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Partitioning of Poly(amidoamine) Dendrimers between n-Octanol and Water

Giri, Jyotsnendu and Diallo, Mamadou S. and Goddard, William A., III and Dalleska, Nathan F. and Fang, Xiangdong and Tang, Yongchun (2009) Partitioning of Poly(amidoamine) Dendrimers between n-Octanol and Water. Environmental Science and Technology, 43 (13). pp. 5123-5129. ISSN 0013-936X.

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Dendritic nanomaterials are emerging as key building blocks for a variety of nanoscale materials and technologies. Poly(amidoamine) (PAMAM) dendrimers were the first class of dendritic nanomaterials to be commercialized. Despite numerous investigations, the environmental fate, transport, and toxicity of PAMAM dendrimers is still not well understood. As a first step toward the characterization of the environmental behavior of dendrimers in aquatic systems, we measured the octanol−water partition coefficients (logK_(ow)) of a homologous series of PAMAM dendrimers as a function of dendrimer generation (size), terminal group and core chemistry. We find that the logKow of PAMAM dendrimers depend primarily on their size and terminal group chemistry. For G1-G5 PAMAM dendrimers with terminal NH_2 groups, the negative values of their logK_(ow) indicate that they prefer to remain in the water phase. Conversely, the formation of stable emulsions at the octanol−water (O/W) interface in the presence of G6-NH_2 and G8-NH_2 PAMAM dendrimers suggest they prefer to partition at the O/W interface. In all cases, published studies of the cytotoxicity of Gx-NH_2 PAMAM dendrimers show they strongly interact with the lipid bilayers of cells. These results suggest that the logKow of a PAMAM dendrimer may not be a good predictor of its affinity with natural organic media such as the lipid bilayers of cell membranes.

Item Type:Article
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URLURL TypeDescription
Diallo, Mamadou S.0000-0002-2571-1568
Goddard, William A., III0000-0003-0097-5716
Dalleska, Nathan F.0000-0002-2059-1587
Additional Information:© 2009 American Chemical Society. Received February 5, 2009. Revised manuscript received April 27, 2009. Accepted April 29, 2009. Publication Date (Web): May 19, 2009. This work was carried out in the Materials Process Simulation Center and Power, Environmental and Energy Research Center of the Division of Chemistry and Chemical Engineering at the California Institute of Technology. Funding was provided by the Environmental Protection Agency (EPA STAR Grant RD832525) and the National Science Foundation (NIRT CBET Award No. 050695). Supporting Information: Further details are shown in three tables and six figures. This material is available free of charge via the Internet at
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Environmental Protection Agency (EPA)RD832525
Issue or Number:13
Record Number:CaltechAUTHORS:20090828-122206220
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:15412
Deposited By: George Porter
Deposited On:14 Sep 2009 17:33
Last Modified:09 Mar 2020 13:18

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