Dandan SU
defended her PhD thesis on Thursday 22 June 2023
“FROM (BIO)MOLECULAR RECOGNITION TO TRANSPORT:
DYNAMIC SYSTEMS FOR GENE DELIVERY, ENZYME
ACTIVATION, AND ARTIFICIAL CHANNELS“
Front of the jury composed of:
– M. Mihail BARBOIU, Directeur de Recherche, CNRS, IEM – Directeur de thèse
– M. Sébastien ULRICH, Chargé de Recherche, CNRS, IBMM – Co–directeur de thèse
– Mme. Hennie VALKENIER, Research Associate, FNRS, Université libre de Bruxelles – Rapportrice
– M. Mathieu SURIN, Maître de Recherches, FNRS, Université de Mons – Rapporteur
– M. Gilles GUICHARD, Directeur de Recherche, CNRS, Université de Bordeaux – Examinateur
– M. Michael SMIETANA, Professeur, Université de Montpellier – Examinateur
Abstract:
Dynamic constitutional chemistry has penetrated a wide range of applications over the past decades, such as materials chemistry and chemobiology. The features of dynamic assemblies contribute to the formation of constitutional (virtual) libraries from which emerge targeted compounds for biomolecular recognition. Beyond traditional molecular chemistry, supramolecular chemistry makes it possible to program molecules into the ordered functional nanostructures, and it is the participation of reversible bonds which gives access to dynamic assemblies, making it possible to observe phenomena of interest in adaptation, selection and evolution.
The object of this thesis aims to create functional dynamic systems for the recognition and transport of biomolecules. It revolves around the following three objectives: i) gene delivery, ii) activation of enzymatic catalysis and iii) transport of water and ions through artificial channels.
i) Two dynamic systems, linear dynamic covalent polymers and cross–linked dynamic constitutional networks have been designed and studied for nucleic acid recognition and transport. Peptide building blocks carrying terminal aldehyde and amine/hydrazide groups were prepared through solid phase peptide synthesis. Their covalent self–assembly process by condensation reactions bring us the candidate vectors. To better understand the mechanism and the selectivity, we have studied the complexation performance against various types of nucleic acids, and have characterized the size and structure of the formed nano–particles. Cellular transfection experiments have confirmed the potential of these vectors. Thus this study contributes to the development of a better understanding of structure– activity relationships.
ii) The construction of dynamic constitutional networks has been implemented in order to discover the potential activators of carbonic anhydrase with a rational selection of molecular modules which can contribute to the proton shuttle and/or to the changing of the microenvironment around the enzyme. A complete evaluation has been carried out by determining the association constant with the enzyme, as well as the parameters of the enzymatic catalysis by monitoring the hydrolysis of esters. Cationic
assemblies have been identified as the most efficient activators of carbonic anhydrase. These results open perspectives for the development of carbon dioxide capture in solid membrane systems.
iii) A set of bisfunctionalized urea compounds bave been prepared by the amino–isocyanate reaction to access the self–assembled water/ion channels. On the one hand, hydrophobic aliphatic chains were grafted to vary the length and the binding sites of the obtained channels. On the other hand, polar groups were selected for the formation of channel–channel or channel–water hydrogen bonds. We then have studied the selective transport capacity toward water, ions and protons. Bis–alkyl ureido imidazole channels exhibit high net water permeability but low proton conductance, meanwhile cotransport behavior with mono–alkyl ureido imidazole channels has been demonstrated. The obtained novel channels can be considered for the future development of water desalination or other environmental applica
