AGGREGATION BEHAVIOR AND INTERACTION WITH HUMAN SERUM-ALBUMIN OF 2-OXAZOLINE BLOCK-COPOLYMERS IN AQUEOUS-SOLUTIONS

The structure of the aggregates of block copolymers containing poly[(N -acetylimino)ethylene] as hydrophilic block and poly[(N-acylimino)ethy lene]s as hydrophobic block was studied by size exclusion chromatograp hy, dynamic light scattering, and transmission electron microscopy. Th e morphology of the aggregates, consisting of spherical and rod-like m icelles, depends on the chemical structure of the block copolymers. Th e adsorption behavior of human serum albumin (HSA) onto each polymer a ggregate was studied by size exclusion chromatography. The maximum amo unt of HSA bound onto the polymer aggregates depends on the morphology of the polymer aggregates. Adsorption isotherms of HSA for each polym er aggregate are in good agreement with a Langmuir adsorption isotherm . The amount of HSA adsorbed onto the aggregates is not influenced by the fatty acid content in HSA. The electrophoretic mobility of the agg regates without HSA is close to zero, and the negative mobility increa ses when HSA is incorporated into the aggregates. The experimental res ults suggest that adsorption of HSA to the aggregates occurs mainly at the surface or at the hydrophilic shell of the polymer aggregates, no t at the hydrophobic core of the polymer micelles.