Glycosaminoglycans (GAGs), such as chondroitin sulfate, heparin and hyaluronic acid, are abundant within the body, where they are present predominantly on the cell surface and within the extracellular matrix (ECM). They play vital physiological roles and are altered in many pathological conditions. They are linear polysaccharides composed of repeating disaccharide units of uronic acids and amino-sugar residues. The large structural variation among GAGs arises from their degree of sulfation (except for hyaluronic acid), acetylation and the identity of the constituent sugar residues. GAG structural analysis can be very complicated, time-consuming and requires a high level of expertise. Contamination of heparin with other GAG residues, later found to be over-sulfated chondroitin sulfate (OSCS), led to a worldwide crisis in 2008. The current methods for the detection of contaminants in heparin are nuclear magnetic resonance (NMR), capillary electrophoresis (CE) and strong anion exchange (SAX) high-performance liquid chromatography (HPLC), as recommended by the US Food and Drug Administration (FDA). For a more high-thoughput approach, we developed a method of fluorescently labelling polysaccharides and profiling them on a custom lectin microarray. Polysaccharides of different structures, including gellan and dextran were found to generate different profiles and the polysaccharide-lectin interactions were inhibitable with unlabelled polysaccharide. A panel of chondroitin sulfate polysaccharides, heparin and heparan sulfate from different species were profiled on the lectin microarrays and were also found to generate unique profiles. Thus, lectin microarrays, combined with this convenient polysaccharide labelling method, potentially provide a high throughput option to differentiate closely-related, structurally complex polysaccharides and to detect contaminants of heparin preparations.
