An Imidazolium-Based Lipid Analogue as a Gene Transfer Agent

Article abstract of DOI:10.1002/chem.202003466

A dicationic imidazolium salt is described and investigated towards its application for gene transfer. The polar head group and the long alkyl chains in the backbone contribute to a lipid-like behavior, while an alkyl ammonium group provides the ability for crucial electrostatic interaction for the transfection process. Detailed biophysical studies regarding its impact on biological membrane models and the propensity of vesicle fusion are presented. Fluorescence spectroscopy, atomic force microscopy and confocal fluorescence microscopy show that the imidazolium salt leads to negligible changes in lipid packing, while displaying distinct vesicle fusion properties. Cell culture experiments reveal that mixed liposomes containing the novel imidazolium salt can serve as plasmid DNA delivery vehicles. In contrast, a structurally similar imidazolium salt without a second positive charge showed no ability to support DNA transfection into cultured cells. Thus, we introduce a novel and variable structural motif for cationic lipids, expanding the field of lipofection agents.

Full text of DOI:10.1002/chem.202003466

Accepted Article
Accepted Article
Title: An Imidazolium-based Lipid Analogue as Gene Transfer Agent
Authors: Tiffany O. Paulisch, Steffen Bornemann, Marius Herzog,
Sergej Kudruk, Lena Roling, Anna Livia Linard Matos, Hans-
Joachim Galla, Volker Gerke, Roland Winter, and Frank
Glorius
This manuscript has been accepted after peer review and appears as an
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of the final Version of Record (VoR). This work is currently citable by
using the Digital Object Identifier (DOI) given below. The VoR will be
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content of this Accepted Article.
To be cited as: Chem. Eur. J. 10.1002/chem.202003466
Link to VoR: https://doi.org/10.1002/chem.202003466
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1/2020

Chemistry - A European Journal
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RESEARCH ARTICLE
An Imidazolium-based Lipid Analogue as Gene Transfer Agent
Tiffany O. Paulisch, a]+ Steffen Bornemann,[b]+ Marius Herzog,[b]+ Sergej Kudruk,[c]+ Lena Roling, Anna
[
[a]
[
c]
[d]
[c]
[b]
[a]
Livia Linard Matos, Hans-Joachim Galla, Volker Gerke,* Roland Winter,* Frank Glorius*
[
[
[
[
a]
b]
c]
d]
T. O. Paulisch, Dr. L. Roling, Prof. Dr. F. Glorius
Institute of Organic Chemistry, University of Münster, Corrensstraße 40, D-48149 Münster, Germany
glorius@uni-muenster.de
Dr. S. Bornemann, M. Herzog, Prof. Dr. R. Winter
Physical Chemistry I - Biophysical Chemistry, TU Dortmund University, D-44221 Dortmund, Germany
roland.winter@tu-dortmund.de
S. Kudruk, A. L. Linard Matos, Prof. Dr. V. Gerke
Institute of Medical Biochemistry, University of Münster, D-48149 Münster, Germany
gerke@uni-muenster.de
Prof. Dr. H.-J. Galla
Institute of Biochemistry, University of Münster, D-48149 Münster, Germany
These authors contributed equally to this work.
+
Supporting information for this article is given via a link at the end of the document.
Abstract: A novel, dicationic imidazolium salt is described and
charged cargo leads to the desired nucleic acid - lipid complex.[5]
It is thought that the cationic lipoplex is attracted by the anionic
biological target membrane and enables the delivery of the
negatively charged genetic material into the cytosol by direct
fusion or endocytosis – presumably via induction of transient and
local non-lamellar phases in the lipoplex membrane.[
investigated towards its application for gene transfer. The polar head
group and the long alkyl chains in the backbone contribute to a lipid-
like behavior, while an alkyl ammonium group provides the ability for
crucial electrostatic interaction for the transfection process. Detailed
biophysical studies regarding its impact on biological membrane
models and the propensity of vesicle fusion are presented.
Fluorescence spectroscopy, atomic force microscopy and confocal
fluorescence microscopy show that the imidazolium salt leads to
negligible changes in lipid packing, while displaying distinct vesicle
fusion properties. Cell culture experiments reveal that mixed
liposomes containing the novel imidazolium salt can serve as plasmid
DNA delivery vehicles. In contrast, a structurally similar imidazolium
salt without a second positive charge showed no ability to support
DNA transfection into cultured cells. Thus, we introduce a novel and
variable structural motif for cationic lipids, expanding the field of
lipofection agents.
