Globular carbohydrate macromolecule "sugar balls" IV. Synthesis of dendritic nanocapsules with molecular recognition sites on periphery

8-Anilino-1-naphthalenesulfonic acid sodium salt (ANS)-encapsulated [O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-L-serine]-persubstituted poly(amido amine) (PAMAM) dendrimers (G=6.0, 7.0, and 8.0) and ANS-encapsulated [O-(beta-D-galactopyranosyl)-L-serine]-persubstituted PAMAM dendrimers (G=7.0 and 8.0) were synthesized by polymer reaction between PAMAM dendrimers and glycoNCAs (i.e., O-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-beta-D- glucopyranosyl)-L-serine N-carboxyanhydride (NCA) and O-[tetra-O-acelyl-beta-D-galactopyranosyl)-L-serine NCA) in the presence of ANS in chloroform, followed by deacetylation with hydrazine monohydrate in methanol. Number of ANS molecules per the mono(glycopeptide)-type sugar ball capsule was determined by quantitative UV analysis of the hydrolysis product of the capsule under a basic condition. The results suggested that the encapsulation efficiency depended on the surface density of sugar residues. UV and fluorescent analyses and gel filtration chromatography of the capsule indicated the existence of ANS in a relatively hollow internal cavity of the mono(glycopeptide)-type sugar ball capsule. An inhibition test of hemagglutinating activity of wheat germ agglutinin (WGA) lectin demonstrated that the capsule has a highly specific molecular recognition ability owing to the sugar residues.