A Quantitative Assessment of Nanoparticle−Ligand Distributions: Implications for Targeted Drug and Imaging Delivery in Dendrimer Conjugates

Functional nanoparticles often contain ligands including targeting molecules, fluorophores, and/or active moieties such as drugs. Characterizing the number of these ligands bound to each particle and the distribution of nanoparticle−ligand species is important for understanding the nanomaterial’s fu...

Full description

Saved in:
Bibliographic Details
Published inACS nano Vol. 4; no. 2; pp. 657 - 670
Main Authors Mullen, Douglas G, Fang, Ming, Desai, Ankur, Baker, James R, Orr, Bradford G, Banaszak Holl, Mark M
Format Journal Article
LanguageEnglish
Published United States American Chemical Society 23.02.2010
Subjects
Alkynes - chemistry
Chromatography, Gel
Dendrimers - chemistry
Drug Carriers - chemistry
Ligands
Magnetic Resonance Spectroscopy
Molecular Imaging
Nanoparticles - chemistry
Potentiometry
ligand distribution
nanotechnology
drug delivery
nanoparticle characterization
PAMAM dendrimer
Online AccessGet full text

Cover

More Information
Summary:Functional nanoparticles often contain ligands including targeting molecules, fluorophores, and/or active moieties such as drugs. Characterizing the number of these ligands bound to each particle and the distribution of nanoparticle−ligand species is important for understanding the nanomaterial’s function. In this study, the amide coupling methods commonly used to conjugate ligands to poly(amidoamine) (PAMAM) dendrimers were examined. A skewed Poisson distribution was observed and quantified using HPLC for two sets of dendrimer−ligand samples prepared using the amine-terminated form of the PAMAM dendrimer and a partially acetylated form of the PAMAM dendrimer that has been used for targeted in vivo drug delivery. The prepared samples had an average number of ligands per dendrimer ranging from 0.4 to 13. Distributions identified by HPLC are in excellent agreement with the mean ligand/dendrimer ratio, measured by 1H NMR, gel permeation chromatography (GPC), and potentiometric titration. These results provide insight into the heterogeneity of distributions that are obtained for many classes of nanomaterials to which ligands are conjugated and belie the use of simple cartoon models that present the “average” number of ligands bound as a physically meaningful representation for the material.
ISSN:1936-0851
1936-086X
DOI:10.1021/nn900999c