Specific effects of PEGylation on gene delivery efficacy of polyethylenimine: Interplay between PEG substitution and N/P ratio

Fitzsimmons, Ross; Uludağ, Hasan

doi:10.1016/j.actbio.2012.07.015

Cited by 63 publications

(54 citation statements)

References 35 publications

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“…On the other hand, many studies showed that PEGylation of dendrimers increases their solubility, enhances structural stability, improves biocompatibility, prolongs blood circulation halflife, decreases the immunogenicity, reduces intermolecular aggregation, and finally helps to avoid their rapid clearance by reticulo-endothelial system (RES) [11,12,[16][17][18]. Polyethylene glycol (PEG) has been widely used in the polymeric gene carriers; however, it was shown that PEGylation could improve or decrease transfection activity of polymers [19,20].…”

Section: Introductionmentioning

confidence: 99%

PEGylation of Polypropylenimine Dendrimer with Alkylcarboxylate Chain Linkage to Improve DNA Delivery and Cytotoxicity

Hashemi

Ayatollahi

Parhiz

et al. 2015

Appl Biochem Biotechnol

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One of the major limitations of effective nonviral gene carriers is their potential high cytotoxicity. Conjugation of polyethylene glycol (PEG) to polymers is a common approach to decrease toxicity and improve biodistribution. The aim of this study was to evaluate the effect of PEGylation on generation 5 polypropylenimine (PPI) dendrimer by using PEG moieties or alkyl-PEG groups. Polymers were synthesized by grafting of 5 and 10 % primary amines of PPI to NH2-PEG-COOH or Br-(CH2)9-CO-NH-PEG-COOH through Amide bond formation or nucleophilic substitution, respectively. Transfection efficiency and cytotoxicity were analyzed after 4 and 24 h exposure of neuroblastoma cell line (Neuro-2a) with synthesized vectors. Among all of the PEG-PPI derivatives, 5 % PEG-conjugated G5 PPI with alkyl chain (PPI-alkyl-PEG 5 %) resulted in the most efficient gene expression. This vector also significantly decreased the in vitro cytotoxicity and sub-G1 peak in flow cytometry histogram after 24 h incubation. Our results indicate that modification of 5 % primary amines of G5 PPI with PEG using alkyl chain as linker produces a promising vector combining low cytotoxicity, appropriate biodegradability, and high gene transfection efficiency.

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Section: Introductionmentioning

confidence: 99%

PEGylation of Polypropylenimine Dendrimer with Alkylcarboxylate Chain Linkage to Improve DNA Delivery and Cytotoxicity

Hashemi

Ayatollahi

Parhiz

et al. 2015

Appl Biochem Biotechnol

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“…57,58 Potential cytotoxicity of bPEI is another challenge for a successful gene delivery. 50 A noticeable reduction of bPEI cytotoxicity was achieved following L-histidine substitution ( Figure 8). The amine groups of bPEI are active sites to induce cytotoxicity.…”

Section: Discussionmentioning

confidence: 96%

“…50 To investigate stability of the polyplex nanoparticles, they were challenged against heparin displacement. 51 PEG-stabilized bPEI or PEI-Histidine polyplexes showed more resistance against heparin sulfate than non-PEGylated bPEI or PEI-Histidine ( Figure 5(B)).…”

Section: Discussionmentioning

confidence: 99%

Serum resistant and enhanced transfection of plasmid DNA by PEG-stabilized polyplex nanoparticles of L-histidine substituted polyethyleneimine

et al. 2015

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To improve transfection of plasmid DNA as well as serum protein stability of polyionic complex nanoparticles of branched polyethyleneimine (bPEI), poly(ethylene glycol) (PEG)-stabilized nanoparticles were made from L-histidine substituted bPEI (PEI-Histidine) synthesized by Fmoc chemistry. The polymer was characterized by TNBS assay, 1 H NMR, GFC, potentiometric titration and elemental analysis of carbon and nitrogen, DNA condensation, and the stability against extracellular matrix (heparin sulfate) was investigated by dye exclusion and agarose gel retardation assays. The nanoparticles were characterized by dynamic light scattering-zeta potential analyzer. Cytotoxicity and expression of enhanced green fluorescent protein (EGFP) were determined in hepatocellular carcinoma by MTT assay and fluorescent techniques. PEI-Histidine showed a reduced pK a without any significant loss of total primary amines. Plasmid DNA was condensed almost thoroughly with PEGylated polymers, either bPEI or PEI-Histidine, at lower critical N/P ratios. PEGylated PEI-Histidine showed the better resistance to heparin induced displacement and the lower cytotoxicity when it was compared to bPEI. Interestingly unlike bPEI, smaller and less positively charged nanoparticles were obtained from PEGylated PEI-Histidine at N/P ratio=2 that resulted in about 4 folds higher EGFP expression than bPEI without any significant cytotoxicity. These properties are consistent with the higher serum protein resistance and buffer capacity of PEGylated PEI-Histidine at endosomal acidic pH.