6]
Despite its currently low in vivo efficiency, non-viral gene transfer
represents a promising alterative since the methodology is
expected to be immunologically inert and it is convenient to
prepare the aforementioned lipoplexes. To address current
challenges such as in vivo transfection efficiencies, accessible
synthesis of the cationic lipids and cellular specifications, a series
of different cationic lipids and polymers have been introduced.[
In this regard, we hypothesized that, owing to their inherent
positive charge, imidazolium salts could serve as potent
transfection agents.
7]
Introduction
In the context of gene therapy, one major challenge is the
controlled insertion of foreign nucleic acids into a target cell,
enabling the expression of these genes in the target. This process
called gene transfection has been
a
major focus of
pharmaceutical research within recent decades and can be
realized by different physical, biological and chemical means.[1]
Especially the transport via viral vectors and lipoplexes was
applied in gene therapy.[2]
Transfection through viral vectors has shown high transfection
efficiency in vivo, but the risk of an immune response presents a
major drawback.[3] An alternative approach for gene transfection,
namely lipofection, is based on the transport of nucleic acids
enclosed in liposomes or covered in sheets of cationic lipid
membranes. Such cationic lipids complex the negatively charged
cargo due to their positively charged head group, concealing the
negative charge of the genetic material, and therefore enabling
the passage through the anionic lipid bilayer (see Scheme 1).[4] In
comparison to viral vectors, the preparation of lipoplexes is rather
simple, since mixing of the cationic lipids with the negatively
Scheme 1. Design of
application as a gene transfer reagent. Blue – neutral lipids (i.e. DPPC, DOPE,
DOPC), Red negatively charged lipids (i.e. DOPG, DPPG), Green
imidazolium-based lipid analogue.
3
a dicationic imidazolium-based lipid IMeNMe for
–
–
[
8]
Within the last years, imidazolium salts have gained considerable
attention across diverse fields of chemistry, biology and material
sciences. Their function as precursors for N-heterocyclic
carbenes has made them essential for both transition-metal and
organocatalysis.[9] Moreover, their facile synthesis allows for the
1
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Chemistry - A European Journal
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RESEARCH ARTICLE
design of tailor-made molecules – installing up to five different
substituents on the five-membered heterocycle.[10]
This structural diversity has led to the development of important
applications in the field of ionic liquids and also in biological
contexts, where imidazolium salts can serve as artificial anion
transporters, as medication for cancer treatment or as
antimicrobial and antifungal drugs.[11,12,13] Furthermore, recent
studies showed remarkable membrane activities of imidazolium
salts,[14] and demonstrated pronounced detergent-like properties
depending on their alkyl chain length and cationic headgroup
structure.[15,12] In this context, we could show in previous studies,
that 1,3-dimethyl-4,5-dipentadecylimidazolium (IMeH) can be
considered a phospholipid bioisostere. The long alkyl chains in
positions C4 and C5 provide the non-polar tails, while the
imidazolium head serves as the hydrophilic counterpart. The
inherent positively charged heterocycle is proposed to interact
electrostatically with phosphate groups of the neighboring
phospholipids, while the alkyl chains with a length of C15 interact
with the fatty acids of the phospholipids, cooperatively facilitating
membrane integration of the molecule.[12]
Based on this lipid analogue behavior, we propose a novel,
dicationic imidazolium salt (IMeNMe ) as the parent compound for
3
a new class of lipofection agents (see Scheme 1). We envisioned
that, in analogy to our previous work, instead of the common
glycerol linker of many cationic lipids, a dimethyl imidazolium
scaffold could serve directly as the hydrophilic head group. For
supporting membrane integration the long alkyl chains are
installed in the backbone. To enable lipofection, a quaternary
ammonium salt is installed as a second positive charge at the
head group. The attachment at the C2 position of the imidazolium
core leads to a highly directional substitution pattern, which
should, once incorporated into a membrane, lead to an exposure
of the positive charge on the membrane surface. As such,
favorable electrostatic interactions with nucleic acids and a
negatively charged cell surface should induce a high degree of
transfection.
As depicted in Scheme 2A, the synthetic route towards these
imidazolium salts allows for facile diversification and could give
access to easily modifiable tailor-made transfection reagents.
