Viscometric affinity assay

The spot test described herein is based on the Viscometric Affinity Assay (VAA) described earlier [/, 2]. The principle of the VAA is based on the fact that the mixture of the glucose-specific lectin Concanavalin A (ConA, [3,4]) with a highly concentrated dispersion of 1,000 kDa dextran (wt 1-10%) yields a tremendous rise of the resulting viscosity (up to 20 times). Such viscous dispersions can adopt gel-like properties as discussed in detail by Ehwald et al. [5]. This viscous behavior is due to extensive intermolecular affinity crosslinking of dextran molecules by ConA (see Figure la). 

Figure 1. Schematics of mechanism of the Viscometric Affinity Assay (VAA).

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