The inclusion ability on alginate, a hydrogel forming polysaccharide, has been introduced by covalently linking alpha-cyclodextrin (alpha-CD). The secondary hydroxyl groups of sodium alginate were activated with cyanogen bromide and subsequently reacted with 6-amino-alpha-CD. The degree of substitution (DS) of the resulting alpha-CD linked alginate was 0.05-1.58 depending on reaction condition and the ratio of 6-amino-alpha-CD and alginate. Using p-nitrophenol as a model compound in UV-vis and circular dichroism spectroscopic examination, the modified polysaccharide showed an ability to form a host-guest complex. Furthermore, the alpha-CD linked alginate found to be provided the spherical beads by treating with a calcium chloride solution. (c) 2005 Elsevier Ltd. All rights reserved.