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“…3A), which could be attributed to cell death by the charge-induced cell membrane damage at high amounts of cationic polymers [18,19,47]. The addition of PEG-CG to PEI-CG10-PEI remarkably enhanced the cell viability at the N/P ratios ranging from 2 to 12, suggesting the shielding effect of PEG on the surface charge of polyplexes [20,21]. However, such an effect was not significant for PEI-CG6-PEI copolymer at most of the N/P ratios.…”

Section: Cytotoxicity and Dna Transfectionmentioning

confidence: 99%

“…However, the relatively high toxicity of PEI, which has been attributed to both necrotic and apoptotic mechanisms resulting from cell membrane damage [18,19], is one of the major factors limiting its use, especially for in vivo applications. An effective strategy to reduce the toxicity of PEI has been demonstrated by covalent attachment of poly(ethylene glycol) (PEG) to PEI polymers [20,21]. As a nonionic hydrophilic polymer, PEG could shield the surface charge of polyplexes and reduce the intermolecular interactions by forming a hydration shell around the polyplexes, and hence decrease their toxicity.…”

Section: Introductionmentioning

confidence: 99%

Engineering biodegradable micelles of polyethylenimine-based amphiphilic block copolymers for efficient DNA and siRNA delivery

Wang

Balk

Deng

et al. 2016

Journal of Controlled Release

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Polycationic micelles have shown advantageous properties as nucleic acid delivery vectors both in vitro and in vivo. In contrast to polycationic micelles reported so far, we designed particles integrating a sufficient nucleic acid condensation capability by polycationic polyethylenimine (PEI) segments as well as only a mild cytotoxic behavior. The micelles composed of a hydrophobic oligoester core with glycolide units resulting in fast degradation after cellular internalization in combination with PEG moieties acting as shielding agents. By grafting branched 25 kDa polyethylenimine (PEI25) and poly(ethylene glycol) (PEG) on poly[(ε-caprolactone)-co-glycolide] (CG), amphiphilic PEI-CG-PEI and PEG-CG block copolymers were used to form a series of micelles via self-assembly of PEI-CG-PEI or coassembly of both copolymers for DNA and siRNA delivery. This modular system enabled a systematic investigation of different parameters and their synergetic effects as different functions were introduced. The polyplex formation and serum stability, cytotoxicity, and transfection activity could be tailored by changing the CG chain length in PEI-based copolymer, incorporating PEG-CG, and varying the N/P ratio. All micelle-based polyplex compositions showed high DNA transfection activity according to reporter gene-expression and an exceptionally high knockdown in siRNA delivery experiments. Remarkably, the GFP expression of >99% cells was successfully knocked down by micelle-mediated siRNA interference, resulting in a decrease of two orders of magnitude in fluorescence intensity.Incorporation of PEG-CG in the micelles reduced the PEI-related cytotoxicity, and markedly enhanced the serum stability of both DNA and siRNA polyplexes. Compared with homo-PEI25, these micelles showed several advantages including the lower toxicity, higher siRNA transfection efficiency and higher polyplex stability in the presence of serum. This study therefore provides an effective approach to tune the structure, property and function of polycationic micelles for efficient DNA and siRNA delivery, which could contribute to the design and development of novel non-viral transfection vectors with superb functionality.

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Specific effects of PEGylation on gene delivery efficacy of polyethylenimine: Interplay between PEG substitution and N/P ratio

Cited by 63 publications

References 35 publications

PEGylation of Polypropylenimine Dendrimer with Alkylcarboxylate Chain Linkage to Improve DNA Delivery and Cytotoxicity

PEGylation of Polypropylenimine Dendrimer with Alkylcarboxylate Chain Linkage to Improve DNA Delivery and Cytotoxicity

Serum resistant and enhanced transfection of plasmid DNA by PEG-stabilized polyplex nanoparticles of L-histidine substituted polyethyleneimine

Engineering biodegradable micelles of polyethylenimine-based amphiphilic block copolymers for efficient DNA and siRNA delivery

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