Physical interactions of nanoparticles with biological membranes: The observation of nanoscale hole formation

Hong, Seungpyo; Hessler, Jessica A.; Holl, Mark M. Banaszak; Leroueil, Pascale R.; Mecke, Almut; Orr, Bradford G.

doi:10.1016/j.chs.2005.09.004

Cited by 35 publications

(40 citation statements)

References 32 publications

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“…15 Also of significance, previous work by other groups has shown that direct permeabilization of the plasma membrane is observed by branched and linear PEI, and this permeabilization is implicated as a potential mechanism of cytotoxicity. 1, 9, 25 It is possible that the different cytotoxic profiles observed for linear PEI vs. the PGAAs is a result of their different mechanisms of cellular entry. 15 …”

Section: Resultsmentioning

confidence: 99%

Membrane and Nuclear Permeabilization by Polymeric pDNA Vehicles: Efficient Method for Gene Delivery or Mechanism of Cytotoxicity?

2012

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The aim of this study is to compare the cytotoxicity mechanisms of linear PEI to two analogous polymers synthesized by our group: a hydroxyl-containing poly(L-tartaramidoamine) (T4) and a version containing an alkyl chain spacer poly(adipamidopentaethylenetetramine) (A4) by studying the cellular responses to polymer transfection. We have also synthesized analogues of T4 with different molecular weights (degrees of polymerization of 6, 12, and 43) to examine the role of molecular weight on the cytotoxicity mechanisms. Several mechanisms of polymer-induced cytotoxicity are investigated, including plasma membrane permeabilization, the formation of potentially harmful polymer degradation products during transfection including reactive oxygen species, and nuclear membrane permeabilization. We hypothesized that since cationic polymers are capable of disrupting the plasma membrane, they may also be capable of disrupting the nuclear envelope, which could be a potential mechanism of how the pDNA is delivered into the nucleus (other than nuclear envelope breakdown during mitosis). Using flow cytometry and confocal microscopy, we show that the polycations with the highest amount of protein expression and toxicity, PEI and T443, are capable of inducing nuclear membrane permeability. This finding is important for the field of nucleic acid delivery in that not only could direct nucleus permeabilization be a mechanism for pDNA nuclear import but also a potential mechanism of cytotoxicity and cell death. We also show that the production of reactive oxygen species is not a main mechanism of cytotoxicity, and that the presence or absence of hydroxyl groups as well as polymer length plays a role in polyplex size and charge in addition to protein expression efficiency and toxicity.

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Section: Resultsmentioning

confidence: 99%

Membrane and Nuclear Permeabilization by Polymeric pDNA Vehicles: Efficient Method for Gene Delivery or Mechanism of Cytotoxicity?

2012

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“…54 Large cationic G7 PAMAM dendrimers were able to cause holes in intact bilayers, whereas the smaller cationic G5 dendrimers increased the size of preexisting holes but did not generate new holes. Neutral dendrimers adsorbed to the edges of preexisting holes, 55 and removed lipids from the edge of the hole, and formed dendrimer-lipid aggregates.…”

Section: Plasma Membranementioning

confidence: 95%

The role of surface charge in cellular uptake and cytotoxicity of medical nanoparticles

Frőhlich¹

2012

IJN

2,010

1,416

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Many types of nanoparticles (NPs) are tested for use in medical products, particularly in imaging and gene and drug delivery. For these applications, cellular uptake is usually a prerequisite and is governed in addition to size by surface characteristics such as hydrophobicity and charge. Although positive charge appears to improve the efficacy of imaging, gene transfer, and drug delivery, a higher cytotoxicity of such constructs has been reported. This review summarizes findings on the role of surface charge on cytotoxicity in general, action on specific cellular targets, modes of toxic action, cellular uptake, and intracellular localization of NPs. Effects of serum and intercell type differences are addressed. Cationic NPs cause more pronounced disruption of plasma-membrane integrity, stronger mitochondrial and lysosomal damage, and a higher number of autophagosomes than anionic NPs. In general, nonphagocytic cells ingest cationic NPs to a higher extent, but charge density and hydrophobicity are equally important; phagocytic cells preferentially take up anionic NPs. Cells do not use different uptake routes for cationic and anionic NPs, but high uptake rates are usually linked to greater biological effects. The different uptake preferences of phagocytic and nonphagocytic cells for cationic and anionic NPs may influence the efficacy and selectivity of NPs for drug delivery and imaging.

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“…There has been work showing that branched 78 kDa PEI is capable of disrupting lipid membranes. 33–35 Indeed, if PEI is able to disrupt lipid membranes, it is possible that the observed loss of MMP is due to PEI disrupting the mitochondrial membrane. Researchers have previously suggested that one route to mitochondrial depolarization is the direct permeabilization of the outer mitochondrial membrane, allowing cytochrome c to escape the intermembrane space, leading to the activation of caspases and apoptosis.…”

Section: Introductionmentioning

confidence: 99%

Interaction of Poly(ethylenimine)–DNA Polyplexes with Mitochondria: Implications for a Mechanism of Cytotoxicity

2011

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Poly(ethylenimine) (PEI) and PEI-based systems have been widely studied for use as nucleic acid delivery vehicles. However, many of these vehicles display high cytotoxicity, rendering them unfit for therapeutic use. By exploring the mechanisms that cause cytotoxicity, and through understanding structure-function relationships between polymers and intracellular interactions, nucleic acid delivery vehicles with precise intracellular properties can be tailored for specific function. Previous research has shown that PEI is able to depolarize mitochondria, but the exact mechanism as to how depolarization is induced remains elusive and therefore is the focus of the current study. Potential mechanisms for mitochondrial depolarization include direct mitochondrial membrane permeabilization by PEI or PEI polyplexes, activation of the mitochondrial permeability transition pore, and interference with mitochondrial membrane proton pumps, specifically Complex I of the electron transport chain and F0F1-ATPase. Herein, confocal microscopy and live cell imaging showed that PEI polyplexes do colocalize to some degree with mitochondria early in transfection, and the degree of colocalization increases over time. Cyclosporine a was used to prevent activation of the mitochondrial membrane permeability transition pore, and it was found that early in transfection cyclosporine a was unable to prevent the loss of mitochondrial membrane potential. Further studies done using rotenone and oligomycin to inhibit Complex I of the electron transport chain and F0F1-ATPase, respectively, indicate that both of these mitochondrial proton pumps are functioning during PEI transfection. Overall, we conclude that direct interaction between polyplexes and mitochondria may be the reason why mitochondrial function is impaired during PEI transfection.

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Physical interactions of nanoparticles with biological membranes: The observation of nanoscale hole formation

Cited by 35 publications

References 32 publications

Membrane and Nuclear Permeabilization by Polymeric pDNA Vehicles: Efficient Method for Gene Delivery or Mechanism of Cytotoxicity?

Membrane and Nuclear Permeabilization by Polymeric pDNA Vehicles: Efficient Method for Gene Delivery or Mechanism of Cytotoxicity?

The role of surface charge in cellular uptake and cytotoxicity of medical nanoparticles

Interaction of Poly(ethylenimine)–DNA Polyplexes with Mitochondria: Implications for a Mechanism of Cytotoxicity

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