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) M sD 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 M sD 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).