Valentine Guilbaud

@article{VANUCCIBACQUE2025125932,
    title = {Tricarbonylrhenium(I) complexes with aggregation-induced phosphorescence emission (AIPE) properties: Application to the selective detection of heparin and its main contaminant},
    journal = {Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy},
    pages = {125932},
    year = {2025},
    issn = {1386-1425},
    doi = {https://doi.org/10.1016/j.saa.2025.125932},
    url = {https://www.sciencedirect.com/science/article/pii/S1386142525002380},
    author = {Corinne Vanucci-Bacqué and Valentine Guilbaud and Maëlle Deleuzière and Charles-Louis Serpentini and Florence Bedos-Belval and Eric Benoist and Suzanne Fery-Forgues},
}        
                        

Phosphorescent tricarbonylrhenium(I) complexes that are more emissive in the aggregate state than in solution could be very valuable probes for biological analyses, but their development is delicate. The present work focuses on the synthesis and spectroscopic study of three new complexes that differ by the nature of their positively charged substituent. The dissolved complexes were very weakly emissive. Due to electrostatic interaction and aggregation, they showed a strong aggregation-induced phosphorescence enhancement (AIPE) effect in the presence of heparin, a polyanionic macromolecule of biological interest, and a weaker effect in the presence of chondroitin sulfate, which contains fewer negative charges. The magnitude of the AIPE effect depended on the nature of the complex. However, it was weaker than expected from the behavior of the parent neutral complex studied in a conventional acetonitrile/water system, which highlights the challenge of accurately predicting solid-state emission properties for this class of molecules. This work introduces rhenium(I) complexes in the field of AIPE-active probes for the detection of polyanionic biomolecules.

@article{GUILBAUD2024115600,
    title = {Development of photoactivatable CO-releasing tricarbonylrhenium(I) complexes and their integration into cellulose nanocrystals in view of antibacterial activity},
    journal = {Journal of Photochemistry and Photobiology A: Chemistry},
    volume = {453},
    pages = {115600},
    year = {2024},
    issn = {1010-6030},
    doi = {https://doi.org/10.1016/j.jphotochem.2024.115600},
    url = {https://www.sciencedirect.com/science/article/pii/S1010603024001448},
    author = {Valentine Guilbaud and Marie Goizet and Nadine Leygue and Alexandre Poirot and Sonia Mallet-Ladeira and Charles-Louis Serpentini and Tan-Sothéa Ouk and Gauthier M.A. {Ndong Ntoutoume} and Vincent Sol and Eric Benoist and Suzanne Fery-Forgues},
}
                        

Infections caused by antibiotic-resistant bacteria represent a major public health problem, and efforts continue to be made to seek new ways of addressing this issue. Photoactivatable carbon monoxide (CO)-releasing molecules (photoCORMs) could be an alternative solution to conventional antibiotics, but their mechanism of action is complex and still badly known. In the present work, a tricarbonylrhenium(I) complex (Re-Phe(TPP)) was developed, as well as a more hydrophobic analogue substituted by an adamantyl moiety (Re-Ada(TPP)). When irradiated in the near UV, these molecules generate rapidly one molecule of CO, as well as small amounts of singlet oxygen (1O2). Their decarbonylated photoproducts D-Re-Phe(TPP) and D-Re-Ada(TPP) generate only 1O2, on a prolonged period of time. All these complexes were immobilized on a biocompatible cellulose nanocrystal (CNC) matrix, so that only the diffusive species (CO and 1O2) may be the active ones. Finally, the bactericidal activity of all these systems was evaluated on two bacteria strains, causative of the main wound infections. No compound was active against Pseudomonas aeruginosa. Free Re-Phe(TPP) appeared to be a very good antibacterial agent in the dark against Staphylococcus aureus, although the same molecule adsorbed on the CNC material was ineffective, so that its activity was mainly attributed to direct biological effect. The adamantyl derivative Re-Ada(TPP) was more active in the presence of light than in the dark, possibly due to the contribution of CO and 1O2. In contrast, the decarbonylated photoproduct D-Re-Phe(TPP) only showed moderate activity, suggesting that the production of 1O2 is not enough to induce a significant bactericidal effect. This work allows to identify the limits of Re(I) photoCORMs and corresponding nanomaterials, which are still little used in the fight against bacteria, and it provides good indications on how to improve their design.