Carbohydrates are found on cell-surfaces of most organisms and viruses, on proteins, and even on bioactive small molecules (eg. macrolide antibiotics). Complex carbohydrate- (glycan-) mediated interactions play a crucial role in biology and medicine, influencing cell signalling, immune responses, and disease pathways. Hence, there is great potential to use glycans as targets for biosensing or diagnostics. However, their high hydrophilicity attenuates binding affinity. Moreover, certain glycan motifs are recognised by biologically distinct protein partners. In this project, we wish to address this affinity/selectivity problem by exchanging alcohol groups to fluorine. This leads to the modification (and introduction) of a range of different interactions which, depending on the particular binding site of a protein partner, will be attractive or repulsive. Using the LewisX trisaccharide, which is known to interact with a wide variety of proteins and is involved in multiple biochemical processes, as model, a chemo-enzymatic synthesis of a library of analogues only differing in its fluorination pattern is proposed, and which includes unprecedented polyfluorination motifs. These will be submitted to extensive microarray-based screening to obtain fingerprint binding profiles in order to identify their selectivities in binding. The ultimate goal is to investigate whether such novel structures are promising for diagnostic purposes.