Earth-abundant metal-containing photosensitizers for sustainable photodynamic inactivation in plant protection and food safety

Project Information

EcoPDI

Grant agreement ID: 101106108

DOI

10.3030/101106108

Project closed

EC signature date 9 March 2023

Start date 1 April 2023

End date 31 March 2025

Funded under

• Marie Skłodowska-Curie Actions (MSCA)

Total cost

No data

EU contribution

€ 195 914,88

Coordinated by

ECOLE NATIONALE SUPERIEURE DE CHIMIE DE PARIS
France

Periodic Reporting for period 1 - EcoPDI (Earth-abundant metal-containing photosensitizers for sustainable photodynamic inactivation in plant protection and food safety)

Reporting period: 2023-04-01 to 2025-03-31

Summary of the context and overall objectives of the project

Global food insecurity is one of the current urgent problems, since around 343 million people are now facing high levels of it, notably in Gaza and Sudan, but also in pockets of South Sudan, Haiti and Mali. In addition, agriculture is increasingly under pressure to reduce pesticide use, ensure food safety and protect the environment. To face these challenges, the EcoPDI project aimed to create a new and sustainable antimicrobial approach based on photodynamic inactivation (PDI). PDI is a light-based disinfectant method that uses a compound called photosensitizer (PS) to produce reactive oxygen species (ROS). These species can destroy harmful pathogens without being toxic to the plant.
EcoPDI designed novel PSs from earth-abundant metals such as iron, copper, cobalt, zinc, and manganese, and combined them with natural PSs to produce environmentally friendly, light-activated antimicrobial agents.
The overall objective was to develop photosensitizers that can protect crops from resistant pathogens, such as bacteria that attack tomato plants or fruit trees like pears and apples, and fungi that affect citrus fruits. The project followed a triple-impact approach: sustainable (green chemistry, sunlight activation), economic (low-cost materials), and applicable (direct use in agriculture and food safety).

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

Throughout the project, the researcher synthesized a library of metal-based PSs and characterized their chemical, photophysical, and photochemical properties. Due to early purification and water solubility challenges, modifications were made to enhance the solubility of selected candidates, including through a short-term collaboration with the biotech company Planta.at (Vienna).
Promising compounds were screened in vitro against targeted plant pathogens, leading to the identification of molecules with significant photodynamic activity under light exposure. The dose-to-light interval was further optimized, and their capability to generate reactive oxygen species was investigated using advanced analytical techniques.
Additionally, in situ trials on plants are ongoing to demonstrate that the photosensitizers are not toxic to the plant under simulated sunlight conditions. These results pave the way for real-world application and further development.
A key output of the project has been the generation of patentable compounds, which are currently being protected through a patent application. This will support future commercialization and practical uptake.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

EcoPDI advanced the field of photodynamic disinfection by introducing metal-based PSs built from sustainable, low-toxicity, and earth-abundant elements, a notable departure from conventional approaches that often rely on expensive or toxic heavy metals. Moreover, the use of naturally occurring compounds as ligands makes the final compounds safer for food and environmental applications.
The innovation lies not only in the design of these new molecules but also in their possible activation using ambient sunlight, eliminating the need for artificial light sources and reducing energy input. The potential applications span from crop protection in the field to decontamination of food surfaces during processing and storage.
For a successful future application, the next steps will include field trials, regulatory validation, scaling-up production methods, and forming partnerships with agricultural stakeholders. Support for intellectual property protection and securing funding for technology transfer will be key to ensure successful market entry.

Schematic illustration of the mode of action of the photosensitizers developed in the EcoPDI project