UPR 5301

Supramolecular assembly and chirality of synthetic carbohydrate materials

We have just published the results of our international collaboration with MPI-Potsdam (Germany) in Angewandte Chemie International Edition. In this work, we built a model carbohydrate material system based on synthetic gluycose disaccahrdes. Microcrystal electron diffraction (microED) analysis revealed that the synthetic disaccharides formed highly crystalline helical fiber. The chirality of the assembled helical fibers can be tunable by changing the enantiomeric structure of the disaccharides, underlining the potential of designer carbohydrate materials for nanotechnology applications.

« Hierarchical carbohydrate architectures serve multiple roles in Nature. Hardly any correlations between the carbohydrate chemical structures and the material properties are available due to the lack of standards and suitable analytic techniques. Therefore, designer carbohydrate materials remain highly unexplored, as compared to peptides and nucleic acids. Here, a synthetic D-glucose disaccharide, DD, is chosen as model to explore carbohydrate materials. Microcrystal electron diffraction (MicroED), optimized for oligosaccharides, revealed that DD assemble into highly crystalline left-handed helical fibers. The supramolecular architecture was correlated to the local crystal organization, allowing for the design of the enantiomeric right-handed fibers, based on the L-glucose disaccharide, LL, or flat lamellas, based on the racemic mixture. Tunable morphologies and mechanical properties suggest the potential of carbohydrate materials for nanotechnology applications. Carbohydrates, the most abundant organic material on Earth, are also capable of forming hierarchical architectures. Still, their molecular level description remains limited due to difficult access to pure materials and a lack of suitable analytical techniques.

The potential of carbohydrate materials remains thus highly underexploited. The synthesis of well-defined polysaccharide sequences is labor intensive. Moreover, the intrinsic flexibility of short oligosaccharides has hampered their use for the formation of supramolecular structures. As a consequence, carbohydrates have found limited applications in nanotechnology, with the only exception being nanocellulose. Still, nanocellulose is often directly extracted from natural sources (top-down approach), limiting molecular design opportunities and detailed structurefunction correlations. »

The publication is availaible over here: https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202008153