This project focuses on synthetic functional systems that are relevant for the life sciences.  The general objective is to create fluorescent membrane probes that change color like lobsters during cooking, that is by a combined planarization and polarization of twisted push-pull chromophores.  The same principle accounts for color vision and, somehow, also for plant pigmentation, but it is surprisingly underexplored in the context of fluorescent probes.  The idea was originally tested with twisted push-pull oligothiophenes.  It was found that planarizable push-pull probes are of interest to detect the nature of lipid bilayer membranes, even with the naked eye.

Current projects focus on the design, synthesis and evaluation of planarizable push-pull probes with improved properties (increased contact areas for improved mechanosensitivity, better quantum yields, and so on) and on the detection of membrane tension (biologically relevant but underexplored), heterogeneity and possibly also potentials (for neural imaging).

Methods:  This project builds on quite significant multistep organic synthesis (retrosynthetic analysis, modern synthetic methods (organometallics, µW, etc), purification techniques (TLC, flash, LC-MS, HPLC, RP-HPLC, SEC, etc), compound characterization (NMR, ESI, MALDI, HRMS, UV, IR, CD, mp, optical rotation, etc)).  Probe characterization involves spectroscopic methods (absorption, fluorescence, quantum yields, lifetimes, etc) as well as spectroscopic studies in vesicles (LUVs (polarized, stressed, mixed, depth quenching), GUVs (imaging, aspiration, optical tweezers), in Langmuir monolayers, supported bilayers on bendable surfaces, and in cells.

Collaborations:  This is an NCCR project,realized in close collaboration with other members, including also NCCR group meetings, lectures, workshops, retreats, etc (Aurelien Roux, Andreas Zumbuehl).  Interdisciplinary (post)doctoral studies in both chemistry and biology groups are possible.

Recent reference:  Angew. Chem. Int. Ed. 2012, 51, 12736.