Facile one-step synthesis of <i>β</i> -cyclodextrin-substituted alginate with host–guest recognition ability via aqueous condensation reaction

Abstract A facile one-step synthesis of β-cyclodextrin-substituted alginate (Alg-β-CD) was achieved through a condensation reaction between sodium alginate (AlgNa) and 6-amino-6-deoxy-β-cyclodextrin (NH₂-β-CD) in H2O. NMR and IR analyses confirmed the covalent incorporation of β-CD units. The hydrogel beads prepared from Alg-β-CD exhibited enhanced inclusion of methyl orange (MO) compared with those from AlgNa, showing higher initial uptake and 38% retention after 360 min. Pseudo-second-order kinetic analysis revealed slower MO release from Alg-β-CD, demonstrating a simple and sustainable route to functional Alg-based materials with guest-recognition capability.