Quantitative analysis of generation and branch defects in G5 poly(amidoamine) dendrimer.
Although methods have been developed to synthesize and isolate generation 5 (G5) PAMAM dendrimers containing precise numbers of ligands per polymer particle, the presence of skeletal and generational defects in this material can substantially hamper the process. Here we provide a quantitative analysis of G5 PAMAM dendrimer defects via high performance liquid chromatography, potentiometric titration, mass spectrometry, size exclusion chromatography, and nuclear magnetic resonance. We identified, isolated, and characterized the major structural defects of G5 dendrimer, trailing generations, and dimer, trimer, and tetramer species. We determine that the G5 material present in the as-received mixture contains 93 arms on average. We have developed two model systems capable of generating the experimentally observed mass range and polydispersity at defect rates of 8-15%.
Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA ; Michigan Nanotechnology Institute for Medicine and Biological Sciences, University of Michigan, Ann Arbor, MI 48109, USA.
Mallory A
MA
van Dongen
Ankur
A
Desai
Bradford G
BG
Orr
James R
JR
Baker
Mark M Banaszak
MM
Holl
HPLC; Mass spectrometry; PAMAM dendrimer