The investigation of molecular interactions between essential biomolecules, such as proteins, nucleic acids, or carbohydrates using microarrays, is of great interest regarding the discovery of new drug candidates, diagnostics and vaccines. In contrast to the first two compound classes, currently, there is no efficient, parallelized synthesis for glycans available, which affects the production of high-throughput glycan arrays and slows down the progress in the field of carbohydrate binding studies. With our two novel synthesis strategies, we overcome the limitations that are currently given by the leading technologies (e.g. automated glycan assembly , chemoenzymatic synthesis ) in glycan synthesis, to make a larger quantity of various glycans accessible in a faster, combinatorial, and cost-efficient manner.
On the one hand, we apply the cLIFT  technology to perform an on-chip synthesis of a large glycan library. Thereby, we deposit tiny amounts of different carbohydrate donor building blocks embedded in an inert polymer matrix from donor surfaces to a functionalized glass slide by using a laser system. Then, the actual glycosylation reaction is carried out in our home-built glycosylation chamber, where the reaction is initiated by condensing solvent and activator reagent on the carbohydrate-patterned glass slide. This method retains the resolution of the transferred spot pattern and we named it chilled vapour annealing synthesis (CVAS).  On the other hand, we applied the conventional peptide SPOT-synthesis  to glycochemistry by spotting various carbohydrate donor building blocks dissolved in a solvent on a functionalized cellulose or polypropylene membrane. Similarly, the coupling reaction also takes place in our self-made chamber using the CVAS process. After cleavage, deprotection, and purification, the obtained glycan library can be attached to a glass slide to prepare a microarray. In both methods, the key step for the success of the glycosylation is the separation of the spotting and the actual coupling step. This allows us to synthesize glycans in parallel for the very first time.
- Pardo-Vargas, A.; Delbianco, M.; Seeberger, P. H., Automated glycan assembly as an enabling technology. Curr. Opin. Chem. Biol. 2018, 46, 48-55.
- Wang, Z.; Chinoy, Z. S.; Ambre, S. G.; Peng, W.; McBride, R.; de Vries, R. P.; Glushka, J.; Paulson, J. C.; Boons, G.-J., A General Strategy for the Chemoenzymatic Synthesis of Asymmetrically Branched N-Glycans. Science 2013, 341 (6144), 379-383.
- Loeffler, F. F.; Foertsch, T. C.; Popov, R.; Mattes, D. S.; Schlageter, M.; Sedlmayr, M.; Ridder, B.; Dang, F.-X.; von Bojničić-Kninski, C.; Weber, L. K.; Fischer, A.; Greifenstein, J.; Bykovskaya, V.; Buliev, I.; Bischoff, F. R.; Hahn, L.; Meier, M. A. R.; Bräse, S.; Powell, A. K.; Balaban, T. S.; Breitling, F.; Nesterov-Mueller, A., High-flexibility combinatorial peptide synthesis with laser-based transfer of monomers in solid matrix material. Nat. Commun. 2016, 7, 11844.
- Loeffler, F. F.; Mende, M.; Eickelmann, S.; Heidepriem, J.; Tsouka, A.; Seeberger, P. H., Chilled vapour annealing synthesis for parallelized high-throughput glycan synthesis. EP18213784.4, December, 2018.
- Frank, R., The SPOT-synthesis technique: Synthetic peptide arrays on membrane supports—principles and applications. J. Immunol. Methods 2002, 267 (1), 13-26.