Hydrodynamic properties of carbohydrate-coated dendrimers

Abstract

The hydrodynamic properties of poly(propylene imine) dendrimers, modified with outer-surface β-thiolactosyl residues ("lactodendrimers") of generation number 1-5, have been investigated by velocity sedimentation, translational diffusion, and viscosity measurements in 0.165% NaCl aqueous solution. It has been demonstrated that apparent molecular weights (from the Svedberg equation) MsD of synthetic lactodendrimers, determined by sedimentation and diffusion experiments, are consistent with complete functionalization of initial poly(propylene imine) dendrimers with sugar residues. The values of MsD range from 1900 to 45000 Da for generation numbers 1-5. Corresponding hydrodynamic ("equivalent Stokes") radii range from ~10 to ~37 Å. Scaling relations of the conformation-dependent sedimentation coefficient, translational diffusion coefficient and intrinsic viscosity with molecular weight have been considered in detail and are all indicative of a spherical molecule with an inhomogeneous distribution of density (Mark-Houwink-Kuhn-Sakurada a, b and ε, coefficients of ~0.24, ~0.69 and ~0.31, respectively). © 1998 Elsevier Science Ltd.