmittance of the IOLs. IOLs with the immunosuppressant cyclosporin A (CsA)-loaded coating (CsA @ PLGA) modification were then fabricated for PCO prevention. The in vitro LECs culture results showed that the CsA @ PLGA coating-modified IOLs significantly inhibited cell proliferation and induced cell death. Western blot analysis showed that the efficient cell inhibition behavior of CsA was due to the autophagy-mediated cell death pathway. The in vivo intraocular implantation results confirmed the desired PCO inhibition effect. Thus, the centrifugally concentric ring-patterned drug-loaded PLGA coating obtained by the spin coating technique provides a simple yet effective alternative of IOL modification for PCO prevention. STATEMENT OF SIGNIFICANCE: • Concentric ring-patterned polymer coating, specifically for drug-eluting IOL fabrication, was developed by the spin coating technique. • The immunosuppressant CsA inhibited LEC proliferation through the autophagy-mediated cell death pathway. • Concentric ring-patterned CsA-eluting IOLs exhibited reliable in vivo PCO prevention. • The drug-eluting IOLs fabricated by the simple and economical spin coating technique have a great potential in clinical translation.

Environment friendly superhydrophobic and transparent surface coating via layer-by-layer self-assembly for antifogging of optical lenses.

The fogging of the optical lenses seriously affects the life quality and safety, which is due to the gathering of the humid air into liquid droplets on the solid surface because of the temperature change. Superhydrophobic coating modification is an effective way to repel the water from surface. However, due to the specific application requirements, the transparency of optical lenses after coating modification is still the challenge for the application of such superhydrophobic coatings. In this work, a superhydrophobic and transparent surface coating was fabricated by the layer-by-layer self-assembly followed with fluorination. After poly(sodium 4-styrenesulfonate) and poly(allylamine hydrochloride) (PAH) multilayer precoating was generated on the surface, the different bilayers of SiO2 nanoparticles in different particle sizes and PAH multilayers were fabricated. The obtained polyelectrolytes-nanoparticle multilayers were fluorinated by a fluorinating agent. Such polyelectrolytes-nanoparticle multilayered coating renders obvious micro-nano composite structure, showing excellent superhydrophilicity, whereas such coating modified eyeglasses keeps excellent light transparency. The results of antifogging and defogging test also proved that the eyeglass modified with this coating had good antifogging and defogging performance. Therefore, such polyelectrolytes-nanoparticle multilayered coating with excellent superhydrophobic and transparent properties might provide a feasible approach for the practical antifogging application of optical lenses.

Enhanced PCO prevention of drug eluting IOLs via endocytosis and autophagy effects of a PAMAM dendrimer.

Drug-loaded intraocular lenses (IOLs) have received considerable attention in treating complications that arise after cataract surgery, especially posterior capsular opacification (PCO). However, for a better therapeutic effect, the drug concentration in IOLs usually needs to be increased. Herein, we developed multilayer (doxorubicin (DOX)@polyaminoamide (PAMAM) (D@P)/heparin sodium (HEP))5 modified IOLs, which efficiently enhance the inhibitory effect on PCO using the enhanced autophagy effect of a cationic PAMAM. The chemotherapeutic drug DOX was encapsulated in PAMAM to formulate cationic DOX@PAMAM nanoparticles. Subsequently, negatively charged HEP and D@P nanoparticles (NPs) were assembled on the aminated artificial IOL surface using the layer-by-layer (LBL) assembly technique. The (D@P/HEP)5 IOLs were implanted into rabbit eyes to evaluate the prevention of PCO. In vitro and in vivo research studies showed that the D@P NPs exhibited enhanced cellular uptake owing to the cell-penetrating cationic characteristics, while demonstrating enhanced autophagy. D@P NPs are more effective at the same DOX concentration when compared to free DOX. Multilayer-modified (D@P/HEP)5 IOLs can efficiently inhibit PCO after cataract surgery. This study provides a strategy for improving the therapeutic effect of antiproliferative drug DOX by using a cationic dendrimer, which, in turn, increases the level of autophagy of cells. These LBL-based multilayer IOLs have broad application prospects in the treatment of complications after cataract surgery.

Are Poly(amidoamine) Dendrimers Safe for Ocular Applications? Toxicological Evaluation in Ocular Cells and Tissues.

Purpose: The human eye is a sophisticated and sensitive sensory organ. Because of the existence of the blood-ocular barrier and corneal-scleral barrier, safe and efficient ocular drug delivery system is highly desired; yet, it remains an unsolved issue. Due to the unique structure and drug loading property, Poly(amidoamine) (PAMAM) has received much attention in the ocular drug delivery investigation. Herein, we evaluated the ocular cytotoxicity and biosafety of PAMAM dendrimers. Methods: The ocular cytotoxicity and biosafety of PAMAM dendrimers were evaluated by conducting in vitro and in vivo experiments on ocular systems. The in vitro effect of PAMAM dendrimer of different generations (G4.0, G5.0, and G6.0) and concentrations on ocular cell metabolism, apoptosis, and oxidative damage were quantitatively assessed. In vivo biosafety of PAMAM dendrimers were further investigated on intraocular tissue by ocular irritation and intravitreal injection approaches. Results: It is found that that the cytotoxicity of PAMAM was time and generation dependent. PAMAM at a concentration below 50 µg/mL had minimal impact on the ocular tissue, whereas it caused apparent damage when above 50 µg/mL in the investigated situation. Further, our in vivo results showed that higher concentration of dendrimer (100 µg/mL) was associated with functional impairment demonstrated via optical coherence tomography and electroretinogram, although macroscopic structural changes were absent in fundus and histopathological studies. Overall, a higher concentration of PAMAM, such as above 50 µg/mL, may cause ocular functional damage. Conclusion: The PAMAM at the concentrations lower than 50 µg/mL showed good biocompatibility and biosafety in human ocular cells and tissues.