Characterizations of Polyamidoamine Dendrimers with Scattering Techniques

Abstract

Dendrimers are highly branched, open, covalent assemblies of branch cells (monomers) radially attached to a core in successive layers or generations. Major types of dendrimers include polyamidoamine, polypropylenimine, multiple antigen peptide, chiral, and Fréchet-type dendrimers. Their structure and dynamics can be explored by various techniques, such as scattering, spectrometry, and microscopy techniques. Specifically, the scattering techniques include small-angle neutron scattering (SANS), quasi-elastic neutron scattering (QENS), small-angle X-ray scattering (SAXS), and light scattering. Examples of their properties that can be explored by scattering techniques include: inter-molecular structure, intra-molecular cavity, radius-of-gyration (RG), hydrodynamic radius (RH), molecular weight, effective charge number of a single dendrimer molecule, water penetration into the interior of the dendrimers, and the internal dynamics. Of these properties, the hydrodynamic radius and molecular weight may be explored by DLS; the internal dynamics of dendrimers may be studied by QENS; and the others may be explored through SAXS and SANS. During the past several years, SANS and QENS have been used to study the structural properties and internal dynamics of various generations of polyamidoamine dendrimers (PAMAMs). Their potential prospects as anticancer polymer drug carriers are also discussed

Characterization of polyamidoamino (PAMAM) dendrimers using in-line reversed phase LC electrospray ionization mass spectrometry

“…In most cases there is no guidance given about how these were observed or under what circumstances they were encountered. There are, however, recent reports demonstrating the existence of two forms of dendrimer described as swollen and flat forms 16, 26, 27 . The mechanism of form conversion described in these papers involves a silica surface and a change in electrolyte concentration.…”

Dendrimers

“…58 The application of scattering techniques to characterize dendrimers allows the study of their intermolecular structure, intramolecular cavity, radius of gyration, hydrodynamic radius, molecular weight, effective charge number of a single dendrimer molecule, water penetration into the interior of the dendrimers and the internal dynamics. 62 Specifically, the scattering techniques (Chapter 2) include smallangle neutron scattering, quasi-elastic neutron scattering, small-angle X-ray scattering and light scattering. 62 7.2.3.2.2 Dendriplexes.…”

“…62 Specifically, the scattering techniques (Chapter 2) include smallangle neutron scattering, quasi-elastic neutron scattering, small-angle X-ray scattering and light scattering. 62 7.2.3.2.2 Dendriplexes. As spectroscopic methods, scattering techniques are used to study the formation of complexes between dendrimers and nucleic acids and to characterize them.…”

Dendrimers with Oligospiroketal (OSK) Building Blocks: Synthesis and Properties

“…The physical and biological properties of dendrimers depend on the conformational rigidity of the individual building blocks. This applies especially to the apparent size of dendrimer molecules, derivable from their hydrodynamic radius 3. Dendrimers consisting of rather flexible elements tend towards entanglement and back‐folding and thus minimize their entropy.…”