Seminars > June 2026
Wenesday, June 3, 2026 @ 13h30
Salle des séminaires de l'ICN - RdC du bâtiment TP Chimie (bâtiment D) - Campus Valrose
Blaise Dumat
Laboratoire CPCV UMR8228
Département de Chimie- ENS
Paris
Fluorescent pH sensors to image endo- and exocytosis
Our group is working on the development of molecular and supramolecular fluorescent probes for bioimaging. In this talk I will present two projects on the design of fluorescent pH sensors to study endo and exocytic processes. In a first project, we have designed fluorescent chemogenetic pH probes based on the HaloTag technology to monitor protein endocytosis and exocytosis (Figure 1A).1 By developing turn-on and turn-off pH probes with adequate pKa, we are able to visualize both protein secretion and internalization. The second project is the development of supramolecular probes with nanometric or micrometric size to quantitatively monitor pH during pinocytosis or phagocytosis respectively. In particular the design of micrometric lipid droplets functionalized with targeting ligands and pH probes allows triggering receptor-specific phagocytosis in macrophages and monitoring of phagosome maturation (Figure 1B).2,3
Figure 1. (A) Chemogenetic pH probes to monitor protein exocytosis by TIRF microscopy. (B) Dual-color pH-sensitive lipid
microparticles for quantitative monitoring of phagosome maturation.
References
(1) Coïs, J.; Niepon, M.-L.; Wittwer, M.; Sepasi Tehrani, H.; Bun, P.; Mallet, J.-M.; Vialou, V.; Dumat, B. A Fluorogenic Chemogenetic PH Sensor for Imaging Protein Exocytosis. ACS Sens. 2024, 9 (9), 4690–4700.
(2) Michelis, S.; Pompili, C.; Niedergang, F.; Fattaccioli, J.; Dumat, B.; Mallet, J.-M. FRET-Sensing of Multivalent Protein Binding at the Interface of Biomimetic Microparticles Functionalized with Fluorescent Glycolipids. ACS Appl. Mater. Interfaces 2024, 16 (8), 9669–9679.
(3) Michelis, S.; Uhl, H.; Niedergang, F.; Fattaccioli, J.; Dumat, B.; Mallet, J.-M. Targeted Fluorescent Lipid Microparticles for Quantitative Measurement of Phagosomal PH. bioRxiv. doi:10.1101/2025.11.20.685382.
