Physicochemical characterization of generation 5 polyamidoamine dendrimers.
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.
Nourse
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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.
Millar
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Minton
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AP
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*
D001672:Biocompatible Materials; D050091:Dendrimers; C104700:PAMAM Starburst; D011073:Polyamines