Hydrodynamic properties of carbohydrate-coated dendrimers

The hydrodynamic properties of poly(propylene imine) dendrimers, modified w ith outer-surface beta-thiolactosyl residues ("lactodendrimers") of generat ion number 1-5, have been investigated by velocity sedimentation, translati onal diffusion, and viscosity measurements in 0.165% NaCl aqueous solution. It has been demonstrated that apparent molecular weights (from the Svedber g equation) M-sD of synthetic lactodendrimers, determined by sedimentation and diffusion experiments, are consistent with complete functionalization o f initial poly(propylene imine) dendrimers with sugar residues. The values of M-sD range from 1900 to 45000 Da for generation numbers 1-5. Correspondi ng hydrodynamic (''equivalent Stokes'') radii range from similar to 10 to s imilar to 37 Angstrom. Scaling relations of the conformation-dependent sedi mentation coefficient, translational diffusion coefficient and intrinsic vi scosity with molecular weight have been considered in derail and are all in dicative of a spherical molecule with an inhomogeneous distribution of dens ity (Mark-Houwink-Kuhn-Sakurada a, b and epsilon, coefficients of similar t o 0.24, similar to 0.69 and similar to 0.31, respectively). (C) 1999 Elsevi er Science Ltd. All rights reserved.