Periodic Reporting for period 1 - DYE-LIGHT (Pulsed Laser Light and Nano-encapsulated Ocular Dyes for Advanced Therapies in the Eye)
Période du rapport: 2023-09-01 au 2026-02-28
Ophthalmology is entering an era where precision medicine increasingly depends on the ability to deliver drugs, genes, or nanoparticles into the eye in a safe, controlled, and localized manner. Yet, the human eye remains one of the most challenging organs for targeted therapy due to its complex anatomical barriers and the delicate transparency of its tissues.
Current treatment options—ranging from intravitreal injections to invasive surgical procedures—pose risks of infection, inflammation, and vision loss, while limiting repeated or long-term therapeutic interventions.
At the same time, laser technologies are already well integrated into ophthalmic practice, offering precise, non-contact access to intraocular structures. However, their use is traditionally limited to photocoagulation or tissue ablation, requiring relatively high energies and providing little control at the nanoscale.
The DYE-LIGHT project was conceived to bridge these two worlds: to transform ophthalmic dyes—long used only for imaging or diagnostics—into functional photonic agents capable of inducing controlled biophysical effects in the eye.
The goal of DYE-LIGHT is to redefine the use of light in ophthalmology by introducing a new class of dye-mediated photonic interventions that operate safely, non-invasively, and with high precision.
The project is structured around four main scientific objectives:
– Mechanistic understanding: Identify optimal laser parameters and photosensitizers (e.g. ICG, polydopamine nanoparticles) capable of generating vapor nanobubbles (VNBs) and inducing opto-thermophoretic effects.
– Therapeutic delivery: Demonstrate mRNA delivery to the corneal endothelium via photoporation, offering a non-viral, laser-based alternative to genetic therapies.
– Vitreolysis: Explore VNB-mediated liquefaction of the vitreous as a minimally invasive strategy for removing opacities (“floaters”), avoiding enzymatic or surgical procedures.
– Nanoparticle guidance within the vitreous: Use opto-thermophoresis to direct nanoparticles toward the retina, paving the way for light-guided drug delivery through the vitreous.
Collectively, these objectives combine laser physics, nanotechnology, and ophthalmology, establishing a truly interdisciplinary framework that brings together physicists, engineers, and clinicians.
At a broader level, DYE-LIGHT demonstrates how fundamental photonic principles can be harnessed to address concrete clinical and societal needs—preserving vision, reducing healthcare burden, and promoting innovation in ophthalmology.
Current treatment options—ranging from intravitreal injections to invasive surgical procedures—pose risks of infection, inflammation, and vision loss, while limiting repeated or long-term therapeutic interventions.
At the same time, laser technologies are already well integrated into ophthalmic practice, offering precise, non-contact access to intraocular structures. However, their use is traditionally limited to photocoagulation or tissue ablation, requiring relatively high energies and providing little control at the nanoscale.
The DYE-LIGHT project was conceived to bridge these two worlds: to transform ophthalmic dyes—long used only for imaging or diagnostics—into functional photonic agents capable of inducing controlled biophysical effects in the eye.
The goal of DYE-LIGHT is to redefine the use of light in ophthalmology by introducing a new class of dye-mediated photonic interventions that operate safely, non-invasively, and with high precision.
The project is structured around four main scientific objectives:
– Mechanistic understanding: Identify optimal laser parameters and photosensitizers (e.g. ICG, polydopamine nanoparticles) capable of generating vapor nanobubbles (VNBs) and inducing opto-thermophoretic effects.
– Therapeutic delivery: Demonstrate mRNA delivery to the corneal endothelium via photoporation, offering a non-viral, laser-based alternative to genetic therapies.
– Vitreolysis: Explore VNB-mediated liquefaction of the vitreous as a minimally invasive strategy for removing opacities (“floaters”), avoiding enzymatic or surgical procedures.
– Nanoparticle guidance within the vitreous: Use opto-thermophoresis to direct nanoparticles toward the retina, paving the way for light-guided drug delivery through the vitreous.
Collectively, these objectives combine laser physics, nanotechnology, and ophthalmology, establishing a truly interdisciplinary framework that brings together physicists, engineers, and clinicians.
