title: Physicochemical characterization of generation 5 polyamidoamine dendrimers.
abstract: The dispersity, size, and self-interaction of generation 5 polyamidoamine dendrimeric polymers with different terminal groups (surfaces) were characterized using several physicochemical techniques. Amino-surface dendrimers form oligomeric aggregates in aqueous solution, even in the presence of high salt concentrations (0.6M sodium phosphate). In contrast, the hydroxyl-surface polymer G5-OH behaves as a single homogeneous (or paucidisperse) species at low concentration. Measurements of density increment and the sedimentation and diffusion coefficients of G5-OH suggest a more swollen, porous structure than a globular protein of comparable mass. Measurements of the concentration dependence of sedimentation equilibrium of G5-OH in pH 7.2 phosphate buffer indicate the presence of significant electrostatic repulsion overlaid on weakly attractive interactions, leading to the formation of nonspecific aggregates at sufficiently high dendrimer concentration.
authors.affiliation: Section on Physical Biochemistry, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda MD 20892-0830, USA.
authors.forename: A
authors.initials: A
authors.lastname: Nourse
authors.forename: D B
authors.initials: DB
authors.lastname: Millar
authors.forename: A P
authors.initials: AP
authors.lastname: Minton
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry; D002499:Centrifugation, Density Gradient; D002850:Chromatography, Gel; D050091:Dendrimers; D004591:Electrophoresis, Polyacrylamide Gel; D008968:Molecular Conformation; D008970:Molecular Weight; D010316:Particle Size; D011073:Polyamines / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D050091:Dendrimers; C104700:PAMAM Starburst; D011073:Polyamines