Compositions are disclosed that include a support having on a surface thereof at least an inner polysaccharide layer and an outer polysaccharide layer. The outer polysaccharide layer has pendant moieties each comprising a terminal amine functionality. The point of linkage of the pendant moiety to the outer polysaccharide layer does not comprise an amide bond. The composition may be employed in a method of conjugating a member of a specific binding pair to a particle. The method comprises reacting the terminal amine functionality of the composition with the member of the specific binding pair, which comprises an amine-reactive functionality.