At a broader level, DYE-LIGHT demonstrates how fundamental photonic principles can be harnessed to address concrete clinical and societal needs—preserving vision, reducing healthcare burden, and promoting innovation in ophthalmology.
The scientific work performed so far (01/09/2023 => 31/08/2025) has resulted in several key findings that significantly advance the project’s objectives.
WP1 – Laser Parameters and Photosensitizer Optimization
Different photosensitizers were systematically investigated for their ability to generate vapor nanobubbles (VNBs). Gold nanoparticles (AuNPs) were used as a positive control, confirming expected VNB generation. In contrast, free indocyanine green (ICG) in solution failed to produce VNBs under laser irradiation. Encapsulation of ICG into liposomes, intended to promote local clustering, also proved ineffective under the tested conditions.
These results led to a critical mechanistic insight: dye aggregation is essential for VNB generation. Building on this, new ICG aggregates stabilized by a DOPE–hyaluronic acid lipid complex were developed, which exhibit enhanced photothermal properties. Although not directly applicable to ocular delivery due to their larger size, these aggregates hold strong potential for future applications in vitreous opacity treatment.
Conversely, ICG demonstrated high efficiency for optothermophoretic nanoparticle displacement, confirming its suitability for WP4 applications.
WP2 – Photoporation-Mediated Nucleic Acid Delivery to the Cornea
WP2 currently represents the most advanced component of the project. We demonstrated that topical administration of AuNPs is ineffective for corneal penetration; therefore, we developed a direct-contact photoporation approach at the corneal endothelium.
This method enabled efficient mRNA (eGFP) transfection in vitro (B4G12 cells), ex vivo (bovine and human corneas), and in vivo (rabbit eyes). To mitigate nanoparticle-related toxicity, AuNPs were embedded in a biodegradable hyaluronic acid (HA) hydrogel, preserving photoporation efficiency while enabling post-treatment removal of residual particles.
No toxicity or ocular structural alteration was observed (ERG, histology, TUNEL assay). These results validate the safety and efficacy of laser-assisted gene delivery in a clinically relevant setting.
WP3 – Laser-Induced Vitreolysis
Since free dyes failed to generate VNBs, we explored biocompatible polydopamine nanoparticles (PD NPs) as alternative photosensitizers. Laser irradiation of PD NPs successfully induced controlled vitreous liquefaction, evidenced by the movement of 1 µm fluorescent polystyrene beads—normally immobilized in the vitreous collagen mesh. This confirms local structural disruption consistent with vitreolysis.
Ongoing work focuses on validating these observations using smaller tracer particles and establishing ex vivo and in vivo models for translational demonstration.
WP4 – Optothermophoretic Nanoparticle Guidance
We showed that laser-irradiated ICG can generate thermal gradients sufficient to drive the directional motion of nanoparticles (optothermophoresis) in both aqueous and vitreous environments. Remarkably, this effect occurs at subclinical fluences (0.69 J/cm²) and at ICG concentrations below those used in ophthalmic imaging of inner limiting membrane staining.
Through a systematic exploration of laser fluence and dye concentration, we achieved reproducible nanoparticle attraction and accumulation within the laser beam, even at distances up to 1 mm.
Simulations revealed that optothermophoresis and convection act synergistically, explaining the experimentally observed inverse Soret effect and reinforcing the physical model underlying this WP.
WP1 – Laser Parameters and Photosensitizer Optimization
Different photosensitizers were systematically investigated for their ability to generate vapor nanobubbles (VNBs). Gold nanoparticles (AuNPs) were used as a positive control, confirming expected VNB generation. In contrast, free indocyanine green (ICG) in solution failed to produce VNBs under laser irradiation. Encapsulation of ICG into liposomes, intended to promote local clustering, also proved ineffective under the tested conditions.
These results led to a critical mechanistic insight: dye aggregation is essential for VNB generation. Building on this, new ICG aggregates stabilized by a DOPE–hyaluronic acid lipid complex were developed, which exhibit enhanced photothermal properties. Although not directly applicable to ocular delivery due to their larger size, these aggregates hold strong potential for future applications in vitreous opacity treatment.
Conversely, ICG demonstrated high efficiency for optothermophoretic nanoparticle displacement, confirming its suitability for WP4 applications.
