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Langmuir. 2004 Dec 21;20(26):11726-31.

Preparation and characterization of self-assembled nanoparticles of heparin-deoxycholic acid conjugates.

Author information

1
Center for Cell and Macromolecular Therapy, Department of Materials Science and Engineering, Gwangju Institute of Science and Technology, 1 Oryong-dong Puk-gu Gwangju 500-712, Korea.

Abstract

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.

PMID:
15595804
DOI:
10.1021/la048646i
[Indexed for MEDLINE]

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