Characterization of commercially available and synthesized polyethylenimines for gene delivery

Harpe, Anke von; Petersen, Holger; Li, Youxin; Kissel, Thomas

doi:10.1016/s0168-3659(00)00317-5

Cited by 483 publications

(413 citation statements)

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“…The LMW-PEI was synthesized and extensively characterized as described by von Harpe et al 22 For complexation, 9 mg LMW-PEI was diluted in 8 ml bidistilled water, adjusted to pH 7.4, brought to 10 ml and sterile filtered (0.2 mm). The desired amounts of RNA or DNA and of polymer solution were each diluted to 250 ml with 150 mM NaCl pH 7.4 and vortexed.…”

Section: Synthesis Of Lmw-pei Preparation Of Lmw-pei/rna and Lmw-peimentioning

confidence: 99%

“…21 In in vitro experiments, LMW-PEI displays significantly lower toxicity combined with high DNA transfection efficiency when compared to HMW-PEI. 22 In this paper, we present a method for protection and cellular delivery of chemically unmodified RNA molecules in general and ribozymes in particular. Using LMW-PEI, ribozymes are efficiently stabilized against degradation and transfected into mammalian cells in vitro.…”

Section: Introductionmentioning

confidence: 99%

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Delivery of unmodified bioactive ribozymes by an RNA-stabilizing polyethylenimine (LMW-PEI) efficiently down-regulates gene expression

et al. 2002

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The sequence-specific cleavage of RNA molecules through ribozyme targeting is particularly attractive since it allows the effective abrogation of protein expression. So far, however, use of enzymatically active RNA molecules (ribozymes) has, without chemical modification, been severely hampered by ribozyme instability and poor cellular uptake. In this paper, we present a method for protection and cellular delivery of ribozymes by complexation with a low molecular weight polyethylenimine (LMW-PEI). We show that LMW-PEI almost completely stabilizes ribozymes or any RNA against degradation in vitro. Upon their highly efficient cellular uptake, non-toxic LMW-PEI-complexed ribozymes display intracellular bioactivity already at low concentrations as demonstrated by down-regulation of two different genes in different cell lines. In vivo, LMW-PEI-complexed ribozymes were stabilized after intraperitoneal (i.p.) injections, showed prolonged circulation time and intact ribozymes were detected in the subcutaneous (s.c.) tumor mass 60 min after the injection. In addition, i.p. injections of LMW-PEI-complexed ribozymes targeted against the growth factor pleiotrophin (PTN) resulted in marked reduction of s.c. human melanoma tumor growth and of intratumoral PTN levels in a mouse xenograft model. Thus, this paper describes a novel method for exogenous delivery of any bioactive RNA ribozyme in vitro and in vivo without chemical modification.

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Section: Synthesis Of Lmw-pei Preparation Of Lmw-pei/rna and Lmw-peimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Delivery of unmodified bioactive ribozymes by an RNA-stabilizing polyethylenimine (LMW-PEI) efficiently down-regulates gene expression

et al. 2002

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“…An analogy between AB 2 polycondensation and ring-opening multi-branching polymerizations can be established [31], and therefore it is hypothesized that the methodologies applicable to HBPs obtained by random polycondensation processes can be also used for poly(ethyleneimine) polymers. The batch synthesis of hyperbranched polyethyleneimines in aqueous solution has been reported [36], leading to polymers with an amine ratio of approximately 1:2:1 determined by NMR. However, commercial polymers may have different amine ratios, about 1:1:1 [36], and with very narrow polymer distribution [37], indicating that the synthetic procedure may be different such as slow monomer addition [31] or else have been synthesized with the addition of a core molecule to control the polymer distribution, as reported in the patent literature [38].…”

Section: Introductionmentioning

confidence: 99%

Structural analysis of the curing of epoxy thermosets crosslinked with hyperbranched poly(ethyleneimine)s

