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Preparation and Characterization of Self-Assembled Nanoparticles of Heparin-Deoxycholic Acid Conjugates

2004; American Chemical Society; Volume: 20; Issue: 26 Linguagem: Inglês

10.1021/la048646i

1520-5827

Kyeongsoon Park, Kwangmeyung Kim, Ick Chan Kwon, Sang Kyoon Kim, Seulki Lee, Dong Yun Lee, Youngro Byun,

Dendrimers and Hyperbranched Polymers

Various deoxycholic acid (DOCA) bearing heparin (HD) amphiphilic conjugates with different degrees of substitution (DS) with DOCA were synthesized using heparin as a hydrophilic segment and DOCA as a hydrophobic segment. Structural characteristics of these HD conjugates were investigated using 1H NMR, dynamic light scattering, zeta potential, transmission electron microscopy (TEM), and fluorescence spectroscopy. HD conjugates provided monodispersed self-aggregates in water, with mean diameters decreasing with increasing DOCA DS in the range of 120-200 nm. HD aggregates were covered with negatively charged heparin shells, exhibiting xi potentials near -56 mV. The critical aggregation concentration (cac) of the HD (0.02-0.003 mg/mL) depended upon DOCA DS. TEM images demonstrated that the shape of the self-aggregates was spherical. Partition equilibrium constants, Kv, for pyrene in the self-aggregates in water indicated that increasing DS enhanced the hydrophobicity of the self-aggregate inner core. The mean aggregation number of DOCA per hydrophobic microdomain, estimated by the fluorescence quenching methods using cetylpyridinium chloride, indicated that five to nine of HD chains comprised a hydrophobic domain in the conjugates.