Supramolecular assembly and chirality of synthetic carbohydrate materials

07 septembre 2020 par Super Administrateur [TheChamp-Sharing]
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.

Abstract:
« 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