Noncovalent glycan immobilization

FIGURE 15.1 Noncovalent immobilization methods to construct a glycan array. 

In one of the first reports of a carbohydrate microarray, under-ivatized polysaccharides and glycoproteins were immobilized directly on nitrocellulose-coated glass slides (10). In a further demonstration of the feasibility of noncovalent immobilization of underivatized glycans, Willats et al. reported microarrays of glycoproteins, proteoglycans, and polysaccharides on oxidized black polystyrene slides (11). Modified neutral and aiuoiuc dex-tran polysaccharides have also been synthesized and printed on semicarbazide-coated glass slides (12). 

An elegant alternative approach for noncovalent interaction relies on fluorous-lluorous interactions. A glycan array of monosaccharides and disaccharides bearing anomeric fluorous tags was noncovalently immobilized on fluorous-derivatized glass slides (19, 20). The attachment method is compatible with a wide range of functional groups and has been successfully used to probe carbohydrate-protein interactions. 

Figure 2 Immobilization strategies, (a) A schematic representation of noncovalent adsorption. The lipid tail of a neo-glycolipid adheres to a hydrophobic surface via noncovalent interactions, (b) Strategies used for covalent immobilization of glycans.

General procedures to manufacture, application and management of microarrays have been described in section 14.3. Special concerns to prepare carbohydrate micioar-rays will be dealt with in this subsection. Two methods are used to immobilize glycans on the surface for the fabrication of glycochips (Feizi et al., 2003) noncovalent and covalent immobilization technologies. 

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