PEGylated Polyamidoamine Dendrimers with Bis-Aryl Hydrazone Linkages for Enhanced Gene Delivery


Surface modification of polyamidoamine (PAMAM) dendrimers with polyethylene glycol (PEG) often results in the decrease in their buffering capacity, which is essential for gene transfer. In this work, bis-aryl hydrazone bond, which possesses protonatable pyridine and amines, was explored as a new linkage for PEGylation of PAMAM dendrimers. PEGylated polyamidoamine (PAMAM) dendrimer G4.0 conjugates with bis-aryl hydrazone (BAH) linkages were synthesized following a two-step procedure: activation of PAMAM dendrimer G4.0 and monofunctional methoxypolyethylene glycol amine (MW=5000 Da) with succinimidyl 4-hydrazinonicotinate acetone hydrazone (SANH) and succinimidyl 4-formylbenzoate (SFB), respectively, and coupling of SFB-activated PEG to SANH-activated G4.0 to generate PEGylated G4.0 with bis-aryl hydrazone linkages (G4.0-BAH-PEG). It was found that the incorporation of BAH linkages into the vector significantly enhanced the buffering capacity of the vector even with a high degree of PEGylation (42 PEG chains per dendrimer). G4.0-BAH-PEG conjugates could complex with DNA plasmid tightly at low weight ratios and display dramatically improved cytocompatibility. According to gene transfection studies in 293T and HN12 cells, this new vector has been shown to be capable of both transfecting more cells and inducing higher gene expression than the parent dendrimer. This work demonstrates that the use of the BAH linkage in coupling of PEG to the dendrimer helps maintain or increase the buffering capacity of the functionalized dendrimer and results in enhanced transfection.


Chemical and Biochemical Engineering

Keywords and Phrases

Buffering capacities; Cytocompatibility; DNA plasmids; Functionalized dendrimers; Gene Delivery; Gene transfection; Hydrazone bonds; Hydrazones; Low weight; Methoxypolyethylene glycol; Monofunctional; PAMAM dendrimer; PEgylation; Polyamidoamine dendrimers; Surface modification; Two-step procedure, Acetone; Dendrimers; Gene expression; Gene transfer; Nucleic acids; Organic compounds; Polyethylene glycols; Polyethylene oxides, Functional polymers, dendrimer; hydrazone derivative; macrogol; polyamidoamine; polymer, animal cell; article; chemical structure; cytotoxicity; flow cytometry; fluorescence microscopy; molecular weight; nonhuman; nonviral gene delivery system; priority journal; proton nuclear magnetic resonance; synthesis; Western blotting, Blotting, Western; Cell Line; Dendrimers; Flow Cytometry; Gene Transfer Techniques; Humans; Hydrazones; Magnetic Resonance Spectroscopy; Microscopy, Fluorescence; Polyethylene Glycols

International Standard Serial Number (ISSN)

1525-7797; 1526-4602

Document Type

Article - Journal

Document Version


File Type





© 2010 American Chemical Society (ACS), All rights reserved.

Publication Date

09 Aug 2010

PubMed ID