Despite considerable success studying glycan-binding proteins using printed glycan arrays (PGAs), unambiguous quantitation of spot intensities by fluorescent readers remains a challenge. The main obstacles are the varying spot shape and size and in-spot fluorescence distribution caused by uneven drying of the printed drops. Two methods have been suggested for solving this problem: using polymeric glycoconjugates, which makes it possible to equalize the physicochemical properties (hydrophobicity, charge, and size) of different glycans, and applying a glycan solution on a slide coated with a thin oil mask, which hinders evaporation of the drop. Both approaches yield spots with similar sizes and an even distribution of the signal across the spot and are likely to be useful for improving the prints of other classes of molecules.
Keywords: glycans; lab-on-chip; microarray; printed glycan array; spots morphology.