Photodynamic Therapy Applications in Chronic Diseases

Photodynamic Therapy (PDT) harnesses the interaction of a photosensitiser, light and molecular oxygen to generate reactive oxygen species that selectively ablate or modulate target tissues. Originally established in oncology, its precision and minimal invasiveness have spurred exploration for a range of chronic conditions. In chronic inflammatory and vascular diseases, PDT modulates pathological cell populations and remodels aberrant vasculature. In chronic infections, antimicrobial PDT (aPDT) offers a strategy to overcome antibiotic resistance through broad‐spectrum pathogen inactivation. Applications extend to autoimmune disorders, where controlled photostimulation can attenuate synovial hyperplasia and inflammatory cascades. Moreover, nanocarrier‐enabled photosensitisers improve tissue targeting and depth of light penetration, addressing limitations in accessibility of deep‐seated lesions. Recent advances in photosensitiser chemistry, such as activatable agents and organelle‐targeted molecules, have further refined selectivity and reduced off‐target effects. Clinical translation has begun, with early‐phase trials demonstrating safety and efficacy in dermatological, ophthalmological and cardiovascular contexts. The global significance of PDT lies in its versatility, potential for repeated administration without cumulative toxicity and compatibility with existing therapeutic regimens. Continued interdisciplinary research, integrating biomaterials, optical engineering and clinical science, is essential to unlock the full spectrum of PDT applications in chronic disease management.

Research from Nature Portfolio

Recent studies have demonstrated the therapeutic potential of second‐generation photosensitisers in ocular chronic disease. One investigation into targeted chlorin conjugates revealed that subretinal administration followed by near‐infrared illumination substantially reduced neovascular proliferation in a preclinical model of diabetic macular oedema, while preserving adjacent neuronal tissue integrity. Another study employed photochemical internalisation to enhance delivery of fibrotic‐targeting agents in experimental liver cirrhosis. This approach achieved selective disruption of activated stellate cells and reduced collagen deposition, signalling a promising avenue for non‐invasive treatment of chronic hepatic fibrosis.

Photodynamic Therapy Applications in Chronic Diseases publication trend

The graph below shows the total number of articles in photodynamic therapy applications in chronic diseases across all publications each year (not limited to Nature Index journals).

Technical terms

Photosensitiser: A molecule that, upon light activation, transfers energy to oxygen to produce reactive oxygen species.

Reactive Oxygen Species (ROS): Chemically reactive molecules derived from oxygen that induce cellular damage.

Photochemical Internalisation: A technique that uses light‐activated compounds to release therapeutic agents from endolysosomal compartments.

Antimicrobial Photodynamic Therapy (aPDT): The application of PDT principles to inactivate microbial pathogens.

Nanocarrier: A nanoscale vehicle designed to deliver drugs, enhancing stability and targeting.

Neovascularisation: The formation of new blood vessels, often associated with chronic inflammation or disease.

References

1. In Vitro Antimicrobial Photodynamic Therapy for Pseudomonas aeruginosa (P. aeruginosa) and methicillin-resistant Staphylococcus aureus (MRSA) Inhibition Using a Green Light Source. Pharmaceutics (2024).
2. Photodynamic Therapy Review: Principles, Photosensitizers, Applications, and Future Directions. Pharmaceutics (2021).
3. Photosensitizers Used in the Photodynamic Therapy of Rheumatoid Arthritis. International Journal of Molecular Sciences (2019).
4. Non-Oncologic Applications of Nanomedicine-Based Photo-Therapy. Biomedicines (2021).
5. Photosensitization of experimental atheromas by porphyrins. Journal of the American College of Cardiology (1987).