Kwon, S Park, JH Chung, H Kwon, IC Jeong, SY Kim, IS 2024-01-21T08:02:35Z 2024-01-21T08:02:35Z 2021-09-03 2003-11-25 0743-7463 https://pubs.kist.re.kr/handle/201004/138072 The self-aggregation behavior and microscopic characteristics of hydrophobically modified glycol chitosans (HGCs), prepared by covalent attachment of 5beta-cholanic acid to glycol chitosan, were investigated by using H-1 NMR, dynamic light scattering, fluorescence spectroscopy, and transmission electron microscopy (TEM). The HGCs formed self-aggregates in an aqueous phase by intra- or intermolecular association between hydrophobic 5beta-cholanic acids attached to glycol chitosan. The critical aggregation concentrations (cacs) of the HGCs were dependent on the degree of substitution (DS) of 5beta-cholanic acid and were significantly lower than those of low molecular weight surfactants. The mean diameters of the self-aggregates decreased with the increase in the DS of 5beta-cholanic acid because of the formation of compact hydrophobic inner cores. The TEM images demonstrated that the shape of the self-aggregates, on the basis of the HGCs, is spherical. The partition equilibrium constants (K-v) of pyrene, measured in the self-aggregate solutions of the HGCs, indicated that the increase in the DS enhances the hydrophobicity of inner core of self-aggregates. The aggregation number of 5beta-cholanic acid per one hydrophobic microdomain, estimated by the fluorescence quenching method using cetylpyridinium chloride, increased with increasing the DS, which suggested that several HGC chains were needed to form one hydrophobic domain. English AMER CHEMICAL SOC POLYION COMPLEX MICELLES BLOCK-COPOLYMERS SODIUM TAURODEOXYCHOLATE POLY(ETHYLENE GLYCOL) HYDROGEL NANOPARTICLE AGGREGATION NUMBER BILE-SALT IN-VITRO DELIVERY WATER Physicochemical characteristics of self-assembled nanoparticles based on glycol chitosan bearing 5 beta-cholanic acid Article 10.1021/la0350608 1 LANGMUIR, v.19, no.24, pp.10188 - 10193 LANGMUIR 19 24 10188 10193 scie scopus 000186694500031 2-s2.0-0344082860 Chemistry, Multidisciplinary Chemistry, Physical Materials Science, Multidisciplinary Chemistry Materials Science Article POLYION COMPLEX MICELLES BLOCK-COPOLYMERS SODIUM TAURODEOXYCHOLATE POLY(ETHYLENE GLYCOL) HYDROGEL NANOPARTICLE AGGREGATION NUMBER BILE-SALT IN-VITRO DELIVERY WATER chitosan