While the backbone can be adjusted in its lipophilic character, the
substitution pattern at the heteroatoms determines the integration
into the membrane. Most importantly the directional anchor at the
C2 position can be adjusted in length and exposition of the
positive charge (see Scheme 2B), providing the framework for a
series of easily accessible, novel and unique transfection
reagents, based on an imidazolium-based phospholipid analogue.
Scheme 2. A) Synthesis concept: Preparation of imidazolium-based
phospholipid analogues with different head groups. B) Selective modification of
functionality: Installing different substituents effects the properties of the
molecule. C) This work: Synthesis of IMeNMe
oxohexyl)carbamate, NH OAc, EtOH, HOAc, 110 °C, 18 h ii) TFA, CH
18 h, iii) MeI, K CO , THF, rt, 18 h. IMeH – i) paraformaldehyde, NH OAc, EtOH,
HOAc, 110 °C, 4 h ii) MeI, K CO , MeCN, 90 °C, 18 h.
3
–
i) tert-butyl (6-
4
2
Cl , rt,
2
2
3
4
2
3
For this study, both the established 1,3-dimethyl-4,5-
dipentadecyl-imidazolium iodide (IMeH)[12] and the novel 1,3-
dimethyl-4,5-dipentadecyl-2-(5-(trimethylammonio)pentyl)imida-
3
zolium iodide (IMeNMe ) salts were synthesized from the
corresponding symmetrical diketone. Condensation with
ammonia and a respective aldehyde, followed by exhaustive
methylation, allows for the formation of structural C2-diversified
phospholipid analogues in
a divergent fashion. As such,
condensation with an N-protected aminoaldehyde, followed by
deprotection and methylation, led to the desired compound
IMeNMe (Scheme 2; see SI for more details). Following this
3
divergent synthesis route, tailor-made derivatives are easily
accessible.
To prove our hypothesized molecular design and substantiate the
proposed activity of IMeNMe as a gene transfectant a series of
3
Results and Discussion
biophysical investigations were conducted. In the following
experiments, model biomembranes of different complexities were
used:
1-component:
DPPC;
3-component:
DPPC:DOPC:cholesterol (2:1:1) or DPPC:DOPE:cholesterol
(
2:1:1) and 5-component: DPPC:DPPG:DOPC:DOPG:cholester-
ol (45:5:20:5:25).[ The latter system served as a refined model of
8]
a biological plasma membrane, since it contained anionic lipids in
the order of 10 mol%. In all of these membranes, IMeNMe was
3
treated as a partial DPPC replacement.
2
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Chemistry - A European Journal
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RESEARCH ARTICLE
Figure 2. Characteristic AFM height images and cross-sectional area plots of
the fully hydrated, 5-component model biomembrane A) without, B) with
3
10 mol% IMeNMe . The scan size of the images is 5 µm x 5 µm.
Figure 1. Representative results of the Laurdan GP-data for A) 1-, B) 3- and C)
5-component model biomembranes as a function of temperature. Black: without,
red: with 10 mol% IMeNMe
3
.
Additionally, atomic force microscopy (AFM) was used to detect
possible IMeNMe -induced changes in lateral organization and
3
membrane morphology by comparing domain heights and their
distribution. To avoid membrane distortion, all measurements
were executed in a fluid AFM cell in tapping mode, gaining
information of the membrane structure in the fully hydrated state.
The AFM height images of the 5-component lipid mixture with and
Fluorescence spectroscopy was used to gain insights into the
impact of IMeNMe (10 mol%) on the lateral order and fluidity of
3
the membrane. For this, the temperature-dependent behavior
between 10 and 80 °C was analyzed using Laurdan[16] as a
fluorescent probe. This fluorophore shows environment-
dependent emission with a pronounced red-shift when changing
from unpolar to more polar environments. The generalized
polarization (GP) was recorded, with high values indicating a
highly unpolar environment of Laurdan, which is found in laterally
ordered gel phases. In contrast, the fluid phases show significant
disorder within the lipid chains, allowing water molecules to
diffuse into the upper chain region of the bilayer, causing a more
polar environment and decreased GP-values (see SI for more
details).
without 10 mol% IMeNMe
component lipid mixture, a height difference of 1.5 nm between l
and l domains is detected, which is in good agreement with
literature reports.[ The addition of 10 mol% IMeNMe
slightly smaller l domains, while a minor decrease of the domain
height difference to 1.1 nm is observed. These measurements
show that IMeNMe readily inserts into the membrane but does
3
are shown in Figure 2. For the neat, 5-
o
d
18]
3
leads to
d
3
not lead to drastic changes in the phase behavior or a
disintegration of the lateral organization of the lipid bilayer.
