Opposites attract: influence of the molar mass of branched poly(ethylene imine) on biophysical characteristics of siRNA-based polyplexese

Wagner, Michael R.; Rinkenauer, Alexandra C.; Schallon, Anja; Schubert, Ulrich S.

doi:10.1039/c3ra42069h

Cited by 30 publications

(32 citation statements)

References 61 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…37, 38 These studies also report that the cytotoxicity of PEI increases as its molecular weight increases 35, 39 and that most branched PEIs are nontoxic below 25 kDa. 40 To test the cytotoxicity of BPEI used in these experiments (MW ~0.5 kDa), mouse fibroblasts (NIH/3T3 cells) were incubated over three days in the presence of varying concentrations of BPEI (supplemental data, Figure S3). Viability was determined using the MTT assay, following the protocol of Hansen et al .…”

Section: Resultsmentioning

confidence: 99%

Efficacy of ampicillin against methicillin-resistant Staphylococcus aureus restored through synergy with branched poly(ethylenimine)

et al. 2016

View full text Add to dashboard Cite

Beta-lactam antibiotics kill Staphylococcus aureus bacteria by inhibiting the function of cell-wall penicillin binding proteins (PBPs) 1 and 3. However, β-lactams are ineffective against PBP2a, used by methicillin-resistant Staphylococcus aureus (MRSA) to perform essential cell wall crosslinking functions. PBP2a requires teichoic acid to properly locate and orient the enzyme, and thus MRSA is susceptible to antibiotics that prevent teichoic acid synthesis in the bacterial cytoplasm. As an alternative, we have used branched poly(ethylenimine), BPEI, to target teichoic acid in the bacterial cell wall. The result is restoration of MRSA susceptibility to the β-lactam antibiotic ampicillin with a MIC of 1 μg/mL, superior to that of vancomycin (MIC = 3.7 μg/mL). A checkerboard assay shows synergy of BPEI and ampicillin. Nuclear magnetic resonance (NMR) data show that BPEI alters the teichoic acid chemical environment. Laser scanning confocal microscopy (LSCM) images show BPEI residing on the bacterial cell wall where teichoic acids and PBPs are located.

show abstract

Section: Resultsmentioning

confidence: 99%

Efficacy of ampicillin against methicillin-resistant Staphylococcus aureus restored through synergy with branched poly(ethylenimine)

et al. 2016

View full text Add to dashboard Cite

show abstract

“…10,11,25 For example, Kwok and Hart 11 showed that the addition of approximately five times as much heparin sulfate was required to restore the fluorescence of fluorescence-labeled pDNA after complexation with PEI compared to what was required to restore fluorescence of labeled siRNA in PEI/siRNA complexes. While the greater stability of PEI/pDNA complexes has been consistently observed, the specific reasons for this difference have not been delineated.…”

Section: Introductionmentioning

confidence: 99%

Structural Comparisons of PEI/DNA and PEI/siRNA Complexes Revealed with Molecular Dynamics Simulations

et al. 2017

View full text Add to dashboard Cite

Polyplexes composed of polyethyleneimine (PEI) and DNA or siRNA have attracted great attention for their use in gene therapy. While many physicochemical characteristics of these polyplexes remain unknown, PEI/DNA complexes have been repeatedly shown to be more stable than their PEI/siRNA counterparts. Here, we examine potential causes for this difference using atomistic molecular dynamics simulations of complexation between linear PEI and DNA or siRNA duplexes containing the same number of bases. The two types of polyplexes are stabilized by similar interactions, as PEI amines primarily interact with nucleic acid phosphate groups but also occasionally interact with groove atoms of both nucleic acids. However, the number of interactions in PEI/DNA complexes is greater than in comparable PEI/siRNA complexes, with interactions between protonated PEI amines and DNA being particularly enhanced. These results indicate that structural differences between DNA and siRNA may play a role in the increased stability of PEI/DNA complexes. Additionally, we investigate the binding of PEI chains to polyplexes that have a net positive charge. Binding of PEI to these overcharged complexes involves interactions between PEI and areas on the nucleic acid surface that have maintained a negative electrostatic potential and is facilitated by the release of water from the nucleic acid.

show abstract

“…9,15,16 Beside, it was elucidated that the polymer architecture has an important impact. Varying the chain length, composition, functionalisation, or architecture leads to different properties and efficiencies.…”

Section: Introductionmentioning

confidence: 99%

The influence of polymer architecture on in vitro pDNA transfection

et al. 2015

Self Cite

View full text Add to dashboard Cite

In 2012, the first gene therapy agent was approved by the Europe Medicines Agency leading to increased interest in this research field. Beside viruses, non-viral agents based on lipids or polymers represent aspiring alternatives to deliver the genetic material. Different hurdles have to be overcome depending on the kind of nucleic acid used, where plasmid DNA (pDNA) and small interfering RNA represent the common ones. The main challenge for transfection agents, in particular for pDNA delivery, is the transfer to the cell and into the cell nuclei. Within the group of transfection vesicles, cationic polymers show promising features and variability, as they can be synthesized with tailor-made physical and chemical properties (architectures and functionalisation). In the field of polymer-based gene delivery, the tuning potential of polymers by using different architectures like graft and star-shaped polymers as well as self-assembled block copolymers is immense. In particular, in the last few years numerous new polymer designs showed enhanced transfection properties in combination with good biocompatibility. Furthermore, new insights into the transfection mechanism demonstrated the continuous progress in this field. Polymer architecture influences the polyplex characteristics and the latter has an impact on the transfection mechanism, e.g. the interaction with the cellular membrane depends on the polyplex shape. Moreover, polyplex dissociation can be easily influenced by the polymer chemistry, thus biodegradable linkers lead to well suited polymers with reduced toxicity and high delivery potential, and are also promising for in vivo applications. This review focuses on the influence of polymer architectures for pDNA transfection in vitro, showing recent developments and insights. The theoretical background concerning the biological challenges for cationic polymers and the impact of graft-or star-shaped architectures as well as self-assembled structures will be presented in detail.

show abstract

Opposites attract: influence of the molar mass of branched poly(ethylene imine) on biophysical characteristics of siRNA-based polyplexese

Cited by 30 publications

References 61 publications

Efficacy of ampicillin against methicillin-resistant Staphylococcus aureus restored through synergy with branched poly(ethylenimine)

Efficacy of ampicillin against methicillin-resistant Staphylococcus aureus restored through synergy with branched poly(ethylenimine)

Structural Comparisons of PEI/DNA and PEI/siRNA Complexes Revealed with Molecular Dynamics Simulations

The influence of polymer architecture on in vitro pDNA transfection

Contact Info

Product

Resources

About