Fernández‐Francos

Ramis

2015

European Polymer Journal

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The network build-up process during curing of an epoxy resin using a hyperbranched poly(ethyleneimine) as crosslinking agent has been studied from a theoretical and experimental point of view. A systematic analysis taking into account the stoichiometry of the curing process has been performed. Conversion at gelation has been studied by thermomechanical analysis (TMA) and differential scanning calorimetry (DSC). Crosslinking density has been studied by dynamomechanical analysis (DMA). Gel fraction after extraction in organic solvents has also been determined. The experimental results have been compared with a theoretical network build-up model based on the random recombination of structural fragments, showing good agreement between theory and experimental results, but deviations from the ideal epoxy-amine polycondensation appear as a consequence of the dilution of the hyperbranched crosslinker in off-stoichiometric formulations.  Expressions for relevant pre-gel and post-gel statistical averages are derived.  Experimental validation of predicted crosslinking and gelation is performed.  Nonidealities due to the densely branched structure of the crosslinker are described. ABSTRACTThe network build-up process during curing of an epoxy resin using a hyperbranched poly(ethyleneimine)as crosslinking agent has been studied from a theoretical and experimental point of view. A systematic analysis taking into account the stoichiometry of the curing process has been performed. Conversion at gelation has been studied by thermomechanical analysis (TMA) and differential scanning calorimetry (DSC). Crosslinking density has been studied by dynamomechanical analysis (DMA). Gel fraction after extraction in organic solvents has also been determined. The experimental results have been compared with a theoretical network build-up model based on the random recombination of structural fragments,showing good agreement between theory and experimental results, but deviations from the ideal epoxyamine polycondensation appear as a consequence of the dilution of the hyperbranched crosslinker in offstoichiometric formulations.

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“…[3][4][5][6][7][8][9][10][11] A branched polymer containing primary, secondary, and tertiary amines, PEI is capable of complexing plasmid DNA and delivering it intracellularly to cells in vitro. The amine groups of PEI are thought to act as proton sponges, preventing endosomal acidification, which results in osmotic swelling and disruption of endosomal membranes.…”

Section: Introductionmentioning

confidence: 99%

Quantitative comparison of polyethylenimine formulations and adenoviral vectors in terms of intracellular gene delivery processes

et al. 2005

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An objective of designing molecular vehicles exhibiting viruslike transgene delivery capabilities but with low toxicity and immunogenicity continues to drive synthetic vector development. As no single step within the gene delivery pathway represents the critical limiting barrier for all vector types under all circumstances, improvements in synthetic vehicle design may be aided by quantitative analysis of the contributions of each step to the overall delivery process. To our knowledge, however, synthetic and viral gene delivery methods have not yet been explicitly compared in terms of these delivery pathway steps in a quantitative manner. As a first address of this challenge, we compare here quantitative parameters characterizing intracellular gene delivery steps for an E1/E3-deleted adenoviral vector and three polyethylenimine (PEI)-based vector formulations, as well as the liposomal transfection reagent Lipofectamine and naked DNA; the cargo is a plasmid encoding the b-galactosidase gene under a CMV promoter, and the cell host is the C3A human hepatocellular carcinoma line. The parameters were determined by applying a previously validated mathematical model to transient time-course measurements of plasmid uptake and trafficking (from whole-cell and isolated nuclei lysates, by real-time quantitative PCR), and gene expression levels, enabling discovery of those for which the adenoviral vector manifested superiority. Parameter-sensitivity analysis permitted identification of processes most critically ratelimiting for each vector. We find that the adenoviral vector advantage in delivery appears to reside partially in its import to the nuclear compartment, but that its vast superiority in transgene expression arises predominantly in our situation from postdelivery events: on the basis of per-nuclear plasmid, expression efficiency from adenovirus is superior by orders of magnitude over the PEI vectors. We find that a chemical modification of a PEI-based vector, which substantially improves its performance, appears to do so by enhancing certain trafficking rate parameters, such as binding and uptake, endosomal escape, and binding to nuclear import machinery, but leaves endosomal escape as a barrier over which transgene delivery could be most sensitively increased further for this polymer.

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Characterization of commercially available and synthesized polyethylenimines for gene delivery

Cited by 483 publications

References 21 publications

Delivery of unmodified bioactive ribozymes by an RNA-stabilizing polyethylenimine (LMW-PEI) efficiently down-regulates gene expression

Delivery of unmodified bioactive ribozymes by an RNA-stabilizing polyethylenimine (LMW-PEI) efficiently down-regulates gene expression

Structural analysis of the curing of epoxy thermosets crosslinked with hyperbranched poly(ethyleneimine)s

Quantitative comparison of polyethylenimine formulations and adenoviral vectors in terms of intracellular gene delivery processes

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