All GP-curves of the model membranes – both with and without
IMeNMe – show a sigmoidal-like progression with increasing
3
temperature. For the neat one-component bilayer, the main
transition temperature was found at 41 °C with a decrease of the
GP-values from 0.5 to values below zero during the gel-to-fluid
phase transition, which is in good agreement with previous
reports.[17] Upon addition of IMeNMe
the main transition
3
temperature is hardly affected, but slightly lower GP-values can
be detected in the lipid-ordered region – indicating a marginally
lower lipid packing density of the bilayer.
The same trend can be observed in the 3- (DPPC:DOPE:chole-
sterol) and 5-component lipid mixtures. Both lipid mixtures show
a broader transition behavior in comparison to the 1-component
model biomembrane, owing to the broad coexistence of liquid-
ordered (l
temperature leads to an increasing amount of l
is accompanied by an increase of fluidity and conformational
disorder. The addition of 10 mol% IMeNMe results in a minor
increase of the order parameter in the l phase (i.e. higher GP-
o
) and liquid-disordered (l
d
) domains. An increase in
d
domains, which
3
d
values). This effect is more pronounced for the 5-component
mixture than for the 3-component mixture. This observation might
be associated with the attractive interaction between the cationic
imidazolium and the anionic lipid headgroups.
Figure 3. Representative confocal fluorescence microscopy cross-sectional
images of GUVs with 10 mol% IMeNMe in A) the neutral 3-component model
3
biomembrane at different temperatures and B) the anionic 5-component lipid
vesicles with increasing temperature. GUVs labeled by N-rhodamine-DHPE.
The scale bar represents 20 µm.
3
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RESEARCH ARTICLE
Furthermore, confocal fluorescence microscopy measurements
were performed using giant unilamellar vesicles (GUVs). The
lateral domain structure and the morphology of lipid vesicles were
ethanolamine headgroup promotes negative membrane
curvature and therefore supports membrane fusion.[4,5,19]
As a target, a GUV of the 5-component lipid mixture labeled with
investigated upon addition of 10 mol% of IMeNMe
- (DPPC:DOPC:cholesterol) and the anionic 5-component model
biomembrane. N-rhodamine-DHPE[16] was used as a fluorophore,
which accumulates in the l domains of the GUVs.
For the 3-component model biomembrane, phase coexistence
can be observed up to 50 °C. At 75 °C, an all-fluid phase can be
detected (for images of the neat 3-component model membrane,
3
to the neutral
N-rhodamine-DHPE (red fluorescence; marking the l
d
phase) was
3
chosen. GUVs with IMeNMe were prepared via electroformation
3
and immobilized. The target vesicles were prepared employing
polyvinyl alcohol (PVA)-assisted swelling and added to the bulk
solution contacting the immobilized GUVs. Additionally, Atto-647
dye was inserted into the surrounding buffer, to evaluate the
quality of vesicle fusion and to identify potential pore formation or
leakage. The result was analyzed after an incubation time of 3
hours (see SI for more details).
d
3
see the SI). Interestingly, incorporation of IMeNMe induces an
aggregation of the lipid vesicles. This effect is even more
pronounced in the anionic 5-component model membrane,
presumably due to stronger electrostatic interactions with the
dicationic head group (Figure 3). For the 5-component model
biomembrane, phase separation occurs at temperatures below
In the absence of IMeNMe
vesicle types, nor mixing of the fluorophores could be observed
(Figure 4A). In the presence of IMeNMe , however, fusion of the
3
, neither close contact between both
3
2
0 °C, which is seen on the interacting surfaces of the adherent
vesicles, only. At around 65 °C an all-fluid phase is detected
images of the neat 5-component membrane can be found in the
vesicles could be detected, resulting in the coexistence of the
fluorophores in the same GUV (Figure 4B), with the fused vesicles
(
o d
still showing l and l phase separation at room temperature. Also,
SI). The pronounced adherence of the lipid vesicles – most likely
resulting from lipid sorting and interaction of the dicationic
imidazolium salt with the negatively charged lipids DOPG and
DPPG – suggests that IMeNMe could possibly induce membrane
3
fusion, thus serving as a first verification of the feasibility of our
initial compound design.
no Atto dye was detected inside the vesicles, indicating that the
fusion happens without membrane leakage. The same results
were obtained when the target vesicle was prepared via
electroformation, while the other vesicle was prepared via PVA-
assisted swelling and added to the bulk solution. Preparing both
vesicles by PVA-assisted swelling and adding them to the bulk
medium also led to vesicle fusion without leakage as well (see
Figure 4C).
