Description of the thesis topic

Photodynamic therapy (PDT) is based on the interaction between a photosensitizer, light and ground-state oxygen (3O2), producing highly reactive oxygen species such as the cytotoxic singlet oxygen (1O2), which can be used against cancer and microbial pathogens. Currently, PDT faces two major limitations: the control of oxygen delivery and the limited penetration of light into tissues. This PhD thesis is part of a collaborative ANR project to develop new porous coordination polymers, or Metal Organic Frameworks (MOFs), capable of decoupling the light irradiation and singlet oxygen release stages. MOFs are built from inorganic building blocks connected by polytopic organic ligands to define cavities of various sizes and shapes. The aim here is to produce porous compounds combining two types of organic ligands, arenes and porphyrins, in a single structure. Porphyrins are excellent photosensitizers capable of generating 1O2, while arenes are aromatic molecules capable of trapping this 1O2 in their structure through the reversible formation of endoperoxide (EPO). Thus, EPO-containing MOFs can be generated by illumination at the optimum porphyrin excitation wavelength and stored at low temperature until they are used to controllably release singlet oxygen into the desired environment by heating.
The research work will include:
- Synthesis of suitable organic ligands (porphyrin and anthracene derivatives).
- Study of the reactivity of these ligands with various metal cations, especially using high-throughput tools.
- characterization of the resulting solids using standard techniques of the field, particularly X-ray diffraction (single crystal/powder), UV-visible and infrared spectroscopies, thermogravimetric analysis, gas adsorption, etc.
The properties of singlet oxygen generation and release will be assessed through external collaborations.
The candidate should hold a Master's degree in chemistry, physical chemistry or materials science. As this project lies at the interface between molecular chemistry and materials chemistry, an interest in both fields is expected, as well as in characterization techniques, particularly X-ray diffraction.

Work Context

This PhD project will be carried out jointly in two Nantes laboratories, CEISAM (Interdisciplinary Chemistry: Synthesis, Analysis, Modelling) and IMN (Institute of Materials Nantes Jean Rouxel), two joint CNRS-Nantes University research units (UMR). It will developed as part of the ANR MOFSONG collaborative project, involving 5 academic laboratories (LMI Lyon, CRMN Lyon, IMN Nantes, CEISAM Nantes and LRGP Nancy).

The position is located in a sector under the protection of scientific and technical potential (PPST), and therefore requires, in accordance with the regulations, that your arrival is authorized by the competent authority of the MESR.

Constraints and risks

The PhD student will be based at IMN and CEISAM (located 100 m from each other), but shorts stays in the partner's laboratories are also planned. The IMN and CEISAM laboratories are governed by internal regulations.