Two different amino acid-polyrotaxane (AA-PR) conjugates were synthesized and examined using two types of amino acids, i.e., alanine (Ala) and phenylalanine (Phe), and a PR containing poly(ethylene glycol) and alpha-cyclodextrin (CD) axes via the activation of the carboxyl groups in the AAs using 1,1'-carbonyldiimidazole and subsequent esterification with the hydroxyl groups in the CDs. The degree of substitution (DS) of the obtained conjugates was determined using H-1 NMR spectroscopy, titration after deprotection and ultraviolet absorbance analyses (in the case of the Phe-PR conjugates). The DS values obtained using these were in good agreement, indicating that the DS could be controlled by varying the reaction temperature, reaction time, and [AA]/[-OH] stoichiometric ratio, the last of which provided the widest DS control. The Boc-Phe-PR conjugate exhibited solubility behavior dependent on the solvent and temperature, i.e., an upper critical solution temperature in methanol and a lower critical solution temperature in ethanol. Various AA-PR slide-ring gels were prepared by crosslinking the deprotected cationic conjugates using hexamethylene diisocyanate. The degree of swelling was highest at pH = 4.64 and much lower at higher and lower pH. The low swelling of the gels at higher and lower pH is attributed to deprotonation of the primary amino groups in the gels and hydrolytic dissociation of the ester linkages between the AAs and PRs, respectively. (C) 2015 Elsevier Ltd. All rights reserved.