Following the same preparation procedures, the fusogenic
properties of the monocationic IMeH were investigated (see SI for
details). Again, the vesicle interaction led to mixing of the two
membrane fluorophores, indicating that also this derivative is able
to induce fusion of lipid vesicles. Altogether, these data clearly
indicate fusogenic properties of both imidazolium-based lipids,
and thus support the design concept of imidazolium salts as
valuable transfection vehicles.
Figure 4. Confocal fluorescence microscopy cross-sectional images of the
IMeNMe vesicle fusion experiments. First column: GUVs labeled by NBD-
3
DHPE, Second column: GUVs labeled by N-rhodamine-DHPE; Third column:
Buffer marked with Atto-647; Fourth column: Combined image. A) GUVs without
IMeNMe
IMeNMe
IMeNMe
3
, green – solid supported; target, red – added in bulk. B) GUVs with
3
, green – solid supported; target, red – added in bulk. C) GUVs with
3
, green – added in bulk; target, red – added in bulk. The scale bar of
the images corresponds to 20 µm.
With these results in hand, we sought to investigate the fusogenic
properties of IMeNMe
microscopy-based assay. Therefore, a cargo lipid mixture of
DPPC:DOPE (1:1) containing 10 mol% IMeNMe and the
fluorophore NBD-DHPE[16] (green fluorescence; marking the l
3
in comparison to IMeH in a fluorescence
Figure 5. Liposome/IMeNMe
HeLa cells. A) No transfection reagent; B) Liposomes with IMeH as transfection
reagent; C) Liposomes with IMeNMe as transfection reagent. Confocal
3
-mediated transfection of a GFP plasmid into
3
o
3
microscopy images showing GFP fluorescence in the upper and phase contrast
in the lower panels; scale bar 10 µm.
phase) was used. Here, due to its application as so-called helper
lipid, DOPE was added. Helper lipids support induction of
transient and local non-lamellar phases in the lipoplex membrane
and therefore enhance internalization. For DOPE, the small
4
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RESEARCH ARTICLE
Given these detected fusogenic properties in the biophysical
3
To further study the transfection properties of IMeNMe ,
analyses, IMeNMe
3
and IMeH were next employed in cellular
was
Rhodamine-PE (RhoPE, 1 mol%) was introduced as fluorescently
labeled lipid into the liposome mixture and the cell interaction and
fusion events were monitored over time. The data show that the
liposomes appear to adhere to the cells prior to fusion and
distribution of the rhodamine label in the plasma membrane (see
SI for video). Furthermore, cells were fixed by paraformaldehyde
studies. First, the cytotoxicity of the novel IMeNMe
3
evaluated by a lactate dehydrogenase assay, which confirmed
that the molecule is tolerated by HeLa cells. Following,
DPPC:DOPE (1:1) liposomes with an optimized loading of
2
0 mol% of the respective imidazolium salt, which were prepared
via natural swelling, were incubated with cultured cells (HeLa) for
hours and the cells were then cultivated overnight (see SI for
3
(PFA) after incubation with the DPPC/DOPE/IMeNMe /RhoPE
4
liposomes and GFP protein expression overnight. As depicted in
Figure 6, an enrichment of RhoPE in the plasma membrane could
again be observed, indicating successful membrane fusion.
However, GFP plasmid expression could not be observed in every
more details). To assess their potential for gene transfer, a green
fluorescent protein (GFP) plasmid was added to the liposomes,
which enabled the identification of successfully transfected cells
through green fluorescence of the synthesized GFP.
rhodamine-positive cell, suggesting
a
somewhat limited
As depicted in Figure 5, liposomes without imidazolium salt are
unable to transfect the incorporated nucleic acid, i.e. no HeLa
cells showing GFP fluorescence are identified. Similarly, cells
treated with the IMeH-containing liposomes did not show
transfection efficiency, which was confirmed through quantitative
analysis (see SI for further details)
3
expression of the GFP plasmid. However, when IMeNMe -
containing liposomes were used, a successful transfection of the
GFP plasmid was achieved resulting in the green fluorescence of
the cells. Furthermore, the plasma membrane of the transfected
cells remained intact as the cells failed to take up propidium iodide
(
see SI for more details).