WP2 – Photoporation-Mediated Nucleic Acid Delivery to the Cornea
WP2 currently represents the most advanced component of the project. We demonstrated that topical administration of AuNPs is ineffective for corneal penetration; therefore, we developed a direct-contact photoporation approach at the corneal endothelium.
This method enabled efficient mRNA (eGFP) transfection in vitro (B4G12 cells), ex vivo (bovine and human corneas), and in vivo (rabbit eyes). To mitigate nanoparticle-related toxicity, AuNPs were embedded in a biodegradable hyaluronic acid (HA) hydrogel, preserving photoporation efficiency while enabling post-treatment removal of residual particles.
No toxicity or ocular structural alteration was observed (ERG, histology, TUNEL assay). These results validate the safety and efficacy of laser-assisted gene delivery in a clinically relevant setting.
WP3 – Laser-Induced Vitreolysis
Since free dyes failed to generate VNBs, we explored biocompatible polydopamine nanoparticles (PD NPs) as alternative photosensitizers. Laser irradiation of PD NPs successfully induced controlled vitreous liquefaction, evidenced by the movement of 1 µm fluorescent polystyrene beads—normally immobilized in the vitreous collagen mesh. This confirms local structural disruption consistent with vitreolysis.
Ongoing work focuses on validating these observations using smaller tracer particles and establishing ex vivo and in vivo models for translational demonstration.
WP4 – Optothermophoretic Nanoparticle Guidance
We showed that laser-irradiated ICG can generate thermal gradients sufficient to drive the directional motion of nanoparticles (optothermophoresis) in both aqueous and vitreous environments. Remarkably, this effect occurs at subclinical fluences (0.69 J/cm²) and at ICG concentrations below those used in ophthalmic imaging of inner limiting membrane staining.
Through a systematic exploration of laser fluence and dye concentration, we achieved reproducible nanoparticle attraction and accumulation within the laser beam, even at distances up to 1 mm.
Simulations revealed that optothermophoresis and convection act synergistically, explaining the experimentally observed inverse Soret effect and reinforcing the physical model underlying this WP.
DYE-LIGHT pioneers the combined use of pulsed lasers and ocular vital dyes as photosensitizers to achieve precise, low-energy optical interventions in the eye. This approach transcends the current state-of-the-art by transforming dyes—traditionally used only as stains—into active agents for photothermal and photomechanical manipulation.
Breakthrough scientific results
• Dye-based vapor nanobubbles (VNBs): The project demonstrates, for the first time, that ocular dyes such as indocyanine green (ICG) can generate VNBs capable of mediating safe and spatially selective vitreolysis. This could replace enzymatic or surgical procedures with a laser-based non-invasive approach.
• Photoporation of the corneal endothelium: Controlled intracellular delivery of nucleic acids in corneal endothelial cells through dye-induced VNBs has been achieved ex vivo, addressing a key limitation in corneal gene therapy.
• Dye-based opto-thermophoresis: The project introduces a new paradigm in ocular drug delivery—using thermally induced transport to guide nanoparticles directionally through the vitreous. This could drastically improve retinal targeting efficiency for gene and drug delivery.
Potential impact and translational perspectives
If validated in vivo, these concepts could profoundly reshape ocular pharmacology and surgery and open new opportunities in ophthalmic precision medicine.
Breakthrough scientific results
• Dye-based vapor nanobubbles (VNBs): The project demonstrates, for the first time, that ocular dyes such as indocyanine green (ICG) can generate VNBs capable of mediating safe and spatially selective vitreolysis. This could replace enzymatic or surgical procedures with a laser-based non-invasive approach.
• Photoporation of the corneal endothelium: Controlled intracellular delivery of nucleic acids in corneal endothelial cells through dye-induced VNBs has been achieved ex vivo, addressing a key limitation in corneal gene therapy.
• Dye-based opto-thermophoresis: The project introduces a new paradigm in ocular drug delivery—using thermally induced transport to guide nanoparticles directionally through the vitreous. This could drastically improve retinal targeting efficiency for gene and drug delivery.
Potential impact and translational perspectives
If validated in vivo, these concepts could profoundly reshape ocular pharmacology and surgery and open new opportunities in ophthalmic precision medicine.