Self-assembled
hydrogel nanoparticles were synthesized from carboxymethylated (
CM)-curdlan, substituted with a sulfonylurea (SU) as a hydrophobic moiety for self-assembly. The degree of SU substitution was 2.4, 5.6, or 7.2 SU groups per hundred anhydroglucose units of
curdlan. The physicochemical properties of the self-assembled
hydrogel nanoparticles (DS 2.4, DS 5.6, and DS 7.2) in aqueous media were characterized by dynamic light scattering, transmission electron microscopy, and fluorescence spectroscopy. The mean diameter of all samples was less than 300 nm with a unimodal size distribution. The critical aggregation concentrations (CAC) of self-assembled
hydrogel nanoparticles in distilled water were 4.2 x 10(-2), 3.1 x 10(-2) and 1.9 x 10(-2) mg/ml for DS 2.4, 5.6 and 7.2, respectively. The loading and release of
all-trans retinoic acid (ATRA) was studied. The ATRA loading efficiencies and loading contents of
CM-curdlan/SU nanoparticles increased as the degree of SU substitution increased. The ATRA release rate was controlled by the degree of substitution and
drug-loading. For specific interaction with a hepatic
carcinoma cell line (HepG2),
CM-curdlan was additionally conjugated with
lactobionic acid (LBA;
galactose moiety) (5.5 LBA molecules per hundred
glucose units). HepG2 was strongly luminated by
ligand-receptor interactions with fluorescence-labeled LBA/
CM-curdlan/SU
hydrogel nanoparticles. The luminescence was not observed for other control cases. It is concluded that LBA/
CM-curdlan/SU
hydrogel nanoparticles are a useful
drug carrier for the treatment of
liver cancer, because of the potential immunological enhancement activities of
CM-curdlan in the body, the
ligand-receptor mediated specific interactions, and the controlled release of the anti-
cancer drug.