This activity difference of the imidazolium salts justifies the design
of IMeNMe and shows that the modification in the C2 position
3
with a second positive charge is crucial for successful transfection.
Most likely, the directional ammonium anchor protruding from the
phospholipid bilayer could increase the strength of electrostatic
interactions with nucleic acids and the negatively charged plasma
membrane, thereby enabling transfection.
Figure 7. Comparison of IMeNMe3 and Lipofectamin2000™ as means for
transfecting a GFP plasmid into HeLa cells. Cells were treated with IMeNMe3-
containing liposomes or Lipofectamin2000™, incubated overnight and GFP
expression was then monitored by confocal fluorescence microscopy; scale bar
10 µm.
This was further substantiated by comparing the transfection
effectiveness of IMeNMe liposomal mixtures with that of the
commercially available Lipofectamine 2000™
3
[
20]
as a well-
established transfection agent, revealing lower transfection
efficiency, but similar expression levels (as judged by
fluorescence intensity) of the GFP protein (see Figure 7).
Beyond the previously discussed HeLa cells, we next evaluated
3
the transfection effectiveness of IMeNMe in fibroblasts. As
depicted in Figure 8, transfection of the GFP plasmid could be
carried out successfully, albeit with lower efficiency than using
Lipofectamin 2000.[20]
3
Figure 6. Transfection with IMeNMe liposomes containing Rhodamin-PE lipid
to evaluate lipid distribution after transfection. Note that an enrichment of
Rhodamin-PE in the plasma membrane can be observed. Blue – Hoechst,
nuclear fluorescence. Red
– Rhodamin-PE, lipid fluorophore. Green –
expressed GFP; scale bar 10 µm.
5
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Chemistry - A European Journal
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RESEARCH ARTICLE
easily prepared and offer facile access to structural diversity
–
addressing current challenges such as low efficiency across
many cell types, and difficulties in cationic lipid preparation.
Acknowledgements
We thank Johannes Nass and Nikita Raj for providing the
plasmids, as well as Tristan Wegner, Felix Strieth-Kalthoff and
Toryn Dalton for helpful discussions. Financial support by the
Deutsche Forschungsgemeinschaft (GRK 2515/1; SFB 858,
EXC 1003 Cells in Motion Cluster of Excellence) is gratefully
acknowledged. RW acknowledges funding from the Deutsche
Forschungsgemeinschaft (DFG, German Research Foundation)
Figure 8: Representative confocal fluorescence microscopy images of
IMeNMe3-liposomal transfection (DPPC/DOPE/IMeNMe3, A: 40/40/20 mol%,
D:Lipofectamine™ 2000) of fibroblasts. Confocal microscopy images showing
merge between GFP fluorescence and phase contrast; scale bar 100 µm.
under Germany's Excellence Strategy
Projektnummer 390677874.
–
EXC-2033
–
3
Additionally, we investigated IMeNMe mediated transfection
efficiency for another plasmid, which encoded the endosome
targeting sequence Phe-Tyr-Val-Glu fused to GFP (2xFYVE-
GFP). Figure SI 4 shows that HeLa cells were successfully
transfected also with this plasmid, further expanding the scope of
the reported transfection protocol.
Keywords: transfection • imidazolium • biophysics • liposomes •
lipids
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[
[
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3
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8
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Abbreviations
for
phospholipids:
1,2-dioleoyl-sn-glycero-3-
phosphocholine (DOPC), 1,2-dipalmitoyl-sn-glycero-3-phosphocholine
(
DPPC), 1,2-dioleoyl-sn-glycero-3-phospho-(1’-rac-glycerol) sodium salt
DOPG), 1,2-dipalmitoyl-sn-glycero-3-phospho-(1’-rac-glycerol) sodium
(
salt (DPPG), 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE).
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RESEARCH ARTICLE
Entry for the Table of Contents
Can’t get transfection? A transfection reagent based on a dicationic imidazolium salt was developed. Detailed analyses of membrane
incorporation, adhesion of vesicles and fusogenic properties of the salt are described. Cell experiments show the successful in vivo
application of this new class of transfection reagents.
8
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